supplementary information doi: 10.1038/nmat4259 ... · , renren deng. 2, xiaogang liu. 2,3 *, &...

SUPPLEMENTARY INFORMATIONDOI: 10.1038/NMAT4259

NATURE MATERIALS | www.nature.com/naturematerials 1

1

Supplementary Information

Stabilizing excited triplet state for ultralong organic phosphorescence

Zhongfu An1,4†, Chao Zheng1†, Ye Tao1, Runfeng Chen1, 4*, Huifang Shi4, Ting Chen1, Zhixiang Wang1,

Huanhuan Li1, Renren Deng2, Xiaogang Liu2,3*, & Wei Huang1,4*

1Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials,

Jiangsu National Synergistic Innovation Center for Advanced Materials, Nanjing University of Posts and

Telecommunications, Nanjing, 210023, P.R. China. 2Department of Chemistry, National University of

Singapore, 117543, Singapore. 3Institute of Materials Research and Engineering, Agency for Science,

Technology and Research, Singapore 117602, Singapore. 4Key Laboratory of Flexible Electronics & Institute

of Advanced Materials, Jiangsu National Synergistic Innovation Center for Advanced Materials, Nanjing

Tech University, Nanjing 211816, P.R. China.

Contents

I. Additional experimental details …………………………………………………………....2

II. Room-temperature photoluminescence investigations …………..………………………. 5

III. Temperature-dependent organic phosphorescence ………………………………………..11

IV. Exitation strength and duration consideration ……………………………………………13

V. Time-dependent density functional theory (TD-DFT) calculations..……………..………17

VI. Experimental validation of triplet excited states ……………………………………..…...32

VII. Understanding molecular aggregation .………………………….………………………...34

VIII. Comparative photoluminescent studies of DECzT, DEOPh, DPhCzT, CzDClT

and DCzPhP ………………………………………………………………………………...37

IX. Data encryption application ………………………………………………………………. 41

X. Supplementary videos ….………………………………………………………………….. 41

XI. References …………………………………………………………………………………. 42

Stabilizing triplet excited states for ultralong organic phosphorescence

© 2015 Macmillan Publishers Limited. All rights reserved

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2 NATURE MATERIALS | www.nature.com/naturematerials

SUPPLEMENTARY INFORMATION DOI: 10.1038/NMAT4259

2

I. Additional experimental details

General. Unless otherwise noted, all reactions were carried out under a nitrogen atmosphere using

standard Schlenk techniques. Tetrahydrofuran (THF) was dried and distilled over sodium/benzophenone.

All other chemicals and deuterated solvents were obtained from commercial sources and used as received

unless otherwise noted.

Physical measurements. 1H NMR and 13C NMR spectra were recorded on a Bruker Ultra Shield Plus

400 MHz spectrometer and referenced to tetramethylsilane (TMS) as the internal standard. Mass spectra

were obtained on a matrix-assisted laser desorption/ionization time of flight mass spectrometry

(MALDI-TOF-MS) or a Shimadzu GCMS-QP2010 instrument. Elemental analysis was performed on an

Elementar Vario MICRO elemental analyzer. Ultraviolet-visible (UV-Vis) and steady-state fluorescence

spectra were obtained using a SHIMADZU UV-3600 UV-VIS-NIR spectrophotometer and a RF-5301PC

spectrofluorophotometer, respectively. The time-resolved excitation spectra, kinetic measurements,

lifetime, and time-resolved emission spectra were measured using an Edinburgh FLSP920 fluorescence

spectrophotometer equipped with a xenon arc lamp (Xe900), a nanosecond hydrogen flash-lamp (nF920)

and a microsecond flash-lamp (uF900), respectively. For fluorescence decay measurements, sub-

nanosecond optical pulses over the VUV-to-NIR spectral range were provided using a hydrogen flash

lamp. The microsecond flash lamp produces short, typically a few μs, and high irradiance optical pulses

for phosphorescence decay measurements in the range from microseconds to seconds. The lifetimes (τ) of

the luminescence were obtained by fitting the decay curve with a multi-exponential decay function of

( ) i

t

ii

I t Ae

where Ai and τi represent the amplitudes and lifetimes, respectively, of the individual components for

multi-exponential decay profiles. The PL spectra of the sample were measured using a Horiba-Spex

Fluorolog-3 spectrophotometer at various temperatures from 300 to 12 K. The sample was cooled down

by a Cryo-Mini cryogenic refrigerator with a closed cycle helium optical cryostat. The PL spectra at

temperatures from 303 to 423 K were measured by Fluorlog-3 spectrofluorometer equipped with a 450-

W xenon lamp (Horiba JobinYvon) in combination with a heating apparatus (TAP-02). The XRD

patterns were collected on a D/max-2500/PC diffractometer using Cu-Kα radiation (λ = 1.5405 Å). The

morphology of the sample dispersed in THF/H2O was characterized using JEOL JSM-6701F Field

Emission Scanning Electron Microscopy (FESEM) and JEOL JEM-1400 transmission electron

microscope (TEM) operated at 100 KV. The photos and supporting videos were recorded by a Nikon D90

camera. The ultralong phosphorescence intensity decay curves were achieved using a PR305 photometer

after the sample was irradiated by either 254 or 365 nm UV light or simulated sunlight with 1000 ± 5%

lx for 10 min. X-ray crystallography was carried on a Bruker SMART APEX-II CCD diffractometer

with graphite monochromated Mo-Kα radiation.





3

Preparation of ultralong organic phosphorescent molecules. We designed and synthesized a series of

organic molecules (DPhClT, DEOPh, DECzT, CzDCIT, and DCzPhP) that comprise O, N, and P atoms

capable of promoting spin-forbidden singlet-triplet intersystem crossing. These molecules were fully

characterized by 1H NMR, 13C NMR, GC-MS, MALDI-TOF, element analysis, and single crystal X-ray

diffraction analysis.

4,6-Diphenyl-2-chloro-1,3,5-triazine (DPhClT). A solution of bromobenzene (8.7 g; 55.4 mmol) in dry

THF (50 mL) was slowly added to a stirred mixture of magnesium turnings (1.38 g; 57.5 mmol) and a

catalytic amount of iodine (0.1 g) in THF (20 mL). The resulting Grignard reagent was then added

dropwise at 35 oC to a 250 mL round-bottom flask charged with 2,4,6-trichloro-1,3,5-triazine (3.0 g; 16.2

mmol) in THF (20 mL). After stirring for 12 h, the mixture was poured into water to quench the

reaction. The crude product was extracted with CH2Cl2 for three times. The organic layers were collected

and dried over NaSO4. The solvent was removed by rotary evaporation, and the residue was purified by

flash column chromatography to give DPhClT (2.18 g; 50%) as a white solid. 1H NMR (CDCl3): δ 8.59 (d,

4 H), 7.61 (t, 2 H), 7.52 (t, 4 H). 13C NMR (CDCl3): δ 173.36, 172.17, 134.35, 133.56, 129.40, 128.82. GC-

MS: (CH2Cl2, m/z): 267. Anal. Calcd for C15H10N3Cl: C, 67.30; H, 3.77; N, 15.70. Found: C, 67.26, H, 3.85,

N, 15.52.

4,6-Diphenyl-2-carbazolyl-1,3,5-triazine (DPhCzT). To a 20 mL round-bottom flask charged with 9H-

carbazole (0.15 g; 0.90 mmol) was injected dry THF (5 mL) with a syringe under a nitrogen atmosphere.

The solution was cooled in an icy bath and stirred for 10 min, at which time a 1.6 M hexane solution of

n-butyllithium (0.56 mL; 0.90 mmol) was added slowly. The resulting mixture was stirred for 30 min at

room temperature to yield yellow slurry of N-lithium carbazole. Then a mixture of DPhClT (0.2 g; 0.75

mmol) and Pd(PPh3)4 (93 mg; 0.08 mmol) in THF (5 mL) was slowly added to the flask, resulting in the

precipitation of solid products. The mixture was heated at 80 oC overnight to improve the yield. The

precipitation was collected and washed with water and acetone for several times. Recrystallization of

the solid in chlorobenzene for several times afforded DPhCzT (0.2 g; 65%) as a white powder. 1H NMR

(CDCl3): δ 9.17 (d, 2H), 8.78 (t, 4H), 8.10 (d, 2H), 7.66~7.60 (m, 8H), 7.45 (t, 2H). 13C NMR (CDCl3): δ

172.51, 165.26, 139.17, 136.31, 132.73, 129.16, 128.84, 127.03, 126.69, 123.31, 119.69,117.74. MALDI-

TOF (m/z): calcd for C27H18N4, 398.46. Found: 399.391. Anal. Calcd for C27H18N4: C, 81.39; H, 4.55; N,

14.06. Found: C, 81.43, H, 4.78, N, 13.77.

2-Carbazolyl-4,6-dichloro-1,3,5-triazine (CzDClT). Following the same synthetic procedure for

DPhCzT, the reaction of 9H-carbazole (1.0 g; 6.0 mmol) and 2,4,6-trichloro-1,3,5-triazine (1.22 g; 6.6

mmol) in 1.6 M n-butyllithium/hexane solution (4.1 mL, 6.6 mmol) at 0 oC for 4 h yielded CzDClT (1.4 g;

74%) as a white powder. 1H NMR (CDCl3): δ 8.83 (d, 2H), 7.98 (d, 2H), 7.52 (d, 2H), 7.44 (d, 2H). 13C

NMR (CDCl3): δ 170.92, 163.42, 138.12, 127.69, 127.42, 125.06, 119.75, 118.85. GC-MS (CH2Cl2, m/z):

314. Anal. calcd for C15H8N4Cl2: C, 57.17; H, 2.56; N, 17.78. Found: C, 57.32, H, 2.61, N, 17.64.





4

4,6-Diethoxy-2-carbazolyl-1,3,5-triazine (DECzT). Sodium (0.031 g; 1.3 mmol) was carefully dissolved

in 2 mL ethyl alcohol to form sodium ethylate, which was slowly added to a stirred solution of CzDClT

(0.2 g; 0.63 mmol) in 5 mL ethanol. The solution was then stirred at room temperature for 5 min, at

which time water was added to quench the reaction. The crude product was extracted with CH2Cl2 for

three times. The organic layers were collected and dried over sodium sulfate. The solvent was removed

by rotary evaporation and the residue was purified by flash column chromatography to give DECzT

(0.19 g; 91%) as a white solid. 1H NMR (CDCl3): δ 8.95 (d, 2H), 8.00 (d, 2H), 7.49 (t, 2H), 7.38 (t, 2H),

4.60 (q, 4H), 1.53 (t, 6H). 13C NMR (CDCl3): δ 172.09, 166.46, 139.00, 127.00, 126.59, 123.36, 119.47,

118.15, 64.42, 14.42. MALDI-TOF (m/z): calcd for C19H18N4O2, 334.37. Found: 334.38.

1,4-Diethoxybenzene (DEOPh): To a 50 mL round-bottomed flask charged with sodium (0.46 g; 20

mmol) in 15 mL ethanol was added hydroquinone (1.0 g; 9.08 mmol) dissolved in 7.5 mL ethanol. After

stirring at room temperature for 1 h, 1-bromoethane (1.71 mL; 23.06 mmol) was added dropwise into the

reaction solution. The resulting mixture was then heated at 60 oC for 3 h, at which time the solution was

poured into a beaker containing 20 mL water and further extracted with CH2Cl2. The organic layers

were collected and dried over sodium sulfate. The solvent was removed by rotary evaporation, and the

residue was purified by flash column chromatography to give DEOPh as a white solid (1.36 g; 90%). 1H

NMR (CDCl3): δ 6.82 (s, 4H), 3.97 (q, 4H), 1.38 (t, 6H). 13C NMR (CDCl3): δ 153.03, 115.40, 64.00, 14.97.

Di(9H-carbazolyl)-phenylphosphine (DCzPhP). Carbazole (1.00 g; 5.99 mmol) was dissolved in 20 mL

of anhydrous THF and cooled to -78 ºC in a dry ice/acetone bath under a nitrogen atmosphere. A 1.6 M

hexane solution of n-butyl lithium (4.5 mL; 7.2 mmol) was then added dropwise to the THF solution.

After reaction for 1 h at -78 ºC, dichlorophenylphosphine (0.41 mL; 2.99 mmol) was added to the

solution mixture. Subsequently, the mixture was stirred at -78 ºC for 1 h and then kept at room

temperature overnight. The reaction was quenched with water (10 mL), and the solution was extracted

with CH2Cl2 (3 × 30 mL). The organic layers were collected and dried with anhydrous Na2SO4. The

solvent was removed by rotary evaporation, and the residue was purified by column chromatography to

afford DCzPhP (0.79 g; 60%) as a white powder. 1H NMR (d-DMSO): δ 8.12-8.09 (m, 4H), 7.63-7.59 (m,

1H), 7.55-7.44 (m, 8H), 7.28-7.22 (m, 8H). 13C NMR (d-DMSO): δ 142.86, 142.81, 131.69, 131.53, 131.46,

131.24, 130.27, 130.21, 126.81, 126.08, 122.04, 121.11, 113.55, 113.42.





5

Scheme S1. Synthetic approaches to accessing organic molecules of DPhCzT, DECzT, CzDClT,

DEOPh and DCzPhP exhibiting ultralong phosphorescence. (i) 2.2 equiv. Mg, bromobenzene, 35 oC, 12

h; (ii) 1.1 equiv. n-BuLi, carbazole, Pd(PPh3)4, 85 oC, 12 h; (iii) 1.1 equiv. n-BuLi, carbazole, 0 oC, 2 h; (iv) 2.1 equiv.

Na, ethanol, room temperature, 5 min; (v) 2.2 equiv. Na, ethanol, 1-bromoethane, 60 oC, 3 h; (vi) 2.2 equiv. n-BuLi,

carbazole, -78 oC to room temperature, 12 h.

II. Room-temperature photoluminescence investigations

In a chloroform solution of DPhCzT (1.0×10-5 M), a broad fluorescence emission (τ = 12.4 ns) at 480

nm was observed upon UV excitation at 325 nm (Figures S1, a and b), which can be ascribed to the

charge transfer commonly occurring in the excited states of conventional donor-acceptor organic

emitters.1-3 In contrast, its photoluminescence spectrum in the solid state is rather complex. The

emission peaks at 416, 440, 465, and 493 nm contain the components of not only the fluorescence (τ < 20

ns) but also the delayed fluorescence (τ ~ 500 ms). By comparison, the emission peaks at 530 and 575 nm

have only ultralong (τ > 1 s) luminescent component (Figure S1c and Table S1). The ultralong

luminescence at 530 and 575 nm shown in Figure S1d is very different from the excimer emission

typically having a broad featureless band.4 The featured long-lived emission is inert to atmospheres of

oxygen, argon, and air, as verified by not only stead-state and time-resolved photoluminescence

spectroscopies but also the video taken on and off the UV excitation (Figure S1, e-g and Video SV1).





6

Figure S1. Photoluminescence characterizations of DPhCzT at 300 K. a, Normalized UV absorption

(black, Abs) and steady-state photoluminescence (red, Em) spectra of DPhCzT in chloroform (1.0×10-5 M)

excited at 322 nm under ambient conditions. b, Lifetime decay profile of the emission band at 480 nm excited at

322 nm in chloroform solution. c, Lifetime decay profiles of fluorescent emission bands (416, 440, 465, and 493

nm) of the DPhCzT powder excited at 365 nm. d, Normalized ultralong luminescent spectra of the DPhCzT

powder at delay times of 172, 540, 1071, 5035, and 8008 ms, respectively. e, Normalized steady-state

photoluminescence spectra of the DPhCzT powder excited at 365 nm in air, argon, and oxygen, respectively. f

and g, Lifetime decay profiles of the emission bands at 530 and 575 nm of the DPhCzT powder excited at 365

nm in argon and oxygen, respectively.





7

Table S1. Photoluminescence lifetimes (τ) of DPhCzT, DEOPh, DECzT, CzDClT, and DCzPhP

powdersa

Compound Wavelength

(nm)

Fluorescence

Ultralong luminescence

τ1 (ns) A1 (%) τ2 (ns) A2 (%) τ1 (ms) A1 (%) τ2 (ms) A2 (%)

DPhCzT 416 2.15 96.23 16.68 3.77 374.02 100 - -

440 2.12 84.10 16.73 15.90 570.13 100 - -

465 2.20 61.54 18.63 38.46 676.68 100 - - 493 2.19 31.57 18.93 68.43 746.95 100 - -

530 - - - - 1066.00 100 - -

573 - - - - 1052.18 100 - -

DEOPh 515 325.99 31.85 709.79 68.15

547 249.57 24.69 691.69 75.31

DECzT 529 437.60 2.61 1281.59 97.39 574 669.52 13.78 1347.35 86.22

CzDClT 543 - - - - 107.38 34.32 470.82 65.68

591 - - - - 102.43 34.43 491.21 65.55

DCzPhP 587 208.63 100 - -

644 207.11 100 - -

aDetermined from the fitting function of I(t) = A1e-t/τ1 + A2e-t/τ2 according to the fluorescence and ultralong

luminescence decay curves. Note that the compound of DEOPh is excited at 254 nm whereas other compounds

are excited at 365 nm.

The emission lifetimes in most of the reported organic phosphorescent materials are in the range of μs

to ms at room temperature, which are mainly induced by inorganic metals, such as Ir3+ Ru3+, Os3+and

Pt2+.5 These resource-limited metals are not only costly but also highly toxic. Alternatively, special

organic moieties (e.g., aromatic aldehyde, heavy halogen, and deuterated carbon) can be incorporated

into the organic frameworks to increase emission lifetimes at room temperature.6-8 However, the

stringent conditions and/or short emission lifetime window in above-mentioned systems have posed

significant constraints in developing time-resolved luminescent applications.

To further demonstate ultralong photoluminescence of DPhCzT powder, we carried out control

experiments and directly compared our dyes to traditional organic and metal-complex dyes, including

classic n-π* material (benzophenone), organic light emitting diode (OLED) materials (NPD and CBP),

and typical metal-complexes (Ir(ppy)3 and FIrpic). NPD, CBP, Ir(ppy)3 and FIrpic refer to N,N’-

diphenyl-N,N’-bis(1-naphthyl)(1,1’-biphenyl)-4,4’-diamine, 4,4’-bis(9-carbazolyl)-2,2’-biphenyl, tris[2-

phenylpyridinato-C2,N]iridium(III), and bis[4,6-difluorophenyl)pyridinato-N,C2’]iridium(III) picolinate, as

illustrated in Figure S2. It is obvious that except for DPhCzT, none of these traditional dyes exhibited

long emission after the turn off of the UV excitation in a dark room (Figure S3 and Video SV2).





8

Table S2. Reported room-temperature emission lifetimes and quantum efficiencies of

common organic dyes, metal-complexes and rare-earth dyes, and the ultralong

phosphorescent dyes under current investigation Compound Lifetime (ms) Quantum Efficiency (%) Reference

Fluo Phos Purely organic dye DPA 1.25 ×10-5 86a - 9

BODIPY 3.86 ×10-6 90b - 10 CBP 1.25 ×10-6 61a - 11 NPD 3.5 ×10-6 29a - 12 Benzophenone 0.31 - 15.9a 13 Metal-complex PtOEP 9.1×10-2 - 50c 14

Ir(dfppy)2(tpip) 7.7×10-4 - 3.81b 15 Ir(ppy)3 ~7.65×10-5 - 26a 16,17 FIrpic 4.36×10-4 - 16a 18,19 Rare-earth dye Eu(tta)3(L) 8.0×10-4 - 80c 20

Tb(bpatcn) 1.49 - 43a 21 Ultralong Phosphorescent dye

DPhCzT 1.06×103 4.35a 1.25a Our work DEOPh 7.1×102 9.1a 0.3a Our work DECzT 1.35×103 20.5a 0.6a Our work CzDClT 4.9×102 13.1a 2.1a Our work DCzPhP 2.9×102 4.89a 0.08a Our work

a in solid state; b in solution; c in composites

Figure S2. Molecular structures of the organic dyes, metal-complexes and rare-earth dyes shown

in Table S2.





9

Figure S3. Snapshots of DPhCzT, common organic molecules and metal-complexes taken at

different time intervals before (first row) and after (succeeding rows) turn-off of the excitation

(365 nm) under ambient conditions.

The extraordinary ultralong photoluminescence of DPhCzT is also very different from its

phosphorescence spectrum measured in toluene solution at 77 K (Figure S4, a). At the low temperature,

the phosphorescence can last for more than 10 s. However, the line shape of the phosphorescence

spectrum peaked at 419, 448, 472, 482 nm, significantly differs from that of the ultralong

photoluminescence peaked at 530 and 575 nm (Figure S1, d). In contrast, the phosphorescence spectra

measured in powder form at 77 K after 100 ms delay are very similar to the ultralong phosphorescent

spectra measured at room temperature (Figure S4, b), providing direct envidence on the existence of a

stabilized triplet excited state in solid state which is absent in solution.

Upon UV excitation (1000 ± 5% lx) at 254 and 365 nm, the ultralong photoluminescence of

DPhCzT can last for 7 and 9 s above a recognizable intensity level (≥ 0.32 mcd/m2),22 respectively. The

fading process of the long organic photoluminescence can be recorded in videos (Video SV3) using a

household camera or conventional optical microscope (Figure S5) after switching off of the UV

excitation. Impressively, when irradiated by simulated sunlight under identical conditions, the lasting

time of the ultralong photoluminescence can be elongated up to 56 s at room temperature. Such a long

lifetime of the photoluminescence suggests long-lived excited states responsible for the observed

emission. Notably, the long-lived excited states offered by these molecules after sunlight excitation are

very attractive for developing high-performance solar cells due to the promoted dissociation probability

of the long-lived excitons that can migrate over a considerably long distance as found in perovskite-type

solar cells. 23-25





10

Figure S4. Photoluminescence characterizations of DPhCzT at 77 K. a, Time-resolved

phosphorescence spectra of DPhCzT in toluene excited by 325 nm UV-light. The color bar represents intensity

count. b, Normalized photoluminescent spectra of the DPhCzT powder excited by 365 nm UV-light at delay

times of 5, 15, 100, 500, and 1000 ms, respectively.

Figure S5. Microscopic photographs of DPhCzT crystals taken upon excitation at 350 ± 50 nm (a) and after

turn-off of the excitation at different time (b-d: 250, 500, and 800 ms, respectively). Scale bar: 150 μm. Note

that the emission was collected through a band-pass filter with a bandwidth of 535 ± 50 nm.





11

III. Temperature-dependent organic phosphorescence

We first investigated the effects of temperature on the ultralong organic luminescence, either by

decreasing the temperature from room temperature to 10 K or by cycling temperature between 303 and

423 K. As to the absolute luminescent quantum efficiency, the ultralong phosphorescence efficiency

increases only slightly when the temperature decreases from 300 to 10 K, indicating the insensitivity of

the ultralong phosphorescence toward temperature. The increased luminescent efficiency at low

temperature is mainly contributed by the significantly increased fluorescence efficiency (Figure S6). At

extremely low temperature of 10 K, the utralong luminescence peaked at 530 and 575 nm did not

disappear but showed increased lifetime up to 2.3 s with enhanced strength (Figure S7, a), further

suggesting the band-structure transition of the ultralong organic luminescence. However, with increase

in temperature, this featured ultralong luminescence gradually decreased and disappeared at 383 K

(Figure S7, b). Interestingly, it can recover at 363 K as temperature drops (Figure S7, c), demonstrating

the reversible behavior of the ultralong organic luminescence toward temperature. This characteristic

may find potential application as lifetime-dependent reversible thermal recording media. The

disappearance and recovery of the ultralong organic phosphorescence were attributed to the enhanced

non-irradiative deactivation processes at elevated temperature as the change of molecular packing

structure at various temperatures is negligible as revealed by X-ray diffraction patterns (Figure S8).





12

Figure S6. The fluorescence and phosphorescence quantum efficiencies of DPhCzT powder

measured at different temperatures.

Figure S7: Temperature-dependent photoluminescence of DPhCzT powder. a, Lifetime decay profiles

of the organic luminescence peaked at 530 and 575 nm at 10 K. b and c, The steady-state photoluminescence

spectra of DPhCzT recorded with increasing temperatures from 303 to 423 K and decreasing temperatures

from 423 to 303 K, respectively.





13

Figure S8: X-ray diffraction patterns of DPhCzT powder obtained at temperatures from 298 to

423 K. As temperature increases, a limited change in molecular packing structure was detected. The 2θ values

around 20.6o and 10.0o shifted 0.22o and 0.12o, respectively, corresponding to the interplanar distance increment

of 0.045 and 0.105 Å, according to Bragg's law (nλ = 2d × sinθ, where n is an integer, λ is the wavelength of

incident wave (λ = 1.5405 Å), d is the spacing between the planes in the atomic lattice, and θ is the angle

between the incident ray and the scattering planes).

IV. Exitation strength and duration consideration

The influence of the excitation strength on ultralong luminesccence of DPhCzT powder was

investigated by monitoring its emission intensity at 530 nm with different Iris of the excitation light at

365 nm. Iris is a parameter used to adjust the excitation light intensity in Edinburgh FLSP920

fluorescence spectrophotometer. When increasing Iris from 20% to 100%, the excitation intensity

increases linearly. As shown in Figure S9, during the measurement, the excitation at 365 nm with varied

Iris was turned on at 5 s, maintained for 10 s, and then turned off. The resultant emission intensity

remains stable during the excitation at 365 nm for 10 s, and then decays in exponential manner after

turn-off of the excitation.





14

Figure S9. The influence of excitation strength on ultralong luminescence of DPhCzT powder. a,

Intensity profile of the 530 nm emission as a function of time and different Iris (20, 40, 60, 80 and 100 %) when

excited at 365 nm under ambient conditions. The sample was irradiated for 10 s, during which time the steady-

state photoluminescence strength at 530 nm was measured. The luminescence was collected when the light

source was switched off. b, The strength of the steady-state photoluminescence and ultralong luminescence

measured at 365 nm with varied excitation intensities.

The influences of the excitation duration on the ultralong luminescence of DPhCzT powder were

investigated by monitoring its emission band at 530 nm with different irradiating time of the ultraviolet

light (λex = 365 nm). The steady-state emission intensity is almost constant when the excitation duration

extends from 0.02 to 10 s (Figure S10). For ultralong luminescence, even if the excitation duration is

0.02 s, it can last for 5 s (Figure S10, a). The intensity of ultralong luminescence is only slightly affected

by different irradiating time (Figure S10, b). Intriguingly, the ultralong luminescence can be effectively

excited by low intensity and short durations of excitation under ambient conditions. The high stability

of the ultralong organic phosphorescence was also confirmed by repeated time-dependent intensity

scans for 100 times without photo-bleaching (Figure S10, c).





15

Figure S10. The influence of excitation duration on ultralong luminescence of DPhCzT powder. a,

Intensity profiles of the 530 nm emission of the DPhCzT powder as a function of time upon excitation with

different irradiating time (λex = 365 nm) under ambient conditions. b, Corresponding intensities of the steady-

state and ultralong luminescence of the DPhCzT powder at 530 nm obtained with the excitation turned on and

off, respectively. The sample was irradiated for 0.02, 0.04, 0.06, 0.08, 0.1, 0.2, 0.4, 0.6, 0.8, 1, 2, 4, 6, 8, and 10 s,

respectively c, Time-dependent intensity scans of the emission at 530 nm obtained with the excitation switched

on and off for 2 and 4 s, respectively, for 100 times.

To further probe the influence of aggregated states on the organic phosphorescence, DPhCzT in

poly(methyl methacrylate) (PMMA) thin films was prepared to mimic the rigid environment in solid

states and to avoid the intermolecular interaction of DPhCzT. PMMA films containing DPhCzT at

different concentrations (0.5, 1, 5 and 10 wt.%) were obtained by spin-coating of the mixed precursors

dissolved in chloroform. As shown in Figure S11, only a broad emission band centered at 455 nm with

long lifetime (4 μs < τ < 110 μs, Table S3) was observed, which is quite different from that observed for

the sample without the PMMA. This control experiment suggests the important role of molecular

aggregation of DPhCzT in achieving ultralong organic phosphorescence.





16

Figure S11. Photoluminescence characteristics of DPhCzT/PMMA composite films under ambient

conditions. a, Lifetime decay profiles of PMMA film doped with DPhCzT at different concentrations (0.5, 1, 5

and 10 wt.%). The excitation and emission wavelengths were fixed at 365 and 455 nm, respectively. b, The steady-

state photoluminescent spectra of the DPhCzT/PMMA composite under 365 nm excitation.

Table S3. Photoluminescence lifetimes (τ) of DPhCzT/PMMA composite films at 455 nm under

ambient conditionsa

Concentration

wt %

Photoluminescence

τ1 (μs) A1 (%) τ2 (μs) A2 (%) τ3 (μs) A3 (%)

10% - - 11.98 55.59 68.08 44.41

5% 4.40 13.23 18.21 45.77 81.83 41.00

1% 5.87 13.54 24.29 40.28 100.37 46.18

0.5% 8.22 16.07 28.38 36.32 106.42 46.81

aDetermined from the fitting function of I(t) = A1e-t/τ1+A2e-t/

τ2+ A3e-t/τ3 from the photoluminescent decay curves.

Note that the sample was excited at 365 nm.

The DPhCzT aggregates formed in THF with a water content of 20 % were investigated by scanning

electronic microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). As

shown in Figure S12, a and b, the samples are one-dimensional nanowires with widths of 100 to 200 nm

and lengths of several micrometers. Good crystallinity of the nanocrystals was confirmed by XRD

studies with diffraction patterns consistent with that of DPhCzT powder (Figure S12, c).





17

Figure S12. SEM, TEM, and XRD characterizations of DPhCzT molecules dispersed in THF/H2O

(20/80; v/v) at 300 K (a-c, respectively).

V. Time-dependent density functional theory (TD-DFT) calculations

TD-DFT calculations were performed on Gaussian 09 program (Revision A. 02).26 The ground (S0)

and lowest triplet (T1) state geometries were fully optimized with the Becke’s three-parameter exchange

functional along with the Lee Yang Parr’s correlation functional (B3LYP) using 6-31G (d) basis sets.

These optimized stationary points were further characterized by harmonic vibration frequency analysis

to ensure that real local minima had been found. The excitation energies in the n-th singlet (Sn) and n-th

triplet (Tn) states were obtained using the TD-DFT method based on an optimized molecular structure

at ground state (S0). The π-π stacked H-aggregated states of the dimers were calculated with M062X/6-

31G(d) to take into consideration the weak long-range intermolecular interactions.27 The triplet energy

stabilization energy was calculated by the difference between the total molecular energy of the dimer

and a sum of the total molecular energy of the two monomers on S0 and T1, respectively. Electron

density differences (EDD) upon the S0→S1 and S0→Tn transitions based on optimized S0 geometries were

carried out using Multiwfn by subtracting the electron density of optimized grounded-state (S0) from

that of interested singlet or triplet excited states.28,29 The Yellow and blue colors correspond to the

decrease and increase of the electron density, respectively. Spin density distributions of T1 states were

generated and visualized using Gaussview 5.0 with an isovalue of 0.004.

From the single crystal structure of DPhCzT, there are three different forms of dimer structures

(Figure S13), including face-to-face aggregation (H-aggregation), L-shaped aggregation, and cross-

shaped aggregation. When Tn contains the same transition orbital compositions as S1 and its energy level

lies with ES1 ± 0.3 eV, the singlet-to-triplet transition from S1 to Tn is considered to be the possible

channels for the intersystem crossing. Under the same criteria, H-aggregation has more transition

channels (S1→T1, S1→T2, S1→T3, S1→T7, S1→T9, and S1→T10) for intersystem crossing in comparison

with the monomer and the other two forms of aggregations (Figures S13 and S14, Tables S4-7),

according to the TD- DFT calculations on DPhCzT dimer with different forms of aggregated structures.





18

Figure S13. The lowest singlet (S1) and triplet (Tn) states of a DPhCzT monomer and its dimer

obtained by TD-DFT calculations based on the single-crystal structure data of DPhCzT. a, Monomer.

b, H-aggregation. c, L-shaped aggregation. d, Cross-shaped aggregation. Insets are the molecular geometries. The

triplet states marked in green contain the same transition configuration compositions as in S1. The triplet states

in gray are those levels with energy higher than ES1 + 0.3 eV or lower than ES1 - 0.3 eV.





19

Figure S14. The TD-DFT calculated isosurfaces of the triplet states that contain the same

transition configuration of S1 and Tn in a DPhCzT monomer and its dimers. a, Monomer, b, H-

aggregated dimer, c, L-shaped aggregated dimer, d, Cross-shaped aggregated dimer.





20

Table S4. The singlet and triplet excited state transition configurations of DPhCzT monomer

revealed by TD-DFT calculations. The matched excited states that contain the same orbital

transition components of S1 were highlighted in red.

n-th Energy

(eV) Transition configuration (%)

Sn 1 3.4315 H-1→L (7.31), H→L (91.70)

Tn

1 3.1419 H-9→L+9 (2.66), H-1→L+1 (21.11), H-1→L+2 (55.44), H→L+2

(4.50), H→L+6 (5.93)

2 3.2368 H-5→L (2.66), H-3→L+1(5.75), H-2→L (18.25),

H-1→L (5.87), H→L (45.55), H→L+1 (8.34)

3 3.2496 H-5→L (2.69), H-3→L+1 (7.43), H-2→L (21.57),

H→L (42.42), H→L+1 (9.99)

4 3.4359 H-5→L (2.69), H-2→L (13.02), H-1→L (3.26),

H-1→L+1 (4.99), H→L+1 (58.52), H→L+5 (2.51)

5 3.4709 H-6→L (5.60), H-6→L+1 (2.53), H-6→L+4 (2.06),

H-5→L (3.40), H-5→L+1 (2.26), H-5→L+4 (2.26),

H-4→L+3 (4.23), H-3→L (42.16), H-3→L+4 (2.73),

H-2→L+1 (11.62), H-2→L+3 (3.16), H→L+1 (2.06)

6 3.5285 H-1→L (87.32), H→L (7.34), H→L+1 (2.00)

7 3.7712 H-9→L+2 (2.93), H-1→L+2 (7.29), H→L+2 (74.29), H→L+5 (2.04)

8 3.8321 H-1→L+1 (63.75), H-1→L+2 (17.54), H-1→L+5 (3.43), H→L+1

(5.18), H→L+2 (3.21)

9 3.9322 H-8→L (30.21), H-7→L (39.63), H-6→L (6.46),

H-4→L (12.79), H-3→L+1 (2.78)

10 3.9597 H-8→L (5.83), H-7→L (6.03), H-5→L (20.52),

H-5→L+1 (4.62), H-4→L (34.40), H-4→L+1 (4.95),

H-3→L (6.13), H-3→L+1 (6.23)





21

Table S5. The singlet and triplet excited states transition configurations of H-aggregated DPhCzT

dimer revealed by TD-DFT calculations. The matched excited states that contain the same orbital


n-th Energy


Sn 1 3.3454 H-3→L (2.88), H-2→L (4.29), H-1→L (86.53),

H→L (5.42)

Tn

1 3.1156 H-3→L+2 (5.59), H-3→L+5 (13.97), H-1→L (2.69),

H-1→L+5 (3.97), H-1→L+11 (34.49), H→L+2 (14.89),

H→L+5 (33.68)

2 3.1574 H-3→L+12 (23.09), H-2→L+3 (17.31), H-2→L+4 (48.27),

H-2→L+5 (2.73), H-1→L (3.19), H-1→L+3 (3.07),

H-1→L+4 (6.16), H→L+12 (2.72)

3 3.1674 H-3→L (3.06), H-2→L (5.32), H-1→L (77.09),

H→L (3.07)

4 3.2332 H-10→L (5.96), H-9→L+2 (2.93), H-8→L+1 (4.24),

H-6→L+1 (3.36), H-6→L+3 (3.88), H-5→L (3.49),

H-4→L+1 (19.06), H-3→L+3 (3.36), H-1→L+2 (9.15), H→L+1 (5.37),

H→L+3 (6.13)

5 3.2358 H-10→L (10.66), H-9→L+2 (6.24), H-8→L (4.41),

H-6→L+3 (2.05), H-5→L (7.07), H-4→L+1 (11.29),

H-3→L+3 (2.05), H-1→L+2 (15.41), H→L+3 (2.88)

6 3.2677 H-4→L+1 (4.84), H-3→L+1 (13.33), H→L+1 (69.97)

7 3.3830 H-10→L (3.20), H-3→L (4.49), H-1→L (3.52),

H-1→L+2 (20.94), H→L (50.62)

8 3.3861 H-8→L+1 (2.04), H-7→L+1 (2.16), H-6→L+1 (3.82),

H-4→L+1 (3.54), H-4→L+3 (3.10), H-3→L+1 (2.24),

H-2→L+1(3.31), H-1→L+1 (60.93), H→L+1 (2.70),

9 3.4099 H-10→L (7.46), H-8→L (2.81), H-5→L (3.71),

H-1→L+2 (29.11), H→L(32.67)

10 3.4615 H-4→L+1 (9.72), H-3→L (3.43), H-3→L+1 (4.07),

H-3→L+3 (22.18), H→L (2.31), H→L+3 (39.68)

11 3.4791 H-13→L (5.73), H-13→L+7 (2.49), H-12→L+6 (2.01),

H-11→L+2 (2.20), H-10→L(2.93), H-10→L+2 (5.93),

H-9→L (31.68), H-9→L+2 (2.75), H-8→L (4.01),

H-7→L+7 (2.72), H-6→L (4.91), H-5→L+2 (3.80),

H-3→L+1 (2.84)

12 3.4841 H-4→L+1 (2.84), H-3→L+1 (59.24), H-1→L+1 (11.46), H→L+1 (8.50)

13 3.5491 H-10→L+1 (2.67), H-8→L+1 (7.53), H-8→L+3 (2.68),

H-7→L+1 (2.57), H-6→L+1 (15.32), H-6→L+3 (2.29),

H-4→L+3 (3.09), H-3→L+1 (12.63), H-1→L+1 (20.64), H→L+1 (6.84)

14 3.6608 H-2→L+1 (89.83)





22

Table S6. The singlet and triplet excited states transition configurations of L-shaped aggregated

DPhCzT dimer revealed by TD-DFT calculations. The matched excited states that contain the

same orbital transition components of S1 were highlighted in red.

n-th Energy (eV) Transition configuration (%)

Sn 1 3.4690 H→L+1 (98.69)

Tn

1 3.1466 H-1→L+3 (22.69), H-1→L+5 (59.61), H→L+13 (6.51)

2 3.1504 H-3→L+2 (22.43), H-3→L+4 (58.19), H-2→L+11 (6.18)

3 3.2433 H-10→L+8 (2.96), H-9→L+1 (6.53), H-6→L+1 (2.34),

H-6→L+3 (3.51), H-6→L+10 (2.39), H-5→L+1 (5.37),

H-5→L+3 (3.82), H-5→L+12 (2.83), H-4→L+1 (35.46),

H-4→L+3 (7.40), H→L+3 (16.21)

4 3.2464 H-13→L (3.94), H-12→L+6 (3.14), H-11→L+7 (3.12),

H-8→L+2 (12.53), H-8→L+9 (2.18), H-7→L (46.33),

H-2→L+2 (14.98)

5 3.2769 H→L+1 (93.04)

6 3.3023 H-8→L (2.44), H-2→L (91.61)

7 3.4485 H-6→L+1 (3.86), H-5→L+12 (2.09), H-4→L+1 (19.31),

H-4→L+3 (4.64), H→L+3 (50.05)

8 3.4605 H-12→L (6.21), H-12→L+7 (3.43), H-11→L+9 (2.36),

H-8→L (21.83), H-7→L (9.20), H-7→L+2 (7.68),

H-7→L+6 (3.15), H-2→L+2 (29.65)

9 3.4771 H-12→L (4.21), H-8→L (20.85), H-7→L (4.10),

H-7→L+2 (4.46), H-2→L+2 (39.57)

10 3.4784 H-11→L+1 (3.65), H-11→L+8 (8.21), H-9→L+1 (5.78),

H-9→L+3 (2.61), H-6→L+1 (17.65), H-6→L+3 (2.83),

H-5→L+1 (16.38), H-5→L+10 (2.13), H-4→L+3 (4.26),

H→L+3 (19.06)

11 3.5748 H-1→L+1 (95.87)

12 3.6144 H-3→L (95.40)

13 3.6996 H→L (99.83)

14 3.728 H-1→L (99.87)

15 3.7405 H-19→L+4 (2.78), H-13→L+11 (4.41), H-2→L+2 (2.00),

H-2→L+4 (79.61)

16 3.7641 H-18→L+5 (2.93), H-9→L+13 (3.82), H→L+5 (81.33)

17 3.8042 H-5→L+1 (2.58), H-3→L+1 (4.88), H-2→L+1 (88.81)





23

Table S7. The singlet and triplet excited states transition configurations of cross-shaped

aggregated DPhCzT dimer revealed by TD-DFT calculations. The matched excited states that

contain the same orbital transition components of S1 were highlighted in red.

n-th Energy


Sn 1 3.3877 H-1→ L (95.73), H-1 → L+1 (2.26)

Tn

1 3.1367 H-1→L+13 (6.25), H→L+2 (22.22), H→L+5 (57.54)

2 3.1475 H-3→L+3 (21.91), H-3→L+4 (55.86), H-2→L+4 (2.59),

H-2 →L+12 (6.22)

3 3.2025 H-1→ L (91.27), H-1→ L+1 (2.49)

4 3.2404 H-13 → L+6 (2.52), H-12 → L (5.78), H-10 → L (6.30),

H-8→L+2 (3.78), H-7→L+2 (6.37), H-6→L (17.84),

H-5→L (12.34), H-1→L+2 (22.35)

5 3.2420 H-11→L+1 (4.58), H-9→L+8 (2.77), H-6→L+3 (3.70),

H-5→L+1 (3.14), H-5→L+3 (4.38), H-4→L+1 (37.85),

H-4→L+3 (3.88), H-2→L+3 (15.19)

6 3.2787 H-3→L+1 (3.65), H-2→L (3.84), H-2→L+1 (85.49)

7 3.4139 H-10→L (2.71), H-6→L (8.18), H-5→L (4.86),

H-1→L+2 (56.37), H-1→L+10 (2.11), H→L (8.21)

8 3.4468 H-4→L+1 (16.74), H-4→L+3 (3.90), H-3→L+3 (2.06),

H-2→L+3 (47.89)

9 3.4698 H-9→L+1(6.72), H-9 →L+8(4.62), H-7→L+1(3.78),

H-6→L+1(12.73), H-5→L+1 (17.47), H-5→L+3(2.01),

H-4→L+3(5.55), H-2→L+3(16.66)

10 3.4723 H-13→L (3.11), H-12→L+2 (2.22), H-8→L (5.22),

H-7→L (10.20), H-6→L (2.37), H-6→L+2 (2.55),

H→L (54.99)

11 3.4833 H-13→L (5.25), H-13→L+6 (5.35), H-12→L (5.85),

H-12→L+2 (3.92), H-8→L (6.66), H-7→L (14.61),

H-6→L+2 (2.33), H-5→L+2 (2.16), H-1→L+2 (4.81),

H→L (32.76)

12 3.5724 H-3→L (6.73), H-3→L+1 (86.09),

H-2→L+1 (3.18)

13 3.7123 H-2→L (92.28), H-2→L+1 (4.27)





24

Figure S15. The TD-DFT calculated singlet (S1) and triplet (Tn) states for the monomer and

corresponding H-aggregated dimer of (a) DEOPh, (b) DECzT, (c) CzDClT, and (d) DCzPhP,

respectively, based on single crystal diffraction data (Insets show the geometric arrangements of

the molecules). The triplet states marked in green contain the same transition configuration compositions as

that in S1. The gray solid triplet states are those levels with energy higher than ES1 + 0.3 eV or lower than ES1 -

0.3 eV.





25

Table S8. The singlet and triplet excited states transition configurations of DEOPh monomer



n-th Energy


Sn 1 4.7489 H-1→L+1 (9.22), H→L (90.32)

Tn

1 3.545 H-1→L (10.84), H→L (74.45), H→L+1 (14.46)

2 3.8614 H-1→L (21.97), H→L (24.40), H→L+1 (52.22)

3 4.6611 H-1→ L (66.88), H→L+1 (32.57)

4 5.9757 H-1→L+1 (98.48)

5 6.2261 H-7→L (4.68), H-2→L (90.61), H-1→L+8 (3.18)

6 6.9865 H-7→L+1 (2.13), H-2→L+1 (85.01), H→L+8 (11.14)

7 7.3776 H-6→L (5.79), H-3→L (92.56)

8 7.4689 H-3→L+2 (44.17), H→L+4 (20.02), H→L+5 (29.72)

9 7.5578 H→L+2 (6.91), H→L+3 (33.54), H→L+4 (42.45),

H→L+5 (11.09), H→L+6 (2.70)

10 7.6974 H→L+2 (10.79), H→L+3 (56.04), H→L+4 (25.76),

H→L+6 (3.53)

Table S9. The singlet and triplet excited states transition configurations of H-aggregated DEOPh



n-th Energy


Sn 1 4.3981 H→ L (99.86)

Tn

1 3.5368 H-3→ L (9.23), H-1→ L (71.12), H-1→ L+2 (12.61),

H→ L+1 (3.35)

2 3.5454 H-2→ L+1 (10.83), H-1→ L (3.99), H→ L (2.07),

H→ L+1 (66.15), H→ L+3 (14.87)

3 3.8565 H-3→ L (21.27), H-1→ L (23.07), H-1→ L+2 (52.53)

4 3.8727 H-2→ L+1 (19.73), H→ L+1 (28.25), H→ L+3 (48.52)

5 4.3969 H-2→ L+1 (3.78), H→ L (93.95)

6 4.6513 H-3→ L (54.92), H-2→ L (2.34), H-2→ L+1 (9.30),

H-1→ L+2 (28.03), H→ L+3 (3.95)

7 4.6614 H-3→ L (7.11), H-2→ L+1 (51.56), H-1→ L+2 (3.82),

H→ L (2.71), H→ L+3 (29.18)

8 5.0877 H-1→ L+1 (98.78)





26

Table S10. The singlet and triplet excited states transition configurations of DECzT monomer




Sn 1 4.3115 H-1 →L+3 (7.19), H→ L (84.36), H→L+1 (6.46)

Tn

1 3.1947 H-7→ L+5 (2.25), H-2→ L+1 (4.61), H-1→L (58.80),

H-1→L+1 (23.25), H→ L+3 (7.22)

2 3.6705 H-2→L+3 (3.18), H→L (81.63), H→L+1 (7.95)

3 3.7835 H-2→L+3 (7.73), H→L (13.12), H→L+1 (70.10)

4 4.1588 H-2→L (4.29), H-2→L+1 (2.49), H-1→L (27.95),

H-1→L+1 (58.71), H-1→L+4 (3.29)

5 4.3068 H-2→L+1 (23.48), H-2→L+4 (3.78), H-1→L (6.25),

H-1→L+1 (10.10), H→L+3 (52.32)

6 4.5686 H-8→L (2.36), H-7→L (11.94), H-6→L (4.85),

H-5→L+2 (2.32), H-4→L (2.30), H-4→L+1 (8.87),

H-2→L+3 (7.91), H-1→L+2 (3.12), H-1→L+3 (16.34), H-

1→L+5 (14.93), H→L+1 (8.45), H→L+4 (9.82)

7 4.6442 H-7→L (2.66), H-7→L+1 (7.30), H-6→L+1 (2.70),

H-4→L+1 (4.31), H-1→L+3 (70.35), H-1→L+5 (5.76),

H→L+1 (3.58)

8 4.7145 H-2→L (62.98), H-2→L+1 (9.59), H-1→L (2.52),

H-1→L+1 (4.29), H→L+2 (8.77), H→L+3 (2.81),

H→L+5 (5.99)

9 4.7794 H-5→L (3.83), H-4→L+2 (5.61), H-2→L (8.45), H→L+2

(76.50)

10 4.8826 H-7→L+1 (4.31), H-5→L+2 (10.95), H-4→L (45.31),

H-4→L+1 (5.27), H-1→L+3 (3.72), H-1→L+5 (8.88),

H→L+4 (3.29)





27

Table S11. The singlet and triplet excited states transition configurations of H-aggregated DECzT




Sn 1 4.1499 H-1→L+1 (3.25), H→L (90.74)

Tn

1 3.1947 H-5→L+2 (2.17), H-4→L+3(2.38), H-3→L (23.19), H-3→L+3 (3.77); H-2→

L+1 (21.96), H-2→ L+2 (7.96), H-1→ L (14.96), H-1→L+3 (2.51), H→L+1

(5.25), H→L+2 (2.40), H→L+6 (3.27)

2 3.1967 H-5→L+3 (2.09), H-4→L+2 (2.68), H-3→L+1 (17.40), H-3→L+2 (6.65), H-

2→L (30.55), H-2→L+3 (5.82), H-1→L+1 (9.89), H-1→L+2 (2.81), H-

1→L+6 (2.51), H→L (7.79), H→L+7 (3.19)

3 3.6749 H-3→L+1 (8.50), H-2→L (8.06), H-1→L+1 (24.27),nH→L (52.41)

4 3.6833 H-3→L (14.51), H-2→L+1 (3.77), H-1→L (37.89), H→L+1 (34.84)

5 3.7417 H-5→L+6 (4.59), H-4→L+7 (4.45), H-3→L+3 (8.29), H-2→L+2 (4.88), H-

1→L (2.74), H-1→L+3 (20.36), H→L+2 (41.72)

6 3.746 H-5→L+7 (4.14), H-4→L+6 (5.51), H-3→L+2 (11.75), H-2→L+3 (4.51), H-

1→L+2 (30.61), H→L (2.05), H→L+3 (28.90)

7 4.1726 H-4→L (4.24), H-3→L (5.92), H-3→L+3 (11.31), H-2→L+1 (2.61), H-

2→L+2 (28.29), H-1→L (9.20),H-1→L+3 (13.13), H→L+1 (6.28), H→L+2

(7.45)

8 4.1836 H-5→L (2.37), H-4→L+1 (2.71), H-3→L+1 (2.51), H-3→L+2 (24.23), H-

2→L (6.70), H-2→L+3 (20.48), H-1→L+1 (6.26), H-1→L+2 (16.53), H→L

(3.36), H→L+3 (7.49)

9 4.2648 H-5→L+3 (9.16), H-4→L+2 (13.80), H-3→L+6 (8.14), H-2→L (8.94), H-

2→L+7 (2.39), H-1→L+2 (4.45), H-1→L+6 (17.26), H→L (2.85), H→L+3

(2.59), H→L+7 (19.17)

10 4.2745 H-5→L+2 (9.89), H-4→L+3 (9.92), H-3→L (2.29), H-3→L+3 (5.05), H-

3→L+7 (6.07), H-2→L+2 (7.66), H-2→L+6 (2.88), H-1→L (5.87), H-1→L+7

(13.71), H→L+1 (2.46), H→L+6 (24.23)

11 4.3578 H-3→L (29.51), H-2→ L+1 (8.18), H-1→L (14.37), H→ L+1 (42.68)

12 4.3587 H-3→ L+1 (9.70), H-2→ L (19.42); H-1→ L+1 (48.42), H→ L (19.18)

13 4.4195 H-3→ L+1 (51.66), H-2→ L (20.87), H-1→ L+1 (6.24), H→ L (10.46)

14 4.4236 H-3→ L (19.40), H-2→ L+1 (56.42), H-1→ L (10.87), H→ L+1 (4.06)

15 4.5587 H-15→ L +1 (5.31), H-14→ L (5.96), H-9→ L (2.31), H-9→ L+3 (2.88), H-

8→ L+2 (3.76), H-5→ L+6 (3.64),H-4→ L+7 (3.59), H-3→ L+7 (6.09), H-3→

L+8 (2.00), H-3→ L+10 (3.45), H-2→ L+6 (8.25), H-2→ L+11 (5.03), H-1→

L+7 (4.85), H-1→ L+8 (2.33), H-1→ L+10 (2.56), H→ L+2 (10.89), H→ L+6

(2.35), H→ L+9 (3.54)





28

Table S12. The singlet and triplet excited states transition configurations of CzDClT monomer



n-th Energy


Sn 1 3.7902 H→L (16.46), H→L+1 (81.31)

Tn

1 3.1022 H-3→L+6 (3.24), H-2→L+2 (2.52), H-2→L+5 (2.02),

H-1→L+3 (6.43), H→L (3.50), H→L+1 (36.68),

H→L+2 (42.78)

2 3.2953 H-2→L+3 (3.23), H-1→L (8.93), H-1→L+1 (81.51)

3 3.5983 H-7→L (2.14), H-1→L (85.89), H-1→L+1 (9.44)

4 3.7396 H-2→L+2 (3.23), H-1→L+3 (2.16), H→L (8.11), H→L+1

(46.46), H→L+2 (35.79)

5 3.837 H-1→L+2 (5.78), H→L (78.37), H→L+1 (11.22)

6 3.8868 H-3→L+2 (3.24), H-2→L+3 (6.73), H-1→L+1 (3.17),

H-1→L+2 (71.96), H→L (8.31)

7 4.2355 H-2→L (3.06), H-2→L+1 (31.11), H-2→L+2 (6.87),

H-2→L+5 (5.75), H-1→L+3 (35.34), H→L+2 (14.64)

8 4.463 H-7→L+1 (14.37), H-6→L (15.58), H-4→L (8.62),

H-3→L+2 (6.85), H-2→L (4.97), H-2→L+3 (8.35),

H-1→L+2 (4.91), H-1→L+5 (9.33), H→L+3 (8.82), H→L+6

(7.96)

9 4.5273 H-4→L (64.08), H-4→L+1 (5.69), H-3→L+2 (2.49),

H-2→L+3 (2.06), H-1→L+5 (2.72), H→L+3 (5.73),

H→L+6 (3.60)

10 4.5515 H-2→L (2.82), H-2→L+1 (37.72), H-2→L+2 (42.31),

H-1→L+3 (5.24), H-1→L+6 (4.14), H→L+2 (3.56)





29

Table S13. The singlet and triplet excited states transition configurations of H-aggregated CzDClT




Sn 1 3.6415 H-1→L (42), H→L+1 (54)

Tn

1 3.0942 H-3→L (2.35), H-3→L+5 (6.35), H-3→L+7 (2.16),

H-2→L+1 (2.96), H-2→L+4 (4.21)H-2→L+6 (2.42),

H-1→L+1 (8.97), H-1→L+3 (6.65), H-1→L+4 (17.90), H→L(9.87), H→L+2 (6.07),

H→L+5(14.32)

2 3.1017 H-3→L+4 (9.03), H-2→L+5 (7.18), H-1→L (9.48),

H-1→L+2(5.18), H-1→L+5 (14.32), H→L+1 (13.30),

H→L+3 (7.71), H→L+4 (10.01)

3 3.2566 H-3→L+1 (8.11), H-3→L+3 (7.75), H-2→L (7.89),

H-2→L+2 (10.87), H-1→L (13.77), H-1→L+2 (12.47),

H→L+1 (15.68), H→L+3 (12.98)

4 3.2709 H-3→L (9.86), H-3→L+2 (9.09), H-2→L+1 (11.47),

H-2→L+3 (9.65), H-1→L+1(12.47), H-1→L+3 (9.14),

H→L (13.77), H→L+2 (14.89)

5 3.5301 H-3→L (6.75), H-3→L+2 (2.40), H-2→L+1 (9.02),

H-2→L+3 (2.59), H-1→L+1 (16.32), H-1→L+3 (7.39),

H→L (36.26), H→L+2(14.40)

6 3.5394 H-3→L+1 (6.29), H-3→L+3 (2.24), H-2→L (10.57),

H-2→L+2 (2.98), H-1→L (20.71), H-1→L+2 (9.71),

H→L+1 (25.80), H→L+3 (16.21)

7 3.7003 H-2→L+4 (5.02), H-1→L+1 (40.48), H-1→L+3 (3.04),

H-1→L+4 (5.18), H→L+2 (23.33), H→L+5 (12.50),

8 3.7080 H-3→L+4 (5.01), H-2→L+5 (5.09), H-1→L (23.90),

H-1→L+2 (14.05), H-1→L+5 (11.49), H→L+3 (19.04),

H→L+4 (8.45)

9 3.7272 H-3→L (7.32), H-3→L+2 (3.45), H-3→L+5 (5.92),

H-2→L+3 (5.81), H-1→L+1(12.10), H-1→L+3 (13.36),

H-1→L+4 (9.07), H→L (29.88), H→L+2 (4.54)

10 3.7397 H-3→L+3 (2.83), H-2→L+2 (2.91), H-1→L (24.75),

H-1→L+2 (28.58), H-1→L+5 (2.82), H→L+1 (30.32),

H→L+3 (3.41)

11 3.8023 H-3→L+1 (17.87), H-3→L+3 (3.20), H-3→L+4 (4.23),

H-2→L (28.19), H-2→L+2 (10.43), H-2→L+5 (2.67),

H-1→L+2 (11.46), H-1→L+5 (3.07), H→L+1 (6.00), H→L+3 (3.76), H→L+4 (3.13)

12 3.8065 H-3→L (9.22), H-3→L+2 (9.34), H-2→L+1 (46.88),

H-2→L+3 (2.32), H-1→L+1 (3.27), H-1→L+4 (2.14),

H→L (2.53), H→L+2 (21.17)

13 3.8105 H-3→L (22.86), H-2→L+3 (2.49), H-1→L+3 (54.47), H→L+2 (9.40), H→L+5 (2.38)

14 3.826 H-3→L+1 (29.49), H-3→L+3 (2.78), H-2→L (19.56),

H-2→L+2 (8.08), H-2→L+5 (3.42), H-1→L+2 (10.43),

H→L+1 (3.52), H→L+3 (11.32), H→L+4 (5.69)

15 3.8378 H-5→L+6 (2.31), H-4→L+7 (2.54), H-3→L+1 (4.01),

H-3→L+4 (11.25), H-2→L (10.91%, H-2→L+5 (14.12),

H-1→L+2 (2.54), H-1→L+5 (9.33), H→L+3 (19.22), H→L+4 (14.95)

16 3.856 H-4→L+6 (2.01), H-3→L (14.12), H-3→L+5 (12.26),

H-2→L+3 (2.95), H-2→L+4 (14.84), H-1→L+4 (15.49),

H→L (3.40), H→L+5 (21.24)

17 3.9382 H-3→L+1 (16.94), H-3→L+3 (23.85), H-2→L+2 (46.56)

18 3.9397 H-3→L (7.07), H-3→L+2 (40.21), H-2→L+1 (7.17),

H-2→L+3 (35.35)

19 3.999 H-3→L (15.42), H-3→L+2 (30.02), H-2→L+1 (13.98),

H-1→L+3 (32.61)

20 4.0059 H-3→L+1 (12.95), H-3→L+3 (50.05), H-2→L (14.80),

H-2→L+2 (12.09), H-1→L+2 (2.65), H→L+3 (2.41)





30

Table S14. The singlet and triplet excited states transition configurations of H-aggregated DCzPhP

monomer revealed by TD-DFT calculations. The matched excited states that contain the same

orbital transition components of S1 were highlighted in red.


Sn 1 4.0955 H→L (94.57)

Tn

1 3.2151 H-3→L+4 (2.64), H-2→L (6.09), H-2→L+2(3.42),

H-1→L (38.12), H-1→L+1 (3.60), H-1→L+2 (23.38),

H→L+4 (3.65)

2 3.2384 H-3→L+5 (3.81), H-2→L (9.83), H-2→L+1 (56.67),

H-1→L+1 (7.91), H→L+5 (4.42)

3 3.5502 H-4→L+2 (4.45), H-3→L (2.61), H-3→L+1 (11.07),

H-3→L+2 (4.42), H→L (56.56), H→L+1 (3.36),

H→L+2 (2.10)

4 3.5913 H-3→L (19.99), H-3→L+1 (8.40), H→L+1(41.15),

H→L+2 (12.16), H→L+3 (2.21)

5 3.6273 H-10→L+2 (3.41), H-7→L+1 (2.11), H-7→L+3 (16.66),

H-4→L (19.02), H-4→L+1 (3.93), H-4→L+2 (23.04),

H-3→L+2 (2.34), H→L+1 (4.30), H→L+2 (11.82)

6 4.0641 H-7→L+3 (4.33), H-3→L+7 (2.22), H-1→L (2.43),

H→L (7.32), H→L+1 (15.28), H→L+2 (33.07),

H→L+4 (8.25), H→L+7 (2.05)

7 4.1391 H-9→L (2.32), H-6→L+4 (3.98), H-5→L+4 (4.52),

H-3→L+1 (2.27), H-3→L+4 (13.65), H-1→L (2.08),

H-1→L+8 (2.60), H→L (7.42), H→L+1 (3.53),

H→L+4 (23.25), H→L+7 (5.39)

8 4.2219 H-6→L+1 (4.12), H-6→L+7 (2.07), H-5→L (5.47),

H-5→L+1 (3.19), H-5→L+6 (2.41), H-3→L+4 (2.03),

H-3→L+5 (11.23), H-3→L+6 (2.89), H-2→L (2.85),

H-2→L+1 (6.08), H-1→L (8.23), H→L+2 (4.00),

H→L+5 (24.82), H→L+6 (4.20)

9 4.2346 H-6→L (5.43), H-6→L+6 (4.34), H-5→L+1(2.43),

H-5→L+2 (2.32), H-3→L+5 (8.05), H-3→L+6 (6.17)

H-2→L (5.48), H-1→L (3.34), H→L+2 (2.89),

H→L+3(5.56), H→L+4 (2.14), H→L+5 (4.49),

H→L+6 (15.88), H→L+7 (2.17)

10 4.2689 H-9→L+1 (3.02), H-8→L+1(3.21), H-7→L+3 (3.55),

H-6→L+5 (3.57), H-5→L+5 (4.63), H-3→L (2.88),

H-3→L+2 (8.59), H-3→L+7 (7.03), H-2→L+9 (3.95),

H→L (10.20), H→L+2 (11.87), H→L+6 (3.15),

H→L+7 (6.16)

11 4.3909 H-7→L+2 (3.80), H-7→L+3 (3.29), H-4→L+1 (3.93),

H-4→L+3 (14.25), H-3→L+1 (8.07), H-3→L+2 (2.75),

H→L+1 (4.28), H→L+3 (36.38)

12 4.4213 H-6→L+1 (2.09), H-5→L+1 (3.33), H-3→L (4.87),

H-2→L (41.54), H-2→L+1 (8.57), H-2→L+2 (10.24),

H-2→L+7 (4.09), H-1→L (5.14), H-1→L+1 (3.25),

H→L+1 (2.37)





31

Table S15. The singlet and triplet excited states transition configurations of H-aggregated DCzPhP




Sn 1 3.9460 H-2→L+1 (12.06), H→L (83.03)

Tn

1 3.2006 H-3→L+5 (20.61), H-3→L+7 (4.62), H-1→L+4 (48.23), H-1→L+6 (3.17), H→L+12 (4.11)

2 3.2203 H-6→L+1 (3.21), H-5→L (2.09), H-3→L+4 (25.14), H-2→L+12 (2.08), H-1→L+5 (33.52), H-

1→L+7 (7.02), H→L+14 (2.89)

3 3.2239 H-7→L+1 (12.02), H-6→L (29.50), H-6→L+1 (2.49), H-6→L+3 (3.97), H-5→L+1 (19.13), H-

5→L+2 (2.27), H-4→L+8 (2.33)

4 3.2244 H-7→L (10.87), H-6→L (2.76), H-6→L+1 (26.93), H-6→L+2 (3.51), H-5→L (17.08), H-5→L+1

(2.22), H-5→L+3 (2.09), H-4→L+9 (2.12), H-3→L+4 (2.32), H-1→L+5 (3.09)

5 3.5235 H-7→L (7.42), H-5→L (5.13), H-4→L+1 (18.47), H-2→L (23.42), H→L+1 (15.80), H→L+4 (2.46)

6 3.5242 H-7→L+1 (7.84), H-5→L+1 (5.34), H-4→L (18.85), H-2→L+1(22.30), H→L (17.34)

7 3.5898 H-9→L+3 (2.42), H-7→L (2.37), H-4→L+1 (3.70), H-2→L+3 (3.27), H-2→L+5 (14.46), H-2→L+7

(2.47), H→L+2 (8.39), H→L+4 (32.66)

8 3.6005 H-15→L+6 (2.71), H-9→L+1 (2.50), H-9→L+2 (5.73), H-8→L (2.04), H-8→L+3 (5.29), H-4→L

(3.26), H-4→L+3 (2.07), H-2→L+2 (8.74), H-2→L+4 (12.99), H→L+3 (4.62), H→L+5 (19.95),

H→L+7 (2.38)

9 3.6267 H-20→L+2 (2.05), H-16→L+6 (2.17), H-15→L+5 (2.05), H-15→L+7 (5.33), H-14→L+6 (4.16), H-

9→L (3.75), H-9→L+3 (15.31), H-8→ L+1 (3.16), H-8→L+2 (13.76), H-4→L+2 (3.03), H-2→L+3

(4.04), H-2→L+5 (3.45), H→L+4 (12.15), H→L+6 (2.07)

10 3.6323 H-15→L+6 (4.77), H-14→L+7 (3.05), H-9→L+1 (2.52), H-9→L+2 (11.73), H-8→L (2.36), H-

8→L+3 (10.69), H-2→L+4 (12.38), H→L+3 (2.01), H→L+5 (14.62), H→L+7 (4.68)

11 3.9696 H-4→L (4.37), H-2→L+2 (8.97), H-2→L+4 (4.21), H→L (39.09), H→L+3 (13.08), H→L+5 (5.81),

H→L+15 (2.20)

12 3.9778 H-4→L+1 (3.82), H-2→L+3 (11.12), H→L+1 (31.13), H→L+2(17.15), H→L+4 (8.44)

13 4.0346 H-1→L (88.58)

14 4.0475 H-1→L+1 (72.26), H→L+1 (7.37), H→L+2 (2.52), H→L+3 (3.28)

15 4.0476 H-2→L (8.12), H-2→L+3 (2.49), H-1→L+1 (13.25), H→L+1 (39.35), H→L+2 (13.57)

16 4.0643 H-2→L+1 (9.76), H-2→L+2 (6.81), H-1→L+1 (6.49), H→L (33.00), H→L+3 (20.90)

17 4.1236 H-13→L+9 (2.78), H-12→L (2.03), H-12→L+8 (3.51), H-7→L+8 (8.12), H-6→L+1 (2.47), H-

6→L+9 (2.14),H-4→L+9 (9.31), H-2→L (8.10), H-2→L+8 (9.02), H→L+9(5.17)

18 4.1240 H-13→L+8 (2.60), H-12→L+9 (3.34), H-7→L+9 (7.71), H-6→L (2.38), H-6→L+8 (2.01), H-4→L+8

(9.06),H-2→L+1 (10.13), H-2→L+9 (8.28), H→L+8 (5.15)

19 4.1804 H-3→L (5.08), H-3→L+3 (2.74), H-2→L+14 (4.89), H-1→L+1 (2.73), H-1→L+2 (43.13), H-1→L+4

(3.57), H-1→L+13 (2.51), H→L+12 (11.78)

20 4.1853 H-11→L+5 (2.78), H-10→L+4 (3.59), H-3→L+4 (2.77), H-2→L(3.93), H-2→L+5 (4.35), H-2→L+7

(2.16), H-2→L+12 (10.66), H-1→L(2.01), H-1→L+3 (2.13), H-1→L+5 (12.66), H→L+4 (5.48),

H→L+10 (2.21), H→L+13 (6.03), H→L+14 (8.90)

21 4.2031 H-13→L (2.54), H-12→L+1 (2.56), H-5→L+1 (7.18), H-4→L (3.40), H-4→L+8 (3.71), H-4→L+11

(4.58), H-2→L+1 (35.03), H-2→L+10 (3.56)

22 4.2063 H-13→L+1 (2.30),H-12→L (2.41), H-5→L (7.15), H-5→L+11 (2.05), H-4→L+1 (3.22), H-4→L+9

(3.39), H-4→L+10 (4.88), H-2→L (30.21), H-2→L+8 (2.20), H-2→L+11 (2.85), H→L+2 (6.48)

23 4.2365 H-3→L+1 (5.48), H-3→L+2 (6.06), H-2→L (2.32), H-1→L+3(62.03)

24 4.2370 H-11→L+4 (3.22), H-10→L+5 (3.30), H-2→L+13 (6.73), H-2→L+14 (2.39), H-1→L+2 (17.26), H-

1→L+4 (6.23), H→L+3 (2.33), H→L+5 (2.23), H→L+7 (2.79), H→L+12 (13.20)

25 4.2844 H-11→L+14 (2.39), H-10→L+12 (2.37), H-7→L+1 (2.22), H-4→L+3 (2.35), H-4→L+11 (2.62), H-

3→L (4.30), H-2→L+1 (3.40), H-2→L+13 (2.25), H-2→L+14 (2.81), H-1→L+2 (13.59), H-1→L+4

(5.04), H-1→L+19 (2.60), H→L+3 (2.64), H→L+5 (3.18), H→L+12 (2.22), H→L+15 (6.35)

26 4.2847 H-7→L (9.38), H-6→L+1 (3.90), H-5→L+11 (3.90), H-4→L+1 (5.73), H-4→L+10 (6.54), H-2→L

(14.38), H-2→L+5 (5.77), H-2→L+11 (2.18), H-1→L+3 (3.94), H→L+6 (2.98)





32

As evident from Figure S15 and Tables S4-15, DPhCzT molecules have more available transition

channels with superimposed transition configurations for facile intersystem crossing from S1 to Tn than

DEOPh, DECzT, CzDClT, and DCzPhP molecules, thereby affording the most intense ultralong

luminescence among all molecules under investigation.

To convince the existence of energy splitting induced by H-aggregation, we further conducted TD-

DFT calculations and estimated the singlet transition dipole moments of the ultra-long emission

compounds (Table S16). The high values of the transition dipole moments provide solid basis for H-

aggregate-induced energy splitting.

Table S16. TD-B3LYP/6-31G(d) calculated singlet transition dipole moments of the ultralong

phosphorescent molecules.

Compound Transition dipole moment (Debye) DPhCzT 2.065 DEOPh 1.657 DECzT 1.474 CzDClT 2.027 DCzPhP 0.666

For organic dyes with low molecular weights, the exciton binding energy is typically in the range of

several hundred meVs due to their tightly-bounded nature of excitons (Frenkel excitons).30 Thus the

dissociation of such type of excitons to free electrons and holes is difficult to occur at room temperature.

To obtain the binding energies (S1Eb and T1Eb) of singlet and triplet excitons, we can use the following

formulas: 1

1S

b g SE E E 1

1T

b g TE E E

where Eg is the HOMO-LUMO energy bandgap, and ES1 and ET1 are the excitation energies from the

ground state to the lowest singlet and triplet excited states, respectively.31 The HOMO and LUMO

energy levels can be measured by cyclic voltammetrics (CV), while ES1 and ET1 can be derived from the

shortest emission peak wavelength of the fluorescence and phosphorescence. The results show that the

singlet and triplet exciton binding energies of DPhCzT are around 0.25 and 0.26 eV, respectively. With

such high exciton binding energies, the dissociation of excitons can hardly take place at room

temperature.

VI. Experimental validation of triplet excited states

The existence of triplet states of DPhCzT molecules in both solution and aggregated states was

detected by photodegradation of anthracene-9,10-diyl-bis-methylmalonate (ADMA). The basic

detection mechanism is shown in Figure S16. Briefly, upon photoexcitation the energy transfer (ET)





33

between the triplet state of the material and the ground state of molecular oxygen (3O2) can lead to the

generation of an electronically excited state of molecular oxygen, i.e. singlet oxygen (1O2). Then, ADMA

is utilized to detect the generated 1O2 as a chemical trap by which this process can be quantitatively

monitored using a UV-vis spectrophotometer.32 As a result, if there are triplet states and 1O2 generated in

the system upon photo-excitation, the characteristic absorption peaks of ADMA (260, 358, 378, and 399

nm) will be gradually decreased and eventually disappeared. To validate our hypothesis, the experiments

were conducted on both well dispersed DPhCzT molecules (20 μM) in THF and their aggregated states

induced in a mixed solution of H2O and THF (VH2O :VTHF = 80 : 20) containing ADMA (50 μM) and

dissolved molecular oxygen. The absorption spectra were recorded every 30 min under irradiation of 330

nm UV light. Meanwhile, the control experiment with only ADMA in the mixed solution was also

designed. As shown in Figure S17, there is a negligible change in the absorption spectra of ADMA after

excitation for 1.5 h. By comparison, in the present of DPhCzT, the characteristic absorbance of ADMA

gradually decreased with the increasing illumination time from 0 to 1.5 h, indicating that the generation

of the triplet-excited states upon photo-excitation of this purely organic compound. The enhanced

photodegradation of ADMA in the presence of aggregated DPhCzT molecules is consistent with our

theoretical calculation that suggest the existence of more singlet-to-triplet transition channels for

facilitated intersystem crossing in aggregated states than in non-aggregated states.

Figure S16. Detection of triplet-excited states in DPhCzT molecules using ADMA. a, The mechanism

of detecting triplet excitons through the generation of a singlet oxygen (1O2) species that can be detected using

ADMA. b, Molecular structure of the ADMA molecules used for detecting the singlet oxygen species.





34

Figure S17. Absorption spectra of ADMA in THF/water (v/v; 20/80) under irradiation at 330 nm for

different periods of time (0, 30, and 90 min).

VII. Understanding molecular aggregation

The self-association of dyes in solution or in the solid state is a frequently encountered phenomenon in

dye chemistry owing to intermolecular van der Waals-like attractive forces between the molecules. The

aggregates exhibit notable changes in the absorption band as compared to the monomeric species. From

the spectral shifts, various aggregation patterns of the dyes in different media can be identified. The

bathrochromically shifted J-bands and hypsochromically shifted H-bands of the aggregates have been

explained in terms of molecular exciton coupling theory, i.e., coupling of transition moments of the

constituent dye molecules. The aggregates that exhibit H-bands in their absorption spectra are called H-

aggregates whereas J-aggregates have the characteristics of J-bands. They can be detected by

absorption spectra or single crystal analysis.33-35

H-aggregates were classically identified via their blue-shifted H-bands in their absorption spectra.

Taking DPhCzT as a typical example, a new blue-shifted absorption peak around 320 nm gradually

emerges when the H2O content increases from 1 to 20% (Figure S18), indicating that H-aggregates are

formed during the aggregation of DPhCzT molecules.





35

Figure S18. The absorption spectra of DPhCzT (20 μM) measured with increasing water content

from 1 vol% to 20 vol % in methanol.

According to the molecular excition theory, the exciton splitting energy (∆ε) in the case of dimer is

given by: 2

1 23

2(cos 3cos cos )

uv

M

r

where M is the electric dipole transition moment, α is the angle between the transition moments of the

two molecules in the dimer, and and are the angles between transition moments of the two

molecules and the interconnection of the centres.35,36 As a result, when ∆ε > 0, it is H-aggregation, when

∆ε < 0, J-aggregation forms.

Extensive studies on the correlations between photophycial properties and aggregation forms have

proposed that the H-aggregated states can be divided into four types35: parallel model, oblique model,

coplanar inclined model and non-planar model (Figures S19, a-d). The exciton splitting in co-planar

inclined model (α= 0 and = = ) is given by a simplified formula as follows:

2

23

2(1 3cos )

uv

M

r

where ∆ε is the exciton splitting energy, M is the transition moment for the singlet-singlet transition in

the monomer, and is the angle of coplanar transition dipoles inclined to interconnected axis. It is

evident that for the value of = 54.7o, the exciton splitting is zero, i.e., the dipole-dipole interaction is





36

zero for this type of orientation in transition moments, regardless of the intermolecular distance (ruv).

As a result, when is higher than 54.7o, it is H-aggregation with positive exciton splitting energy (∆ε),

while J- aggregates form in the case of 54.7o.35,37

The molecular aggregates of DPhCzT, DECzT, CzDClT, DCzPhP, and DEOPh were further

investigated by single crystal structure analyses using the molecular excition theory. From Figures S19,

the aggregation states of DPhCzT, DECzT, CzDClT, and DCzPhP belong to coplanar inclined model,

judged from the solid-state single crystal structures (Figure S20 and Table S17). The angles () between

the transition dipoles and the interconnected axis are 80.9o for DPhCzT, 70.1o for DECzT, 71.8o for

CzDClT, and 83.2o for DCzPhP, respectively, which are well above the critical angle (54.7 o) of H-

aggregation. DEOPh belongs to a variant of non-planar model with an exciton splitting energy (∆ε) of

higher than zero, as calculated from the angles between the transition moments in the two molecules (α = 102.4o) and between the transition dipoles and the interconnected axis (θ1= 84.0o and θ2= 149.5o). The

positive exciton splitting energies (∆ε) calculated on the basis of single crystal structures clearly show

the H-aggregation in solid states of DPhCzT, DECzT, CzDClT, DCzPhP, and DEOPh.

Figure S19. Schematic representation of different models of H-aggregation. a, Parallel model. b,

Oblique model. c, Co-planar inclined model. d, Non-planar model. e and f, Single crystal structures of DECzT,

CzDClT, DCzPhP and DEOPh showing the evidence of H-aggregate formation in these molecules. The angle

between the transition dipoles and the interconnected axis is indicated by θ.





37

Figure S20. Single-crystal unit cells of DPhCzT, DECzT, CzDClT16, DEOPh, and DCzPhP.

Table S17. Structure data of DPhCzT, DEOPh, DECzT, CzDClT and DCzPhP single crystalsa

Name DPhCzT DEOPh DECzT CzDClTb DCzPhP

Formula C27H18N4 C10H14O2 C19H18N4O2 C15H8Cl2N4 C30H21N2P

Wavelength (Å) 0.71073 0.71073 0.71073 0.71073 0.71073

Space Group P 21/c P 21 C2/c C2/c P-1

Cell Lengths (Å) a 5.124 (10),

b 17.258 (6),

c 22.113 (9)

a 7.139 (6),

b 7.608 (6),

c 9.483 (8)

a 16.972 (10),

b 10.790 (6),

c 9.5410 (10)

a 20.280(3),

b 8.0726 (14),

c 16.005 (3)

a 9.659(12),

b 10.339 (12),

c 12.812 (13)

Cell Angles (o) α 90.00,

β 95.60 (11),

γ 90.00

α 90.00,

β 110.09 (14),

γ 90.00

α 90.00,

β 108.70 (11),

γ 90.00

α 90.00,

β 98.94 (3),

γ 90.00

α 68.63 (13),

β 85.29 (14),

γ 72.21 (14)

Cell Volume (Å3) 1946.13 483.7 (7) 1654.93 2588.3(8) 1134(2)

Z 4 2 4 8 2

Density (g/cm3) 1.36 1.14 1.34 1.62 1.29

F(000) 832.0 180.0 704 1280 460.0

hmax, kmax, lmax 6, 21, 26 9, 9, 12 20, 12, 11 18, 10, 21, 11, 12, 15

Tmin, Tmax - 0.988, 0.990 0.988, 0.989 0.792, 0.929 0.980, 0.983

aThe obtained crystal structures have been deposited at the Cambridge Crystallographic Data Centre and allocated the deposition number: 1022442 (DPhCzT), 1022443 (DECzT), 1022444 (DCzPhP), and 1022445 (DEOPh). bSee ref. 38.





38

VIII. Comparative photoluminescent studies of DECzT, DEOPh, DPhCzT, CzDClT, and

DCzPhP

The detailed photoluminescent properties of the as-prepared compounds were measured to validate

our proposed mechanism underlying the ultralong organic phosphorescence. The green, yellow, and red

colors of ultralong phosphorescence were successfully observed in DEOPh, DPhCzT, CzDClT, and

DCzPhP powders (Figures S21 and S22), respectively. The availability level of the S1→Tn transition

channels in these phosphorescent moleculs is arranged in the following order: DPhCzT > CzDClT >

DCzPhP > DECzT > DEOPh (Table S4-15). Note that DPhCzT with strongest phosphorescence has the

most S1→Tn transition channels, while weakly emitting DEOPh has the least transition channels

available.

Figure S21. Lifetime decay profiles of ultralong phosphorescence of DEOPh, DECzT, CzDClT, and

DCzPhP powders under ambient conditions. a-d, Lifetime decay profiles of ultralong phosphorescence of

DEOPh (515 and 550 nm), DECzT (529 and 574 nm), CzDClT (543 and 591 nm), and DCzPhP (587 and 644 nm)

powder. DEOPh was excited at 254 nm while other compounds were excited at 365 nm.





39

Figure S22. Photographs of the five ultralong phosphorescence materials taken at different time

intervals before (first row) and after (succeeding rows) turn-off of the excitation under ambient

conditions. Note that DEOPh was excited at 254 nm while other compounds were excited at 365 nm. The

photographs were taken under identical conditions. The strongest ultralong phosphorescence was observed

from DPhCzT.

On the basis of the measured fluorescence and phosphorescence efficiencies and the emission lifetimes

of these molecules, the radiative and nonradiative decay rates can be calculated following the standard

methods reported previously.39-41 As shown in Table S18, it can be easily found that the nonradiative

decay rates for both fluorescence and ultralong phosphorescence are nearly two orders of magnitude





40

faster than radiative decay rates. The radiative (krPhos) and nonradiative decay (knrPhos) rates of the

ultralong phosphorescence are 108 times lower than that of the fluorescence, due to the spin-forbidden

feature of the T1→S0 transition. The intersystem crossing rates (kisc) of these molecules are comparable

to their corresponding radiative decay rates (krFluo), indicating an efficient intersystem crossing process

to produce sufficient triplet excitons responsible for the ultralong phosphorescence.

Table S18. Dynamic photophysical parameters of the ultralong organic phosphorescent molecules.

Compound Wavelength (nm)

Fluorescence Ultralong Phosphorescence τFluo

(ns) φ (%)

krFluo

(s-1)a knrFluo

(s-1)b kisc

(s-1)c

τPhos (s)

φ(%)

krPhos

(s-1)d knrPhos

(s-1)e DPhCzT 440 4.4 4.35 9.9×106 2.2×108 2.8×106 - - - -

535 - - - - - 1.06 1.25 1.2×10-2 0.93 DEOPh 332 2.8 9.1 3.3×107 3.2×108 1.1×106 - - - - 515 - - - - - 0.71 0.3 4.2×10-3 1.4 CzDClT 408 2.0 13.1 6.6×107 4.3×108 1.1×107 - - - -

543 - - - - - 0.47 2.1 4.5×10-2 2.1 DECzT 393 5.5 20.5 3.7×107 1.4×108 1.1×106 - - - -

529 - - - - - 1.28 0.6 4.7×10-3 0.78 DCzPhP 406 6.6 4.89 7.4×106 1.4×108 1.2×105 - - - -

587 - - - - - 0.231 0.08 3.5×10-3 4.3

a /Fluor Fluo Fluok ; b (1 ) /Fluo

nr Fluo Phos Fluok ; c /isc Phos Fluok ; d /Phosr Phos Phosk ; e (1 ) /Phos

nr Phos Phosk .

Figure S23. Lifetime decay profiles of the fluorescent bands of DEOPh (332 nm), CzDClT (408

nm), DECzT (393 nm) and DCzPhP (406 nm) powders at 300 K.





41

IX. Data encryption applications

The application of the ultralong phosphorescence in data encryption was demonstrated by writing the

number of “2014”. The detailed synthesis and structure characterization of the blue fluorescent

conjugated copolymer of 9,9-dioctylfluorenes-co-2,2’-bis(octyloxy)-1,1-binaphthyl (PFB, Figure S24)

can be found in our previous report.42 The “2014” was written on a filter paper using a mixture of

DPhCzT powder and ALOE VERA gel (c.a. 30 mg/mL). After ALOE VERA gel is volatilized, the

number of “8888” was painted over the pattern of “2014” using a dichloromethane solution of PFB (10

mg/mL). The “2014” was encrypted in “8888” under the excitation of 365 nm UV-light, however, when

the UV-light is turned off, the encryption of “2014” could be switched off. All the experiments were

performed under ambient conditions at room temperature.

Figure S24. Photoluminescence of PFB film under ambient conditions (300 K). a, Steady-state PL

spectrum of the PFB film under excitation at 380 nm (Inset is the molecular structure of PFB). b, lifetime decay

profile of the fluorescent emission of the film at 440 nm. The excitation wavelength of PFB film was fixed at 380

nm.

X. Supplementary videos

The supplementary videos were recorded by Nikon D90 in dark under ambient conditions.

SV1. To further validate the inertness of the ultralong organic phosphorescence to oxygen, we

carried out control experiments of DPhCzT powder under different atmospheres, including oxygen (O2),

air, and argon (Ar). The samples were kept in tubes under different atmospheres for three days. It was

found that there is no obvious difference in the organic phosphorescence observed in three different

atmospheres after the excitation at 365 nm was turned off. The lack of emission quenching by oxygen

can be attributed to the stabilization and pretection of the triplet excitons in aggregated structures. In

additon, to test the effects of oxygen on the conventional triplet emission in solution and solid states

under ambient conditions, control experiments on a typical organic phosphor of Ir(ppy)3 in

dichloromethane solution and in solid state under a nitrogen or oxygen atmosphere were carried out.





42

The solution of Ir(ppy)3 showed green emission under 365 nm excitation under amibient conditions.

After charging the solution with oxygen, phosphorescence quenching was clearly observed. However, the

oxygen atmosphere was found to have a limited quenching effect on the emission of Ir(ppy)3 in powder

form.

SV2. To benchmark the luminescence lifetime of our organic molecules (DPhCzT) with traditional

organic dyes, including classic n-π* material (benzophenone), organic light-emitting diode materials

(NPD and CBP), and typical phosphorescent metal-complexes (Ir(ppy)3 and FIrpic), we directly

compared their luminescence performance in a dark room under identical excitation conditions. Except

for DPhCzT, no noticeable luminescence was observed from traditional dyes after the 365 nm excitation

was turned off.

SV3. The DPhCzT compound in the solid state was shown as whitish needle crystals under

incandescent light. When excited with a 365 nm hand-held UV lamp (12 W), the DPhCzT sample

emitted whitish light. After the switch off of the UV lamp, an emission color change from white to

yellowish-green light was clearly observed by the naked eye. This process was repeated for three times

and the same phenomenon was observed.

SV4. This video demonstrates that when excited by a simulated sunlight with low intensity (10

mW/cm2), the compound of DPhCzT can also emit yellowish-green ultralong phosphorescence

recordable after the cease of the simulated sunlight. This material may find useful applications in

improving solar cell conversion efficiency as the long-lived excited states with enlarged migration

distance may promote the exciton dissociation probability.

XI. References

1. An, Z. F. et al. Conjugated asymmetric donor-substituted 1,3,5-triazines: new host materials for blue

phosphorescent organic light-emitting diodes. Chem-Eur. J. 17, 10871-10878 (2011).

2. Yamamoto, T. et al. π-Conjugated donor−acceptor copolymers constituted of π-excessive and π-deficient

arylene units. optical and electrochemical properties in relation to CT structure of the polymer. J. Am.

Chem. Soc. 118, 10389-10399 (1996).

3. Yu, W. L., Meng, H., Pei, J. & Huang, W. Tuning redox behavior and emissive wavelength of

conjugated polymers by p-n diblock structures. J. Am. Chem. Soc. 120, 11808-11809 (1998).

4. Förster, Th. Excimer. Angew. Chem. Int. Ed. 8, 333-343 (1969).

5. Zhao, J. Z., Wu, W. H., Su, J. F. & Gao, S. Triplet photosensitizers: from molecular design to

applications. Chem. Soc. Rev. 42, 5323-5351 (2013).

6. Uoyama, H., Goushi, K., Shizu, K., Nomura, H. & Adachi, C. Highly efficient organic light-emitting

diodes from delayed fluorescence. Nature 492, 235-238 (2012).

7. Bolton, O., Lee, K., Kim, H.-J., Lin, K. Y. & Kim, J. Nat. Chem. Activating efficient phosphorescence





43

from purely organic materials by crystal design. 3, 205-210 (2011).

8. Hirata, S. et al. Efficient persistent room temperature phosphorescence in organic amorphous materials

under ambient conditions. Adv. Funct. Mater. 23, 3386-3397 (2013).

9. Fujiwara, Y., Ozawa, R., Onuma, D., Suzuki, K., Yoza, K. & Kobayashi, K. Double alkylene-strapped

piphenylanthracene as a photostable and intense solid-state blue-emitting material. J. Org. Chem. 78,

2206-2212 (2013).

10. Zhang, C. et al. Intramolecular RET enhanced visible light-absorbing bodipy organic triplet

photosensitizers and application in photooxidation and triplet–triplet annihilation upconversion. J. Am.

Chem. Soc. 135, 10566-10578 (2013).

11. Ji, W. et al. High color purity ZnSe/ZnS core/shell quantum dot based blue light emitting diodes with an

inverted device structure. Appl. Phys. Lett. 103, 053106-053109 (2013).

12. Kawamura, Y. et al. Ultraviolet amplified spontaneous emission from thin film of 4,4’-bis(9-carbazolyl)-

2,2’-biphenyl and the derivatives. Appl. Phys. Lett. 84, 2724-2726 (2004).

13. Yuan, W. Z. et al. Crystallization-induced phosphorescence of pure organic luminogens at room

temperature. J. Phys. Chem. C 14, 6090-6099 (2010).

14. Baldo, M. A. et al. Highly efficient phosphorescent emission from organic electroluminescent devices.

Nature 395, 151-154 (1998).

15. Zhu, Y.-C. et al. Highly efficient green and blue-green phosphorescent OLEDs based on iridium

complexes with the tetraphenylimidodiphosphinate ligand. Adv. Mater. 23, 4041-4046 (2011).

16. Kobayashi, T., Ide, N., Matsusue, N. & Naito, H. Temperature dependence of photoluminescence

lifetime and quantum efficiency in neat fac-Ir(ppy)3 thin films. Jpn. J. Appl. Phys. 44, 1966-1969 (2005).

17. Endo, A. & Adachi, C. Photoluminescence characteristics of tris(2-phenylquinoline)iridium(III)

dispersed in an iridium complex host layer. Chem. Phys. Lett. 483, 224-226 (2009).

18. Endo, A. et al Measurement of phosphorescence efficiency of Ir(III) phenylphyridine derivatives in

solusion and solid-state films. Chem. Phys. Lett. 460, 155-157 (2008).

19. Kawamura, Y. et al. 100% Phosphorescence quantum efficiency of Ir(III) complexes in organic

semiconductor films. Appl. Phys. Lett. 86, 071104-071106 (2005).

20. Zuchi, G. et al. Solution, solid state, and film properties of a structurally characterized highly

luminescent molecular europium plastic material excitable with visible light. Inorg. Chem. 50, 4851-4856

(2011).

21. Nonat, A., Gateau, C., Fries, P. H. and Mazzanti, M. Lanthanide complexes of a picolinate ligand

derived from 1,4,7-triazacyclononane with potential application in magnetic resonance imaging and

time-resolved luminescence imaging. Chem. Eur. J. 12, 7133-7150 (2006).

22. Lin, Y. H., Tang, Z. L., Zhang. Z. T. & Nan, C. W. Anomalous luminescence in Sr4Al14O25:Eu, Dy

phosphors. Appl. Phys. Lett. 81, 996-998 (2002).





44

23. Xing, G. C. et al. Long-range balanced electron- and hole-transport lengths in organic-inorganic

CH3NH3PbI3. Science 342, 344-347 (2013).

24. Stranks, S. D. et al. Electron-hole diffusion lengths exceeding 1 micrometer in an organometal trihalide

perovskite absorber. Science 342, 341-344 (2013).

25. Jeon, N. J. et al. Solvent engineering for high-performance inorganic-organic hybrid perovskite solar

cells. Nat. Mater. 13, 897-903 (2014).

26. Frisch, M. J. et al. Gaussian 09, Revision A.02, Gaussian, Inc., Wallingford CT (2009).

27. Zhao, Y. & Truhlar, D. G. The M06 suite of density functionals for main group thermochemistry,

thermochemical kinetics, noncovalent interactions, excited states, and transition elements: two new

functionals and systematic testing of four M06-class functionals and 12 other functionals. Theor. Chem.

Acc. 120, 215-241 (2008).

28. Lu, T. & Chen, F. Multiwfn: A multifunctional wavefunction analyzer. J. Comput. Chem. 33, 580-592

(2012).

29. Wu, J., Liao, Y., Wu, S. X., Li, H. B. & Su, Z. M. Phenylcarbazole and phosphine oxide/sulfide hybrids

as host materials for blue phosphors: effectively tuning the charge injection property without

influencing the triplet energy. Phys. Chem. Chem. Phys. 14, 1685-1693 (2012).

30. Knupfer, M. Exciton binding energies in organic semiconductors. Appl. Phys. A 77, 623-626 (2003).

31. Zhen, C.-G. et al. Fluorene-based oligomers for highly efficient and stable organic blue-light-emitting

diodes. Adv. Mater. 21, 2423-2429 (2009).

32. Ma, J., Chen, J.Y., Idowu, M. & Nyokong, T. Generation of singlet oxygen via the composites of water-

soluble thiol-capped CdTe quantum dots-sulfonated aluminum phthalocyanines. J. Phys. Chem. B 112,

4465-4469 (2008).

32. Chen, Z., Lohr, A., Saha, M., Chantu, R. & Würthner, F. Self-assembled π-stacks of functional dyes in

solution: structral and thermodynamic features. Chem. Soc. Rev. 38, 564-584 (2009).

33. Ogi, S., Sugiyasu, K., Manna, S., Samitsu, S. & Takeuchi, M. Living supramolecular polymerization

realized through a biominetic approach. Nat. Chem. 6, 188-195 (2014).

34. Würthner, F. Supramolecular polymerization: Living it up. Nat. Chem. 6, 171-173 (2014).

35. Kasha, M., Rawls, H. R. & El-Bayoumi, M. A. The exciton model in molecular spectroscopy. Pure Appl.

Chem. 11, 371-392 (1965).

36. Birks, J. B. Excimers. Rep. Prog. Phys. 38, 903-974 (1975).

37. Eisfeld, A. & Briggs, J. S. The J- and H- bands of organic dye aggregates. Chem. Phys. 324, 376-384

(2006).

38. Saeed, A., Kazmi, M., Samra, S. A. & Flörke, U. Synthesis and crystal structure of 9-(4,6-dichloro-1,3,5-

triazin- 2-yl)-9H-carbazole. Crystal 2, 28-33 (2011).

39. Byeon, C. C. et al. Excited state lifetime and intersystem crossing rate of asymmetric pentaazadentate

45

porphyrin-like metal complexes. Appl. Phys. Lett., 84, 5174-5176 (2004).

40. Yoon, S.-J. et al. Mesomorphic organization and thermochromic luminescence of

dicyanodistyrylbenzene-based phasmidic molecular disks: uniaxially aligned hexagonal columnar liquid

crystals at room temperature with enhanced fluorescence emission and semiconductivity. Adv. Funct.

Mater. 22, 61-69 (2012).

41. Chow, P. C. Y., Albert-Seifried, S. Célinas, S. & Friend, R. H. Nanosecond intersystem crossing times in

fullerene acceptors: implications for organic photovoltaic diodes. Adv. Mater. 26, 4851-4854 (2014).

42. An, Z. F. et al. Highly efficient and stable blue-light-emitting binaphthol-fluorene copolymers: A joint

experimental and theoretical study of the main-chain chirality. J. Polym. Sci. Poly. Chem. 48, 3868-3879

(2010).





45

porphyrin-like metal complexes. Appl. Phys. Lett., 84, 5174-5176 (2004).

40. Yoon, S.-J. et al. Mesomorphic organization and thermochromic luminescence of

dicyanodistyrylbenzene-based phasmidic molecular disks: uniaxially aligned hexagonal columnar liquid

crystals at room temperature with enhanced fluorescence emission and semiconductivity. Adv. Funct.

Mater. 22, 61-69 (2012).

41. Chow, P. C. Y., Albert-Seifried, S. Célinas, S. & Friend, R. H. Nanosecond intersystem crossing times in

fullerene acceptors: implications for organic photovoltaic diodes. Adv. Mater. 26, 4851-4854 (2014).

42. An, Z. F. et al. Highly efficient and stable blue-light-emitting binaphthol-fluorene copolymers: A joint

experimental and theoretical study of the main-chain chirality. J. Polym. Sci. Poly. Chem. 48, 3868-3879

(2010).



supplementary information doi: 10.1038/nmat4259 ... · , renren deng. 2, xiaogang liu. 2,3 *, &...

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