TF Silicon Status and OutlookBeyond the metric EfficiencyEdward Hamers (HyET Solar), Arno Smets (TU Delft)

22-6-2017 Final

Glass based PV in urban environment

2

➢ Utilization of available area is limiting factor

Imagine a PV product ….

✓ Lightweight✓ Flexible✓ Custom-sizing✓ Easy to integrate✓ Low cost

➢ Optimal area coverage

Unique technology enables a unique product

Flexible in shape and size

Light-weight (600 gr/m²)

Ultra flexible

✓ Reinforcement of roof structures not necessary

✓ Dimensions of covered objects do not change

✓ Creation of aesthetic and low cost building solutions

✓ Module characteristics do not restrict architectural creativity

4

Ultra thin (0.5 mm)

5

Pr1: Front contact Pr2: Silicon Pr3: Interconnection Pr4:BackContact

Pr5: Lamination Pr6: Etching Pr7: Encapsulation Pr7: Quality Control

HyET Solar Foil: Production equipment

Production scale Production scale Production scale

Pilot scale Production scale Production scalePilot scale

Pilot scale

➢ Pilot scale: 350 mm, 1-10 MWp/yr ; Production scale:1400 mm width, 25-50 MWp/yrTRL typically 6-7

Unique selling points of TF-Si

•Roll-to-roll manufacturing

•Low material costLowest cost

•Abundant materials used

•Compatible with regulations

•Moisture resistant TCO SnO2 and absorber layer

Abundant materials

•Shadowing of part of module is in general not dramatic for performance Shadowing

•More sensitive to larger angles as light in coupling improves

•Low light performance is goodDiffuse light

•Temperature coefficient is relatively low Temperature

Dif

fere

nce

ST

C a

nd

RO

C

Product reliability

7

✓ Product passes IEC

Meaning a.o.– Accelerated Lifetime testing

– Hailstones

– Cut susceptibility

– Fire testing

– Own outdoor monitoring

Robust and reliable product, eg.

Cut Susceptibility

• Safety aspect

Unencapsulated Damp Heat

• Hot Moisture resistant to >>1000h

Lowest cost PV product: module level

9

➢ Cost more important than efficiency [consumer perspective]➢ Manufacturing scale important influence on module cost➢ Balance of System costs are ca. 50% of PV system

10-3

10-2

10-1

100

101

102

103

1

10

100

Q4-2016

1995

1985

1975 PVm

odule

Q4-2015

Q1-2011

Q1-2009

Module

price

Inflation a

dju

ste

d €

2015/W

p

Cumulative Production (GWp)

Q2-2006

PV System

Source: Fraunhofer ISE Navigant Consulting

0,00

0,50

1,00

1,50

2,00

2,50

B6.4: 7% B6.4T:10%

B7.0: 8% B7.0T:11%

Mat

+Lab

or

(Eu

ro/W

p)

Scenario

Effect of both scale up and Efficiency

Materials+Labor

Materials

Labor

1 MWp/yr

25 MWp/yr

Production cost PV module HyET Solar

Lowest cost PV product: system level/BoS costs

Flexible in shape and size

Light-weight (600 gr/m²)

Ultra flexible

✓ Reinforcement of roof structures not necessary

✓ Dimensions of covered objects do not change

✓ Module characteristics do not restrict architectural creativity

10

Ultra thin (0.5 mm)

Large modules (>10 m2) reduces Cabling in BoS

Integration saves on Installation BoS

Low weight saves on installation BoS and Light-weight and low volume saves on transport in BoS

✓ Creation of aesthetic and low cost building solutions

Lowest cost PV product: system level/BoS costsBAPV: applied on the roof BIPV: applied in the factory

BoS costs: Mechanical installation0.20 €/Wp (7%) same as c-Si 16%

BoS costs: Mechanical installation<0.05 € /Wp (@ 7%)

➢ Reduction of about 30% on total BoS costs wrt conventional c-Si modules

➢ Flexible product makes huge savings already at low efficiency

Lowest cost PV product: system level/BoS costs

24 m long monolithically

integrated module: 470 Wp

Design: 2 x 10 m long modules on

roofing membrane in

series: 610 Wp

➢ Very large area >1 kWp modules possible ➢ Applications: airport terminals, large industrial buildings, land fills

Energy production compared

22-6-2017 Final

LCOE compared: power plant 8%

22-6-2017 Final

Efficiency Roadmap

Future technology generations (Si & Roll to Roll based) to guarantee continued leadership

Now: €/Wp

➢ Single junction amorphous Si: approx. 8% 0.43

➢ Tandem junction amorphous / microcrystalline Si: approx. 11 % 0.35

Future:

➢ (2017) Tandem junction amorphous/microcrystalline Si (current processes): 11% - 12% 0.32

➢ (2018) Tandem junction amorphous/microcrystalline (NG – SiH4/SiF4): 13 + % 0.31

➢ (2019) Triple junction amorphous/microcrystalline / TF c-Si: 15 + % 0.28

➢ (2019) Triple junction amorphous/microcrystalline / SiGe: 18 - 20% 0.22

➢ (2020) Tandem junction microcrystalline/perovskite: 15 + %

Note: all largely possible to manufacture with existing factory equipment

15

Product Co-Development along the value chain

Pilot Production& Manufacturing through own

and licencees & marketing

Co Development Partners

Front End

Joint Venture Partner

Back End

Innovation Multiplier by involving partners in

the development, manufacturing, sales and

marketing of final products

Equipment suppliers

Material suppliers

Know-how partners Installer

?Clients

Installer

?

Installer

?FundingLocal KnowledgeLarge Scale ManufacturingManufacturing development

marketing

Large area markets with medium gross margin • Roofing Membranes

– Homes

– Large buildings

• Corrugated plates

– Farms

– Developing countries

• Landfills:

– Covering Landfills

• Truck manufacturers

– Spoilers

– Trailers

Bring the sun to the built environment

HOW TO FURTHER REDUCE LCOE: INCREASE EFFICIENCY

22-6-2017 Final

Record single junction TF Si solar cell [AcAS]

• after 1000 h light soaking• subsequently attached anti reflection foil• solar cell area definition by laser scribing➢ Different groups achieved similar efficiencies

0.0 0.2 0.4 0.6 0.8

-15

-10

-5

0

= 10.26%

FF = 67.0%

Voc

= 0.891 V

Jsc

= 17.2 mA/cm²

A = 1 cm²

cu

rre

nt

de

nsity J

[m

Acm

-2]

voltage V [V]

A. Lambertz et al. (submitted 2015)

0.0 0.3 0.6 0.9 1.2 1.50

2

4

6

8

10

12

14

16

Cu

rrent D

ensity (

mA

/cm

2)

Voltage (V)

Voc=1.424 V

Jsc =14.0 mA/cm2

FF =74.4%

Eff =14.8%

a-Si:H

nc-Si:H

H. Tan et al. PiP 23, 949(2015)

Record tandem junction TF Si solar cell

Stabilized 12.5%

➢ Several groups reached stabilized efficiencies of 12.3-12.7% on cell level

Cell TU Delft Module 1.43 m2 TEL Solar

• Stabilized 12.34%

This work was accepted 1st June 2015 for publishing in Progress in Photovoltaics: Research and Applications:

“Record 12.34% stabilized conversion efficiency in a large area thin-film silicon tandem (MICROMORPH™) module”

21

14.04%

H. Sai et al. APL 183506 (2016)

Record triple junction TF Si [AcAS]

22

Hybrid PV Structures

T3

T4

T1

T2

Mildly textured front TCO

AZO

Ag/MoO3

PMDPP3T:PC6

0BM

LiF/Al/Ag

a-Si:H p-i-n front

a-Si:H p-i-n middle

glass

2,3,4-j: c-Si/ TF Si Hybrids for high voltage

1j a-Si/c-Sihetero-junction

2j 4-terminal (4T)/4T - spectral splittinga-SiOx:H/c-Si

2j a-Si:H/nc-Si:H4j a-SiO:H/a-Si:H/

nc-Si:H/nc-Si:H

3j a-Si:H/a-Si:H/OPV

2j a-Si:H/CIGS

2,3,4-j: c-Si/ TF Si for solar-to-fuel:

Efficiency Roadmap

Future technology generations (Si & Roll to Roll based) to guarantee continued leadership

Now:

➢ Single junction amorphous Si: approx. 8%

➢ Tandem junction amorphous / microcrystalline Si: approx. 11 %

Future:

➢ (2017) Tandem junction amorphous/microcrystalline Si (current processes): 11% - 12%

➢ (2018) Tandem junction amorphous/microcrystalline (NG – SiH4/SiF4): 13 + %

➢ (2019) Triple junction amorphous/microcrystalline / TF c-Si: 15 + %

➢ (2019) Triple junction amorphous/microcrystalline / SiGe: 18 - 20%

➢ (2020) Tandem junction microcrystalline/perovskite: 15 + %

Note: all largely possible to manufacture with existing factory equipment

23

Status & Roadmap TF SiFlexible TF Si PV modules: next standard in PV production

Next steps: ➢ Secure financing for scale up to 25 MWp/yr in Arnhem and ➢ Develop market for 3-4 international 200 MWp/yr fabs in licence production.

Roadmap• Supply chain raw materials cost reduction especially encapsulation• Towards production tools for GWp/yr production• Towards building element lifetimes 25 yr+• Develop products for large niche applications : GWp scale• Demonstration projects and educate market on possibilities • Educate installers• Further cost reduction: efficiency improvement

22-6-2017 Final

The effect of module temperature

Output in terms of Power

0

50

100

150

200

250

0 20 40 60 80 100 120

P (

Wp

/m2

)

Temperature (°C)

Effect module temperature

P_cSi

P_aSimucSi

P_aSi

Relative wrt STC

60%

70%

80%

90%

100%

110%

120%

0 20 40 60 80 100 120

Rel

ativ

e P

ow

er w

rt S

TC

Temperature (°C)

Effect module temperature

Prel_aSi

Prel_aSimucSi

Prel_cSi

Γrel (%/K)

c-Si -0.45

a-Si:H -0.13

a-Si:H/muc-Si:H -0.33

STC

Technology:Temporary Aluminium ‘superstrate’

Use of substrate Aluminium foil essential

Step 1 : TCO (SnO2:F) at 500°C

Step 2 : a-Si:H & nc-Si:H at 200°C

Step 3 : Back contact

Step 4 : Interconnection

Step 5 : Carrier lamination

Step 6 : Removal Al foil

Step 7 : Encapsulation & Quality Control

➢ Unique high temperature process via Aluminium foil yields an energy efficient, very thin and extremely flexible product

➢ This production advantage eliminates traditional thin film silicon concerns

26

Energy yields as you know it

Same energy yield as others– Green: HyET Solar 103 W

– Blue: c-Si Solarfun 175 W

– Brown: Unisolar 136 W

0

50

100

150

februari maart april mei juni juli aug sept okt nov dec

Yie

ld (

kW

h/k

Wp

per

maan

d)

Helianthos 2 * 53 Wp Helianthos 2 * 103 Wp (1) Helianthos 2 * 103 Wp (2)

Helianthos 2 * 103 Wp (3) Helianthos 2 * 103 Wp (4) c- Silicium referentie (Solarfun 175 Wp)

a-Si triple junction referentie (Unisolar 136 Wp)1 year comparison outdoor data

Improved IR absorption in nc-Si:H from SiF4Increase bottom cell crystallinity with SiF4 precursor

Q. Zhang, PSS-RRL 2008S. Hänni, Ph.D. Thesis EPFL 2014

32 mA/cm2

➢ > 15 mA/cm2 matched, ➢ Potential (assuming 71% FF and 1.4 V): η ≈ 15%

EPFL PV-Lab

Unique technology advantages

29

• High quality due to processing T of 500°C

• Moisture resistant and thus durable SnO2:FGood and durable TCO

• Abundant materials are used

• Silicon does not require a low WVTR

Abundant and stable materials

• Monolithic interconnection dead zone <300 micron

• Only one process step

Monolithic interconnection

• Transport and process combined saves Capex

• Stable processing at high level of automation

Continuous R2R processing

• Glass know-how to improve performance

• Strong know-how basis

Device build-up just as on glass

Excellent Lifetime stabilityDamp Heat (85ºC, 85% RH) Stability

a-Si:H and a-Si:H/µc-Si:H

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

0 500 1000 1500 2000 2500 3000 3500 4000 4500

Testing Time (h)

Eff

icie

nc

y (

%)

roll-to-roll a-Si:H 28x30 cm² modules

batch tandem 5x5 cm² modules

IEC norm

testing time

➢ Lifetime is combination of PV layer technology used and the encapsulation system

Status PV technologies: upscaling to production

Courtesy: Arno Smets

➢ Thin Film silicon seems to be the technology that is scaled up the easiest

0.1 1 10 100 1000 100000

4

8

12

16

20

24

28

32

36

40

1j-organic PV

(not stabilized)

1j-perovskite (not stabilized)

3j-InGaP/GaAs/InGaAs

MODULE

WAFER

1j-FZ c-Si: HIT

2j-TF Si

3j-TF Si

1j-CdTe

1j-CIGS

1j-mc-Si

Eff

icie

ncy (

%)

Area (cm2)

1j-FZ c-Si: IBC

LAB CELL

1j-GaAs

10 m2 100 m2

roll-to-roll

Batch

24

m lo

ng,

7 m

2m

od

ule

TF-Si community: R&D activities on efficiency

• Anti-reflection concepts

• Light trapping conceptsAntireflection

• Different TCO’s

• Different surface morphologiesTCO

• Doped SiOx layers to reduce absorptionSingle cell

• Intermediate reflector layers

• SiF4 as precursor in nc-Si:H depositionTandem cell

• Alloys Si-Ge

• Applications for water splittingTriple cell

• Use of n-SiOx doped layer in Back reflectorBack Reflector

Tandem at HyET Solar

Device lay-out Performance

• 5 cm2 cell in module configuration

Voc(V)

FF(-)

JsrToC(mA/cm2)

JsrBoC(mA/cm2)

Eff(%)

Initial 5 cm2 1.325 0.740 11.75 11.10 10.9

20 nm

i-pm-Si:H 300 nm

ZnO:Al 70 nm

SnO2:F

p-a-Si:C:H

Ag 120 nm

n-a-Si:Hn-SiOx:H 60 nm

n- a- Si:H

i-nc-Si:H 1600 nm

a-Si

µ-Si

p-SiOx:H

AR

Native Texture

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

300 400 500 600 700 800 900 1000 1100

EQE

(-)

Wavelength (nm)

Light-Induced Water-Splitting using anIntegrated Photoelectrochemical Thin-Film Si Device

Urbain et al., Sol. Energy Mater. Sol. Cells 140 (2015) 275Urbain et al., J. Mater. Res. 29 (2014) 2605Ziegler et al., ChemPhysChem 15 (2014) 4026

Solar-To-Hydrogen Efficiency:

ηSTH = 9.5%

PV Efficiency and Stability Integrated water-splitting device

▪ Multijunction Si thin-film solar cells for water-splitting: Voc up to 2.8 V

▪ Stabilized solar cell efficiency of ηPV = 12.5%

▪ Solar-to-hydrogen efficiency ηSTH = 9.5%

ηPV = 12.5%

How important is efficiency

1. Allows comparison very similar products

2. With similar materials it will lower $/Wp

3. With similar production technology it will lower $/Wp

4. With similar BoS costs it will lower $/Wpsystem costs

➢Efficiency is a very important driver

Is something else also important ?Glass 20% (per m2)

Glass 10%(per m2)

Flexible 10% (per m2)

Unique Selling Points

Arguments #1 Arguments #2 Arguments #3

Key numbers per m2

200 Wp; 10 kg; $100

100 Wp; 10 kg;

$50

100 Wp; 0.5 kg;

$50

PowerDensity 200 Wp/m2 100 Wp/m2 100 Wp/m2

PowerDensity 20 Wp/kg 10 Wp/kg 200 Wp/kg

Mass per MWp 50 tonnes/MWp 100 tonnes/MWp 5 tonnes/MWp

Price per kg $ 10/kg $ 5/kg $ 100/kg

Price per m2 $ 100/m2 $ 50/m2 $ 50/m2

➢Mass does also matter as well as area

Increasing production width to 1400 mm

Step 1: TCO

• Roll-to-roll

Step 2: Silicon

• Stationary

38

✓ Thickness 300±2 nm

from 2 cm from edge

Pr1: FrontContact

Pr2: Silicon

Pr3: Interconnection

Pr4: BackContact

Pr5: Lamination

Pr6: Etching

Pr7: Encapsulation

Pr8: Confectioning

Auxiliary Processes

22-6-2017 Final

80 m

150 m

39

Factory lay-out 200 MWp/yr

Avoiding defects by avoiding sharp features in TCO

LPCVD ZnO:B Z2.3 4’Ar Modulated textures

Liquid-Phase Crystallized Silicon on Glass

-0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7-30

-25

-20

-15

-10

-5

0

5

Curr

ent

densi

ty (

mA

/cm

²)

Voltage (V)

1-49-140-133, cell 3

superstrate

Jsc = 27.25 mA/cm²

Voc = 649 mV

FF = 68.4 %

ETA = 12.1 %

• 20/100/80 nm SiN/SiO/SiON• 5-10 µm LPC-Si n-type absorber,• i/p hetero emitter, back-side contact scheme• white reflector + textured AR foil.

O. Gabriel et al., IEEE J-PV 2014

IL stack

5 µm - 40 µm Si precursor layer

glassLPC-Si

e-beam / cw laser

J. Haschke et al., Sol.Mat 2014

D. Amkreutz et al., Prog. PV Res. Appl. 19, 937 (2011)

interlayer

a-Si:H(i/p)

insulatorITO

Ti/Pd/Ag contacts

T. Frijnts et al., submitted