phase change material.docx

8/9/2019 phase change material.docx

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Cadmium telluride (CdTe) is a crystalline compound formed from cadmium and tellurium. It is used as an infrared optical

window and a solar cell material. It is usually sandwiched with cadmium sulfide to form a p-n junction photovoltaic solar cell.

Typically, CdTe cells use a n-i-p structure.

I

n the 19!s, "tanford #. $vshins%y of &ner'y Conversion evices first eplored the properties of chalco'enide 'lasses as a

potential memory technolo'y. In 199, Charles "ie pu*lished a dissertation, ++ at Iowa "tate /niversity that *oth descri*ed

and demonstrated the feasi*ility of a phase chan'e memory device *y inte'ratin' chalco'enide film with a diode array. 0

cinemato'raphic study in 19! esta*lished that the phase chan'e memory mechanism in chalco'enide 'lass involves

electric-field-induced crystalline filament 'rowth.+2+In the "eptem*er 19! issue of Electronics, 3ordon 4oore 5 co-founder

of Intel 5 pu*lished an article on the technolo'y. 6owever, material 7uality and power consumption issues prevented

commerciali8ation of the technolo'y. 4ore recently, interest and research have resumed as flash and #04 memory

technolo'ies are epected to encounter scalin' difficulties as chip litho'raphy shrin%s.+

The crystalline and amorphous states of chalco'enide 'lass have dramatically different electrical resistivity. The amorphous,

hi'h resistance state represents a *inary !, while the crystalline, low resistance state represents a 1. +citation needed Chalco'enide

is the same material used in re-writa*le optical media (such as C-# and :-#). In those instances, the material;s

optical properties are manipulated, rather than its electrical resistivity, as chalco'enide;s refractive inde also chan'es with

the state of the material.

0lthou'h !! "amsun' &lectronics patent application indicates


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Cadmium telluride photovoltaicsDrom i%ipedia, the free encyclopedia

0 CdTe photovoltaic array

Cadmium telluride (CdTe) photovoltaics descri*es a photovoltaic (


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3.$.2 Price &ulnera'ili ty

3.$.3 Solar tracking

$ (arket &ia'ility

o $.1 )ota'le syste!s

* See also

+ ,e-erences and notes

Further reading

edit+@ac%'round

Cross-section of a CdTe thin film solar cell.

"ince inception, the dominant solar cell technolo'y in the mar%etplace has *een *ased on wafers

of crystalline silicon. urin' the same period, the idea of developin' alternative, lower cost


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hi'h capital costs) and has not *ecome a mar%et leader. Instead, the !!.

urin' this period, two other thin films continued in development (cadmium telluride, and copper

indium diselenide or CI"-alloys). The latter is *e'innin' to *e produced in start-up volumes of 1F

! me'awatts per year *y individual companies and remains an unproven, *ut promisin' mar%et

competitor due to very hi'h, small-area cell efficiencies approachin' >!E in the la*oratory.+2

edit+6istory

!-4 CdTe


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*ein' applied to 'lass for other uses (thermally reflective windows). 4ade more conductive for of li'ht, or a*out >!E of the li'ht usa*le *y a

CdTe device. @y removin' this loss while maintainin' the other properties of the device, Chu

reached 12E efficiency in 1991, the first thin film to do so, as verified at the Jational #enewa*le

&ner'y a*oratory(J#&).+1 Chu used C"" for depositin' the CdTe. Dor his achievements in

ta%in' CdTe from its status as Kalso-ranL to a primary candidate for commerciali8ation, some thin%

of Tin' . Chu as the %ey technolo'ist in the history of CdTe development.

In the early 199!s, another set of entrants were active in CdTe commercial development, *ut with

mied results.+1 0 short-lived company, 3olden . 3olden !!!s. 0nother ineffective corporate evolution occurred at a &uropean

entrant, 0ntec. Dounded *y CdTe pioneer ieter @onnet (who made cells in the 19!s), 0ntec was

a*le to ma%e a*out E-efficient modules, *ut went *an%rupt when it started producin'

commercially durin' a short, sharp downturn in the mar%et in >!!>. !!A 0ntec

does ma%e and sell CdTe


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There has *een a lot of research on fa*ricatin' CdTe cells on flei*le su*strate since 1999. In

>!!9, &4! it switched from

amorphous silicon to CdTe as a *etter solution to the hi'her-cost crystalline silicon and announced a further 1 lines in

4alaysia. The more recently announced lines have *een operational ahead of schedule. +>2 0s of

>!!A, Dirst "olar is producin' at nearly half a 'i'awatt annual rate, +> and in >!! and >!! was

amon' the lar'est

3& announced plans to spend P!! million on a new plant and enter this mar%et +>

edit+Issues

+editCell efficiency

http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-18http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=3http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=3http://en.wikipedia.org/wiki/Harold_McMaster#Glasstechhttp://en.wikipedia.org/wiki/Harold_McMaster#Glasstechhttp://en.wikipedia.org/wiki/Harold_McMasterhttp://en.wikipedia.org/wiki/Harold_McMasterhttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-19http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-19http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-19http://en.wikipedia.org/wiki/University_of_Toledohttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-20http://en.wikipedia.org/w/index.php?title=True_North_Partners&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=True_North_Partners&action=edit&redlink=1http://en.wikipedia.org/wiki/Walton_familyhttp://en.wikipedia.org/wiki/Walton_familyhttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-rose-21http://en.wikipedia.org/wiki/John_T._Waltonhttp://en.wikipedia.org/wiki/First_Solarhttp://en.wikipedia.org/wiki/First_Solarhttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-Production-22http://en.wikipedia.org/wiki/Perrysburg,_Ohiohttp://en.wikipedia.org/wiki/Perrysburg,_Ohiohttp://en.wikipedia.org/wiki/Financial_incentives_for_photovoltaics#Germanyhttp://en.wikipedia.org/wiki/Financial_incentives_for_photovoltaics#Germanyhttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-23http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-Production-22http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-Production-22http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-24http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-Production-22http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-Production-22http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-ep2007-25http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-26http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=4http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=4http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=4http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=5http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=5http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=5http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-18http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-18http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=3http://en.wikipedia.org/wiki/Harold_McMaster#Glasstechhttp://en.wikipedia.org/wiki/Harold_McMaster#Glasstechhttp://en.wikipedia.org/wiki/Harold_McMaster#Glasstechhttp://en.wikipedia.org/wiki/Harold_McMaster#Glasstechhttp://en.wikipedia.org/wiki/Harold_McMaster#Glasstechhttp://en.wikipedia.org/wiki/Harold_McMasterhttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-19http://en.wikipedia.org/wiki/University_of_Toledohttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-20http://en.wikipedia.org/w/index.php?title=True_North_Partners&action=edit&redlink=1http://en.wikipedia.org/wiki/Walton_familyhttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-rose-21http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-rose-21http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-rose-21http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-rose-21http://en.wikipedia.org/wiki/John_T._Waltonhttp://en.wikipedia.org/wiki/First_Solarhttp://en.wikipedia.org/wiki/First_Solarhttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-Production-22http://en.wikipedia.org/wiki/Perrysburg,_Ohiohttp://en.wikipedia.org/wiki/Financial_incentives_for_photovoltaics#Germanyhttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-23http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-Production-22http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-24http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-Production-22http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-ep2007-25http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-ep2007-25http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-26http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-26http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=4http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=5


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"olar Cell &fficiencies

@est cell efficiency has plateaued at 1.2E since >!!1.+>A The opportunity to increase current has

*een almost fully eploited, *ut more difficult challen'es associated with junction 7uality, with

properties of CdTe and with contactin' have not *een as successful. 6owever, until recently the

num*er of active scientists in CdTe 9 Improved dopin' of CdTe and increased

understandin' of %ey processin' steps (e.'., cadmium chloride recrystalli8ation and contactin')

are %ey to pro'ress. "ince CdTe has the optimal *and 'ap for sin'le-junction devices, it may *e

epected that efficiencies close to eceedin' >!E (such as already shown in CI" alloys) should *e

achieva*le in practical CdTe cells. 4odules of 12E would then *e possi*le.

+editProcess optimization

! year) 'oal for CdTe modules resultin' from com*inin' cost and

efficiency 'oals would *e P2 per 12! watts, or a*out P!.2 per watt. +1 ith commodity-li%e

mar'ins and com*ined with *alance-of-system (@$") costs, installed systems near P1.2G seem

achieva*le. ith "outhern California sunli'ht, this would *e in the to A /" cents per %h ran'e

(e.'., *ased on economic and other assumptions used in al'orithms such as in the /nited "tates

epartment of &ner'y and J#&;s "olar 0dvisory 4odel).+>

+editTellurium supply


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a*undant element in the universe with an atomic num*er over !.++A This surpasses, e.'.,

heavier materials li%e tin, *ismuth, and lead, which are common. #esearchers have shown that

well-%nown undersea rid'es (which are now *ein' evaluated for their economic recovera*ility) are

rich in tellurium and *y themselves could supply more tellurium than we could ever use for all of

our 'lo*al ener'y.+A+9 It is not yet %nown whether this undersea tellurium is recovera*le, nor

whether there is much more tellurium elsewhere that can *e recovered.

+editOther issues

[ edit ] Cadmium

0nother issue fre7uently mentioned, is the use and recyclin' of the etremely toic

metal cadmium, one of the si most toic materials *anned *y &uropean /nion;s #o6"re'ulation.

0ccordin' to Dirst "olar;s annual report,+!

the CdTe solar panel is not in #o6" compliance, not

listed in the eemption product list, *ut not currently listed in the restricted product list either. "o

the product;s future #o6" compliance status is uncertain.+1 Dirst "olar has a self-imposed

recyclin' re'imen that provides a deposited amount (RP!.!2 a watt) that covers the costs of

transport and recyclin' of the module at the end of its useful life.+>+ #ecyclin' has *een fully

demonstrated on scrap modules althou'h recent wor% has 7uestioned the economic via*ility of

recyclin' CdTe


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dependent. Trac%in' also produces a smoother output plateau around midday, allowin' afternoon

pea%s to *e met.

edit+4ar%et via*ility

"uccess of cadmium telluride irect manufacturin' cost for CdTe !1!, + and capital

cost per new watt of capacity is near P!.9 per watt (includin' land and *uildin's). +A 6owever,

module cost alone is not enou'h to assure the lowest installed system price. Thin films, includin'

CdTe, are less efficient than most wafer silicon modules. Typical wafer silicon modules are 1E to

>!E efficient, while the *est CdTe modules were a*out 1!.E efficient recent modules produced

at Dirst "olar and measured *y J#& have shown CdTe modules with efficiencies at 1>.2E or

'reater. 4any components of an installed 2! me'awatts at a total cost of PA24

(avera'in' P.2Gwatt), after incentives.+21

http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=12http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=12http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=12http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-ep2007-25http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-46http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-46http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-ep2007-25http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-47http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=13http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=13http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=13http://en.wikipedia.org/wiki/First_Solarhttp://en.wikipedia.org/wiki/First_Solarhttp://en.wikipedia.org/w/index.php?title=Juwi_group&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Juwi_group&action=edit&redlink=1http://en.wikipedia.org/wiki/Waldpolenz_Solar_Parkhttp://en.wikipedia.org/wiki/Waldpolenz_Solar_Parkhttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-48http://en.wikipedia.org/wiki/California_Public_Utilities_Commissionhttp://en.wikipedia.org/wiki/California_Public_Utilities_Commissionhttp://en.wikipedia.org/wiki/California_Public_Utilities_Commissionhttp://en.wikipedia.org/wiki/Power_purchase_agreementhttp://en.wikipedia.org/wiki/First_Solarhttp://en.wikipedia.org/wiki/First_Solarhttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-49http://en.wikipedia.org/wiki/Dispatchable_generationhttp://en.wikipedia.org/wiki/Dispatchable_generationhttp://en.wikipedia.org/wiki/Southern_California_Edisonhttp://en.wikipedia.org/wiki/Southern_California_Edisonhttp://en.wikipedia.org/wiki/Southern_California_Edisonhttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-50http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-50http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=12http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-ep2007-25http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-ep2007-25http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-ep2007-25http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-ep2007-25http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-46http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-47http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=13http://en.wikipedia.org/wiki/First_Solarhttp://en.wikipedia.org/w/index.php?title=Juwi_group&action=edit&redlink=1http://en.wikipedia.org/wiki/Waldpolenz_Solar_Parkhttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-48http://en.wikipedia.org/wiki/California_Public_Utilities_Commissionhttp://en.wikipedia.org/wiki/California_Public_Utilities_Commissionhttp://en.wikipedia.org/wiki/Power_purchase_agreementhttp://en.wikipedia.org/wiki/First_Solarhttp://en.wikipedia.org/wiki/First_Solarhttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-49http://en.wikipedia.org/wiki/Dispatchable_generationhttp://en.wikipedia.org/wiki/Southern_California_Edisonhttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-50


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Cell efficiency

"olar Cell &fficiencies

@est cell efficiency has plateaued at 1.2E since >!!1. +>A The opportunity to increase current has *een almost fully

eploited, *ut more difficult challen'es associated with junction 7uality, with properties of CdTe and with contactin' have not

*een as successful. 6owever, until recently the num*er of active scientists in CdTe 9 Improved dopin' of

CdTe and increased understandin' of %ey processin' steps (e.'., cadmium chloride recrystalli8ation and contactin') are %eyto pro'ress. "ince CdTe has the optimal *and 'ap for sin'le-junction devices, it may *e epected that efficiencies close to

eceedin' >!E (such as already shown in CI" alloys) should *e achieva*le in practical CdTe cells. 4odules of 12E would

then *e possi*le.

+editProcess optimization

! year) 'oal for CdTe modules resultin' from com*inin' cost and efficiency 'oals would *eP2 per 12! watts, or a*out P!.2 per watt. +1 ith commodity-li%e mar'ins and com*ined with *alance-of-system (@$")

costs, installed systems near P1.2G seem achieva*le. ith "outhern California sunli'ht, this would *e in the to A /"

cents per %h ran'e (e.'., *ased on economic and other assumptions used in al'orithms such as in the /nited "tates

epartment of &ner'y and J#&;s "olar 0dvisory 4odel).+>

http://en.wikipedia.org/wiki/Solar_cell#Solar_cell_efficiency_factorshttp://en.wikipedia.org/wiki/Solar_cell#Solar_cell_efficiency_factorshttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-27http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-27http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-28http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-28http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=6http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=6http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=6http://en.wikipedia.org/wiki/Substrate_(materials_science)http://en.wikipedia.org/wiki/Substrate_(materials_science)http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-29http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-30http://en.wikipedia.org/wiki/United_States_Department_of_Energyhttp://en.wikipedia.org/wiki/United_States_Department_of_Energyhttp://en.wikipedia.org/wiki/United_States_Department_of_Energyhttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-solaradvmodel-31http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-solaradvmodel-31http://en.wikipedia.org/wiki/United_States_Department_of_Energyhttp://en.wikipedia.org/wiki/Solar_cell#Solar_cell_efficiency_factorshttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-27http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-28http://en.wikipedia.org/w/index.php?title=Cadmium_telluride_photovoltaics&action=edit&section=6http://en.wikipedia.org/wiki/Substrate_(materials_science)http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-29http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-30http://en.wikipedia.org/wiki/United_States_Department_of_Energyhttp://en.wikipedia.org/wiki/United_States_Department_of_Energyhttp://en.wikipedia.org/wiki/United_States_Department_of_Energyhttp://en.wikipedia.org/wiki/United_States_Department_of_Energyhttp://en.wikipedia.org/wiki/United_States_Department_of_Energyhttp://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-solaradvmodel-31http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics#cite_note-solaradvmodel-31


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phase change material.docx

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