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A solar cell is any device that directly convertsthe energy in light into electrical energythrough the process of photovoltaics.

First Generation Solar CellsCrystalline Silicon Cells

Second Generation Solar CellsAmorphous Si, GaAs, CdTe, CIS, CIGS

Third Generation Solar CellsDye-sensitized cells,


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Relatively cheap inproduction and

purification

Materials can betailored for the

demand

Can be used on

flexible substrate

Can be shaped or

tinted to suitarchitecturalapplications


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Do not reach the energyconversion efficiencyexceeding 24 % innorganic materials.

Limited lifetime/ stability


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Recently hybrid solar cell (HSC) which is thecombination of inorganic and organicmaterials are widely studied and theefficiency of the device has reached above

5%.

Polymers are the common donors

whereas nanoparticles act ascommon acceptors.


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nanoparticles

polymer


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Highest efficiency was recorded in therandom mixtures of conjugated polymers andinorganic nanoparticles.

Provide continuouspathways for chargetransport in the

through-filmdirection.

Maintainsolution

processability.

Have thepotential forfurtherenhancement of

electrontransport.


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Mesoporous inorganic films infused with

electron-donating organic structures, Alternating inorganic-organic lamellar

structures,

And

Nanoscale structures;


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Different inorganic nanowires such GaAs, Si, TiO2,CdS, ZnO and Ag were used in the literature.

Use of nanowire instead of PCBM as an acceptor

group

Use of nanowire as an additional group


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A blend of poly(3-hexylthiophene) (P3HT) and narrowbandgap GaAs Nanowires is used.

Coating the GaAs nanowireswith TiOx shells passivates

nanowire surface states andfurther improves thephotovoltaic performance.

Power conversion efficiencieswere reported as 2.36%.

Device architecture

Nano Lett. 2011, 11, 408

413


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Absorption spectra of a P3HT thin film, GaAsnanowires , GaAs20%, and GaAs50% blends.


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Comparison of EQE data for P3HT hybrid cells withdifferent NW loading.


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Well-alignedsingle-crystalline Si nanowires (SiNWs)and poly(3 hexylthiophene):[6,6]-phenyl-C61-butyricacidmethylester (P3HT:PCBM) were used asan active layer.

Provide uninterrupted conduction paths for

electron transport. Enhance the optical absorption.

Increase the surface area for exciton dissociation.

Solar Energy Materials & Solar Cells 93

(2009) 621624


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(a)A schematic of the

hybrid solar cellusing SiNWs andP3HT:PCBM blend

(b)The setup for

transferring theSiNWs onto theP3HT:PCBM blend

(c) A schematic of themachine with lateralforce used toseparate the siliconwafer from theP3HT:PCBM blend.


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Jsc increases from 7.17 to 11.61 mA/cm2and PCE increases from 1.21% to 1.91%.

Si nanowires can be fabricated at lowtemperature from solution processing withoutany vacuum equipment or high-temperatureprocessing


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The current densityvoltage characteristics for the solarcells with and without the SiNWs .


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Hybrid Solar Cells have some certain advantages because they

combine the unique properties of the inorganicsemiconductor nanoparticle with those of the polymericmaterials

Combination of the NWs and P3HT:PCBM blend is anattractive route to obtain high Jsc and efficiencies by

improving the optical absorption

increasing the dissociation of excitons

improving the electron transport


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