NOVEL CDTE/SILICON SOLAR CELLS USING TRIPLE ABSORBER

The efficiencies of thin film solar cells are low compared to crystalline Silicon (Si) solar cells, however, they are cheap and easy to manufacture. As the enhancement in efficiency of Cadmium Telluride (CdTe) solar cell becomes more and more difficult, it is very necessary to involve advanced structure or new materials. In this paper, a novel CdTe/Silicon solar cells using triple absorber is proposed and investigated. The proposed solar cell structure consist of ITO/ZnO/CdS/CdTe/n-Si/p-Si/CZTS/Al layers, where CdTe, silicon and Copper Zinc Tin Sulfide (CZTS) are used as absorber layers, Cadmium Sulphide (CdS) as buffer layer, Indium Tin Oxide (ITO) and Zinc Oxide (ZnO) as window layer, and Aluminum (Al) as back contact. The proposed structure shows the advantages of relatively high open circuit voltage and large short circuit current. It should be mainly photons with short wavelength range can be absorbed by CdTe and CZTS layers while long wavelength range can be absorbed by Si layer. In this way, the proposed structure with an ۵۰ nm thick Si layer and the ۲۰۰ nm thick CdTe and CZTS absorber layers, an efficiency of ۳۳.۱۵% is predicted using calibrated simulations. Finally, the highest theoretical conversion efficiency of ۳۸.۷۱% was obtained by carrier lifetime variation in the absorber layers of proposed solar cell.