Effect of Cu and Sn concentration on the performance of all-sprayed CZTS solar cell

Abstract

Cu2ZnSnS4/In2S3 thin film solar cell was prepared using chemical spray pyrolysis. Influence of variation in copper concentration in precursor solution on the properties of CZTS thin films was monitored. Concentration of copper was found to have essential role in adjusting composition and crystallinity of CZTS thin films. Junction was fabricated using CZTS as absorber layer and spray pyrolysed In2S3 as buffer layer. Two sets of devices were prepared, one by varying copper concentration and the other by varying tin concentration in the precursor solution for the deposition of CZTS thin films. For both sets, In2S3 thin films were deposited as buffer layer and Ag electrodes were used for taking contacts. All the performance parameters were found to have dependence on the concentration of Cu and Sn. For getting maximum conversion efficiency, the sprayed CZTS absorber layer should have elemental ratio of Cu:Zn:Sn:S=2.5:1:0.7:12 in the precursor solution. Maximum efficiency obtained was 1.85 %.