A numerical analysis on CdS:O window layer for higher efficiency CdTe solar cells

Polycrystalline thin film CdTe solar cell continues to be a leading candidate in the PV research and market because of its cost effectiveness and efficiency. In the conventional CdTe cell, polycrystalline cadmium sulfide (CdS) has been used as the best suited n-type heterojunction partner in the last few decades. This study demonstrates the use of novel CdS:O film as n-type heterojunction partner of CdTe cell, which has higher optical band gap (2.42-3.1eV), better lattice-match with CdTe and reduces the unwanted diffused layers than the poly-CdS layer. This novel CdS:O material is utilized in the baseline case of CdTe cell and a cell conversion efficiency as high as 18.5% (J_sc =26.56 mA/cm², Voc = 0.95 V and FF=0.8) has been found by numerical analysis utilizing AMPS-1D software. The cell normalized efficiency and Voc are found to decrease linearly at the operating temperature gradient of -0.2%/??C, indicating higher stability of the material at higher operating temperatures.