Effects of different interface on the stability of hybrid heterojunction solar cells

With the rapid increase in efficiency of organic-inorganic hybrid solar cells of Si-poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), their poor stability has become an important factor limiting its further development. Here, we demonstrate that the moisture in the air is the main cause for the performance degradation of the hybrid heterojunction solar cells (HHSCs) and innovatively discovered the effect of the Ag electrodes on the degradation of HHSCs. When exposed to air, the growth of the thin oxide layer on the interface of n-Si/PEDOT:PSS and the formation of silver sulfide (Ag2S) on the Ag/PEDOT:PSS interface together caused the increase in the series resistance (Rs) of the HHSCs. The increase in Rs decreases the fill factor (FF) of the HHSCs and thus leads to the degradation of the cell performance.