NO2-induced performance enhancement of PEDOT:PSS/Si hybrid solar cells with a high efficiency of 13.44.

Using poly (3,4-ethylene-dioxythiophene): poly(styrenesulfonate) ( PEDOT: PSS) as an effective hole collecting layer, high-efficiency PEDOT: PSS/n-Si hybrid solar cells are fabricated and a power conversion efficiency (PCE) of 12.13% is obtained. After being treated by HNO3 vapor, the PCE value of PEDOT: PSS/n-Si hybrid solar cells enhances from 12.13% to 13.44%. NO2 gas molecules in HNO3 vapor play a significant doping role in raising the PCE of solar cells. As the doping level raises, NO2 would get more electrons from PEDOT and lead to the increase of hole carriers in the films, which improves the polymer film's conductivity and PCE of solar cells.