Improved performance in Ag2S/P3HT hybrid solar cells with a solution processed SnO2 electron transport layer

Abstract

We successfully constructed a heterojunction structure composed of Ag₂S nanocrystals/P3HT conjugated polymer with a relatively high absorption coefficient and broader absorption from the ultraviolet to near-infrared region. The assembled P3HT:Ag₂S devices exhibited outstanding short-circuit current density around 19 mA cm⁻². Meanwhile, we demonstrated that a low-temperature solution-processed nanocrystalline SnO₂ thin film prepared by a facile synthesis method can be an excellent electron transport layer (ETL) material for hybrid solar cells. The SnO₂ based hybrid solar cells exhibit an open circuit voltage of 280 mV, which was 100 mV higher than those for devices without SnO₂. Based on the above work, we hypothesized that the higher power conversion efficiency is due to the excellent properties of nanocrystalline SnO₂ films, such as high electron mobility and excellent transparency at visible wavelength and enhanced exciton dissociation efficiency, and better energy level alignment between FTO and Ag₂S for greater photovoltage retention. The simple low temperature low energy consumption, and low-cost soft-chemical process is compatible with the roll-to-roll manufacturing of low-cost hybrid solar cells on flexible substrates.