Enhancing Performance of PSCs Using Nb-Doped SnO_2 Nanosheets as Electron Selective Layers

【摘要】：The excellent electron transport layer can improve the performance of PSCs. In this paper, the niobium-doped tin oxide(Nb-Sn O2) nanosheets were synthesized by solvothermal method and used as ETL in PSCs. Characterization through TEM and SEM tests shows that the Nb-SnO_2 nanosheets are uniformly distributed, which facilitates better contact between the perovskite layer and the electron transport layer and improves the electron mobility from the perovskite layer to the ETL interface. Due to the doping effect of Nb ions, the bandgap and highband energy levels are amplified, resulting in better energy levels aligned with the perovskite, and reduced electronic recombination. The experimental results show that the PSCs based on the Nb-SnO_2 nanosheets ETL have better performance than the SnO_2-NRs ETL-based PSCs, the hysteresis is significantly reduced,and then the PCE of the PSCs is increased. Nb-SnO_2 ETL-based PSCs achieved a photovoltaic conversion efficiency of 19.68%(19.13%) and a steady state efficiency of 19.38% when measured in reverse(forward) voltage scans.