Interface modification of SnO<inf>2</inf> layer using P–N junction double layer for efficiency enhancement of perovskite solar cell

Abstract

© 2020 IOP Publishing Ltd. In this work, interface modification of SnO2 layer using p–n junction double layer is investigated for the efficiency enhancement of perovskite solar cell (PSC). For the double layer, a Sn additive layer was applied on a SnO2 layer by using the DC magnetron sputtering technique at various deposition times. The highest power conversion efficiency of 15.11% is obtained for PSC with a SnOx additive layer at 5 s sputtering time, compared to 12.89% for the best PSC without the additive layer. The effect of the SnOx additive layer on PSCs at optimum sputtering time is further explored via the photoconversion properties of both optical and electrical properties. From the results, it is found that the SnOx additive layer is essential for efficiency enhancement by forming the p-n junction with a SnO2 electron transporting layer (ETL) and modifying the interface between the ETL and the perovskite layer. The p-n junction of the ETL is observed via the diode-like behavior of I–V characteristics. The interface modification can enhance the PSC efficiency by improving the quality of the perovskite layer due to the larger grain size and higher absorbance, and by improving the charge transfer. The faster photogenerated charge transfer is confirmed by lower PL intensity and the shorter charge transfer lifetime is confirmed by the fitted open-circuit voltage decay. In addition, the SnOx additive layer can also eliminate the hysteresis effect of PSCs. This interface modification technique for PSC efficiency enhancement could be further explored for other ETLs.