Low-temperature and facile solution-processed two-dimensional TiS2 as an effective electron transport layer for UV-stable planar perovskite solar cells

Abstract

Charge transport layers (CTLs) play a great role in achieving highly efficient and stable perovskite solar cells (PSCs). Recently, two-dimensional (2D) materials with high mobility have been proved to be good candidates for CTLs in PSCs. Here, 2D-TiS₂ nanosheets are prepared by a simple solution exfoliation method. It is demonstrated that 2D-TiS₂ can be applied as an effective electron transport layer in planar PSCs for the first time. Using TiS₂ films prepared from solution with an optimized concentration, PSCs show a high power conversion efficiency (PCE) of 17.37%. Benefiting from the merits of solution processability, low temperature, high mobility and suitable energy level, the proposed TiS₂ fabrication method could aid the scalable production of PSCs with high efficiency and excellent UV stability. Moreover, such a facile and low-temperature film retreatment approach guarantees the application of TiS₂ as an ETL in flexible devices.