Low-temperature processed In2S3 electron transport layer for efficient hybrid perovskite solar cells

Abstract

As a new generation of photovoltaics, perovskite solar cells (PSCs) have been intensively studies in recent years due to their high-efficiency, low-cost and ease of fabrication. For a typical high-performance PSC, electron transport layer (ETL) plays an important role in selectively extracting and transporting photo-generated electrons from perovskite to the electrode. In this paper, for the first time, we found that a well-organized In2S3 nanoflakes array can be used in PSCs with a high power conversion efficiency (PCE) of 18.22% with less hysteresis. In comparison, PSCs based on TiO2 ETL showed a much lower PCE of 15.70%. Experimental results clearly illustrate that the optimized band structure, enhanced light tapping and low recombination of photo-generated carriers in In2S3 ETL based devices leads to this enhanced performance. Noteworthily, such In2S3 ETLs are simple and solution processable at low-temperature (≤80 °C), which might provide new avenue for low-cost and solution-processed photovoltaics.