[en] Highlights: • In₂S₃ is utilized as electron transport layer in perovskite solar cells for the first time. • The optimized band structure and enhanced light tapping of In₂S₃ ETL are responsible for the high performance. • A deeper insight into the kinetics of charge transfer in PSCs is proposed. • The low-temperature (≤80 °C) synthesis method may provide new avenue for photovoltaics. 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.