Tin perovskite is rising as a promising candidate to address the toxicity and theoretical efficiency limitation of lead perovskite. However, the voltage and efficiency of tin perovskite solar cells are much lower than lead counterparts. Herein, indene-C₆₀ bisadduct with higher energy level is utilized as an electron transporting material for tin perovskite solar cells. It suppresses carrier concentration increase caused by remote doping, which significantly reduces interface carriers recombination. Moreover, indene-C₆₀ bisadduct increases the maximum attainable photovoltage of the device. As a result, the use of indene-C₆₀ bisadduct brings unprecedentedly high voltage of 0.94 V, which is over 50% higher than that of 0.6 V for device based on [6,6]-phenyl-C61-butyric acid methyl ester. The device shows a record power conversion efficiency of 12.4% reproduced in an accredited independent photovoltaic testing lab.

A 3D structure-mediated growth method is developed to synthesize high quality zero dimensional Cs₄SnX₆ nanocrystals.

The development of high-performance lead-free perovskite solar cells (PSCs) is important to address the environmental concern of lead perovskite. In recent years, tin perovskite solar cells (TPSCs) have been developing quickly and emerging as a promising candidate for high-efficiency lead-free PSCs. In this Perspective, we summarize recent work of our group including the use of a low-dimensional structure, film growth kinetic control, and device engineering. In the end, the challenges in TPSCs and potential strategies toward high-efficiency TPSCs are discussed.