The conversion efficiencies reported for Tin (Sn) halide-based perovskite solar cells (PSCs) fall a large gap behind those of lead halide-based PSCs, mainly because of poor film quality of the former. Here we report an efficient strategy based on a simple secondary crystallization growth (SCG) technique to improve film quality for tin halide-based PSCs by applying a series of functional amine chlorides on the perovskite surface. They were discovered to enhance the film crystallinity and suppress the oxidation of Sn²⁺ remarkably, hence reduce trap state density and non-irradiative recombination in the absorber films. Furthermore, the SCG film holds the band levels matching better with carrier transport layers and herein favoring charge extraction at the device interfaces. Consequently, a champion device efficiency of 8.07% was achieved along with significant enhancements in V_oc and J_sc, in contrast to 5.35% of the control device value. Moreover, the SCG film-based devices also exhibit superior stability comparing with the control one. This work explicitly paves a novel and general strategy for developing high performance lead-free PSCs.

据报道，基于锡（Sn）卤化物的钙钛矿太阳能电池（PSC）的转换效率与基于卤化铅的PSC的转换效率相比有很大差距，这主要是因为前者的薄膜质量较差。在这里，我们报告了一种有效的策略，该策略基于简单的二次结晶生长（SCG）技术，通过在钙钛矿表面上应用一系列功能胺氯化物来提高基于卤化锡的PSC的膜质量。发现它们可以增强膜的结晶度并抑制Sn ²⁺的氧化因此，显着降低了吸收体膜中的陷阱态密度和非辐射复合。此外，SCG膜保持的能级与载流子传输层更好地匹配，从而有利于器件界面处的电荷提取。因此，与控制设备值的5.35％相比，冠军设备的效率达到了8.07％，V _oc和J _sc显着提高。而且，基于SCG膜的装置与对照装置相比还显示出优异的稳定性。这项工作明确为开发高性能无铅PSC铺平了新的通用策略。