Interface engineering is generally requisite for highly efficient perovskite solar cells (PSCs). However, the current interface engineering methods inevitably introduce extra modifier layers into PSCs, which not only complex the configurations and fabrication procedures, but also increase the production cost of PSCs. Herein, we propose an interface engineering strategy for PSCs by controlling the nature of Lead halide perovskite films, and specifically their interfacial grain facets. In detail, a solution-mediated secondary growth (SSG) technology is demonstrated to tailor interfacial grain facets in CH₃NH₃PbI₃ PSC. The precise tailoring ability of interfacial grain facets is achieved by controlling SSG temperature. When it is optimized to 60 °C, interfacial grains of CH₃NH₃PbI₃ film can be fully transform from dodecahedral-shaped ones enclosed by (100) and (112) facets to the cubic-shaped ones enclosed by (110) and (002) facets, while maintaining the film's crystalline phase and composition. More importantly, such transitions are accompanied by significantly improved average PCE from 16.51 ± 0.64% to 18.40 ± 0.67% for the optimized CH₃NH₃PbI₃ PSCs, benefiting from the greatly suppressed recombination and enhanced extraction of carriers.

界面工程通常是高效钙钛矿太阳能电池（PSC）所必需的。然而，目前的界面工程方法不可避免地在PSC中引入了额外的改性剂层，这不仅使配置和制造过程变得复杂，而且还增加了PSC的生产成本。本文中，我们通过控制卤化钙钛矿型铅钙薄膜的性质，特别是它们的界面晶粒面，提出了PSC的界面工程策略。详细地，已证明了溶液介导的二次生长（SSG）技术可在CH ₃ NH ₃ PbI _3中修整界面晶粒面PSC。通过控制SSG温度，可以实现界面晶面的精确裁切能力。当优化到60°C时，CH ₃ NH ₃ PbI ₃膜的界面晶粒可以从（100）和（112）面包围的十二面体形状完全转变为（110）和（110）面包围的立方形状。 （002）面，同时保持膜的结晶相和组成。更重要的是，这种转变伴随着优化的CH ₃ NH ₃ PbI ₃ PSC的平均PCE显着提高，从16.51±0.64％增至18.40±0.67％，这得益于极大地抑制了重组并增强了载体的提取。