In the construction of high performance planar perovskite solar cells (PSCs), the modification of compact TiO₂ layer and engineering of perovskite/TiO₂ interfaces are essential for efficient electron transfer and retarded charge recombination loss. In this work, a facile and effective strategy is developed to modify the surface of compact TiO₂ layer by TiCl₄-TiCl₃ mixture treatment. Compared with conventional sole TiCl₄, the TiCl₄-TiCl₃ treatment takes the advantage of accelerated and controlled hydrolysis of TiCl₃, therefore TiO₂ with dominating anatase phase and moderate roughness is obtained to facilitate the growth of CsPbI₂Br perovskite layer with high quality. Furthermore, the oxidation-driven hydrolysis of TiCl₃ component results in surface Cl doping that facilitates interfacial electron transfer with retarded recombination loss. The average power conversion efficiency (PCE) of carbon-based CsPbI₂Br planar PSCs based on TiCl₄-TiCl₃ treatment increases to 14.18% from the intial 13.04% based on conventional sole TiCl₄ treatment. The champion PSC exhibits a PCE of 14.46% (V_oc = 1.28 V, J_sc = 14.21 mA/cm², and FF = 0.794), which is one of the highest PCEs for carbon-based CsPbI₂Br PSCs.

在高性能平面钙钛矿太阳能电池 (PSC) 的构建中，致密 TiO ₂层的改性和钙钛矿/TiO ₂界面的工程化对于有效的电子转移和延迟电荷复合损失至关重要。在这项工作中，开发了一种简便有效的策略，通过 TiCl ₄ -TiCl ₃混合物处理对致密的 TiO ₂层表面进行改性。与传统的单独TiCl ₄相比，TiCl ₄ -TiCl ₃处理利用了TiCl ₃加速和可控水解的优点，因此TiO ₂获得了占主导地位的锐钛矿相和适度的粗糙度，以促进高质量的 CsPbI ₂ Br 钙钛矿层的生长。此外，TiCl ₃组分的氧化驱动水解导致表面Cl掺杂，促进界面电子转移并延迟复合损失。基于TiCl ₄ -TiCl ₃处理的碳基CsPbI ₂ Br平面PSC的平均功率转换效率（PCE）从基于传统单独TiCl ₄处理的初始13.04%增加到14.18% 。冠军 PSC 的 PCE 为 14.46% ( V _oc = 1.28 V, J _sc = 14.21 mA/cm ², FF = 0.794)，这是碳基 CsPbI ₂ Br PSC的最高 PCE 之一。