Li Yifan, Zhao Xinmin, Meng Ni, Dong Shuo, Yan Shan, Yang Man, Sun Changjiu, Li Zhiqiang, Yang Shaopeng, Yuan Mingjian, He Tingwei
Hebei Key Laboratory of Optic-Electronic Information and Materials, Province-Ministry Co-construction Collaborative Innovation Center of Hebei Photovoltaic Technology, College of Physics Science and Technology, Hebei University, Baoding, 071002, China.
College of Chemistry, Nankai University, Tianjin, 300071, China.
Adv Mater. 2025 Jul 18:e05694. doi: 10.1002/adma.202505694.
Mixed-halogen wide-bandgap (WBG) perovskite materials are employed in tandem solar cells (TSCs) due to their continuous tunability of bandgap. However, inhomogeneous halogen phases are often observed in bromine-rich perovskite films, which restricts the performance of WBG perovskite solar cells (PSCs) and TSCs. Here, homogeneous halogen-phase perovskite is proposed to form film by a synchronous halogen-phase transformation strategy. 1,3-Dimethyl-2-imidazolidinone (DMI) is introduced into the perovskite precursor solution, due to its stronger binding energy with lead halide (PbX). The homogeneous DMI-PbX adducted intermediate phase is stable in precursor solution and at spin-coating stage. And it then synchronously transforms into a homogeneous halide-phase perovskite film at the annealing stage. Benefited from efficient carrier extraction and suppressed carrier recombination, the resulting 1.76 eV-bandgap PSC achieves a record power conversion efficiency (PCE) of 21.42% (certified 21.18%) among devices with a bandgap wider than 1.74 eV. Based on the high transmittance of semitransparent-WBG PSC, a 4-terminal all-perovskite TSC achieves a PCE of 29.66%.
混合卤化物宽带隙（WBG）钙钛矿材料因其带隙的连续可调性而被应用于叠层太阳能电池（TSC）中。然而，在富溴钙钛矿薄膜中经常观察到不均匀的卤化物相，这限制了WBG钙钛矿太阳能电池（PSC）和TSC的性能。在此，提出通过同步卤化物相转变策略形成均匀卤化物相钙钛矿薄膜。将1,3-二甲基-2-咪唑啉酮（DMI）引入钙钛矿前驱体溶液中，因为它与卤化铅（PbX）具有更强的结合能。均匀的DMI-PbX加合中间相在前驱体溶液和旋涂阶段是稳定的。然后在退火阶段同步转变为均匀的卤化物相钙钛矿薄膜。得益于高效的载流子提取和抑制的载流子复合，所得带隙为1.76 eV的PSC在带隙大于1.74 eV的器件中实现了创纪录的21.42%（认证值为21.18%）的功率转换效率（PCE）。基于半透明WBG PSC的高透射率，四端全钙钛矿TSC实现了29.66%的PCE。
