Operando多维光谱揭示钙钛矿太阳能电池中A位依赖的载流子冷却
Operando multidimensional spectroscopy reveals A-site-dependent carrier cooling in perovskite solar cells
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中文总结 AI 辅助
本研究利用PC-2DES解析不同组成钙钛矿太阳能电池的载流子冷却，揭示其速率依赖A位阳离子，为优化光伏性能提供依据。
中文摘要 AI 辅助
理解工作钙钛矿太阳能电池中光生载流子如何耗散多余能量，对于将超快光物理与光伏功能关联起来，并为下一代电池结构的设计提供原理至关重要。本研究采用光电流检测二维电子光谱（PC-2DES），对完全封装的工作金属卤化物钙钛矿太阳能电池中能量依赖的载流子弛豫进行解析。通过对比结构相同但吸光层组成不同的器件——MAPbI₃、混合FAMA以及FAPbI₃，本研究直接追踪光激发载流子从初始占据的高能态向低能带边态的再分布过程。多维光电流响应揭示了类级联的带内冷却过程，其速率强烈依赖于吸光层组成：MA基器件中弛豫最慢，混合阳离子器件中弛豫速率居中，FA基器件中弛豫最快。结合声子介导的带内散射并补充唯象多体贡献的简化动力学模型，能够捕捉主要的能量依赖趋势。这些结果确立了作用检测多维光谱作为器件级超快能量耗散探针的价值，并表明钙钛矿组成的细微变化可显著改变电荷提取前的载流子弛豫路径。
英文摘要
Understanding how photogenerated carriers dissipate excess energy in operating perovskite solar cells is essential for connecting ultrafast photophysics with photovoltaic function and provides design principles for engineering next-generation cell architectures. Here we use photocurrent-detected two-dimensional electronic spectroscopy (PC-2DES) to resolve energy-dependent carrier relaxation in fully encapsulated, functioning metal halide perovskite solar cells. By comparing devices with identical architecture but different absorber compositions - MAPbI3, mixed FAMA, and FAPbI3 - we directly follow the redistribution of photoexcited carriers from initially populated high-energy states toward lower-energy band-edge states. The multidimensional photocurrent response reveals a cascade-like intraband cooling process whose rate depends strongly on absorber composition, with the slowest relaxation in MA-based devices, intermediate behaviour in mixed-cation devices, and fastest relaxation in FA-based devices. A reduced kinetic model incorporating phonon-mediated intraband scattering, supplemented by a phenomenological many-body contribution, captures the main energy-dependent trends. These results establish action-detected multidimensional spectroscopy as a device-level probe of ultrafast energy dissipation and show that subtle changes in perovskite composition can substantially reshape the carrier relaxation pathways that precede charge extraction.
