Zhang Jin, Hong Hao, Zhang Jincan, Wu Chunchun, Peng Hailin, Liu Kaihui, Meng Sheng
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P.R. China.
State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, P.R. China.
J Phys Chem Lett. 2021 Mar 25;12(11):2886-2891. doi: 10.1021/acs.jpclett.1c00347. Epub 2021 Mar 16.
The capture of photoexcited deep-band hot carriers, excited by photons with energies far above the bandgap, is of significant importance for photovoltaic and photoelectronic applications because it is directly related to the quantum efficiency of photon-to-electron conversion. By employing time-resolved photoluminescence and state-of-the-art time-domain density functional theory, we reveal that photoexcited hot carriers in organic-inorganic hybrid perovskites prefer a zigzag interfacial charge-transfer pathway, ., the hot carriers transfer back and forth between CHNHPbI and graphene electrode, before they reach a charge-separated state. Driven by quantum coherence and interlayer vibrational modes, this pathway at the semiconductor-graphene interface takes about 400 fs, much faster than the relaxation process within CHNHPbI (several picoseconds). Our work provides new insight into the fundamental understanding and precise manipulation of hot carrier dynamics at the complex interfaces, paving the way for highly efficient photovoltaic and photoelectric device optimization.
由能量远高于带隙的光子激发产生的光激发深带热载流子的捕获，对于光伏和光电子应用具有重要意义，因为它直接关系到光子到电子转换的量子效率。通过采用时间分辨光致发光和最先进的时域密度泛函理论，我们揭示了有机-无机杂化钙钛矿中的光激发热载流子倾向于一种锯齿形界面电荷转移途径，即热载流子在达到电荷分离状态之前，在CH₃NH₃PbI₃和石墨烯电极之间来回转移。在量子相干和层间振动模式的驱动下，半导体-石墨烯界面处的这条途径耗时约400飞秒，比CH₃NH₃PbI₃内的弛豫过程（几皮秒）快得多。我们的工作为深入理解和精确操控复杂界面处的热载流子动力学提供了新的见解，为高效光伏和光电器件的优化铺平了道路。
