Yin Zixi, Leng Jing, Wang Shiping, Liang Guijie, Tian Wenming, Wu Kaifeng, Jin Shengye
State Key Laboratory of Molecular Reaction Dynamics and Dynamics Research Center for Energy and Environmental Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
J Am Chem Soc. 2021 Mar 31;143(12):4725-4731. doi: 10.1021/jacs.1c00424. Epub 2021 Mar 18.
Two-dimensional (2D) layered perovskites are naturally formed multiple quantum-well (QW) materials, holding great promise for applications in many optoelectronic devices. However, the further use of 2D layered perovskites in some devices is limited by the lack of QW-to-QW carrier transport/transfer due to the energy barrier formed by the insulating ligands between QWs. Herein, we report an Auger-assisted electron transfer between adjacent QWs in (CHNH)PbI 2D perovskites particularly with = 12 and 18, where the electron energy barrier () is similar to the QW band gap energy (). This Auger-assisted QW-to-QW electron transfer mechanism is established by the observation of a long-lived and derivative-like transient absorption feature, which is a signature of the quantum confined Stark effect induced by the electron-hole separation (thus an internal electric field) between different QW layers. Our finding provides a new guideline to design 2D perovskites with an optically tunable QW-to-QW charge transport property, advancing their applications in optoelectronics and optical modulations.
二维（2D）层状钙钛矿是天然形成的多量子阱（QW）材料，在许多光电器件中具有广阔的应用前景。然而，由于量子阱之间的绝缘配体形成的能垒，二维层状钙钛矿在某些器件中的进一步应用受到量子阱间载流子传输/转移缺乏的限制。在此，我们报道了在（CHNH）PbI 2D钙钛矿中，特别是n = 12和18时，相邻量子阱之间的俄歇辅助电子转移，其中电子能垒（ΔE）类似于量子阱带隙能量（Eg）。这种俄歇辅助的量子阱间电子转移机制是通过观察到一种长寿命且类似导数的瞬态吸收特征而建立的，这是由不同量子阱层之间的电子 - 空穴分离（从而产生内电场）引起的量子限制斯塔克效应的标志。我们的发现为设计具有光学可调量子阱间电荷传输特性的二维钙钛矿提供了新的指导方针，推动了它们在光电子学和光调制中的应用。
