Enomoto Kazushi, Miranti Retno, Liu Jianjun, Okano Rinkei, Inoue Daishi, Kim DaeGwi, Pu Yong-Jin
RIKEN Center for Emergent Matter Science (CEMS) Wako Saitama 351-0198 Japan
Department of Physics and Electronics, Osaka Metropolitan University Osaka 558-8585 Japan
Chem Sci. 2024 Jul 15;15(32):13049-13057. doi: 10.1039/d4sc01769b. eCollection 2024 Aug 14.
Cesium lead halide (CsPbX, X = Cl, Br, or I) perovskite quantum dots (PeQDs) show promise for next-generation optoelectronics. In this study, we controlled the electronic coupling between PeQD multilayers using a layer-by-layer method and dithiol linkers of varying structures. The energy shift of the first excitonic peak from monolayer to bilayer decreases exponentially with increasing interlayer spacer distance, indicating the resonant tunnelling effect. X-ray diffraction measurements revealed anisotropic inter-PeQD distances in multiple layers. Photoluminescence (PL) analysis showed lower energy emission in the in-plane direction due to the electronic coupling in the out-of-plane direction, supporting the anisotropic electronic state in the PeQD multilayers. Temperature-dependent PL and PL lifetimes indicated changes in exciton behaviour due to the delocalized electronic state in PeQD multilayers. Particularly, the electron-phonon coupling strength increased, and the exciton recombination rate decreased. This is the first study demonstrating controlled electronic coupling in a three-dimensional ordered structure, emphasizing the importance of the anisotropic electronic state for high-performance PeQDs devices.
卤化铯铅（CsPbX，X = Cl、Br或I）钙钛矿量子点（PeQDs）在下一代光电子学领域展现出了应用前景。在本研究中，我们使用逐层方法和不同结构的二硫醇连接体来控制PeQD多层膜之间的电子耦合。从单层到双层，第一个激子峰的能量 shift 随着层间间隔距离的增加呈指数下降，这表明了共振隧穿效应。X射线衍射测量揭示了多层中PeQD之间的各向异性间距。光致发光（PL）分析表明，由于面外方向的电子耦合，面内方向的发射能量较低，这支持了PeQD多层膜中的各向异性电子态。温度相关的PL和PL寿命表明，由于PeQD多层膜中电子态的离域，激子行为发生了变化。特别是，电子 - 声子耦合强度增加，激子复合率降低。这是第一项展示在三维有序结构中可控电子耦合的研究，强调了各向异性电子态对于高性能PeQDs器件的重要性。
