Jiang Zhenfei, Ko Brian, Berry Keith R, Xing Xinxin, Yi Zhenhuan, Sokolov Alexei V, Hu Jonathan, Bao Jiming, Zhang Zhenrong
Institute for Quantum Science and Engineering and Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, United States.
Department of Physics, Baylor University, Waco, Texas 76798, United States.
ACS Omega. 2024 Aug 7;9(33):35744-35756. doi: 10.1021/acsomega.4c04188. eCollection 2024 Aug 20.
Understanding the effects of laser light, water vapor, and energetic electron irradiation on the intrinsic properties of perovskites is important in the development of perovskite-based solar cells. Various phase transition and degradation processes have been reported when these agents interact with perovskites separately. However, detailed studies of their synergistic effects are still missing. In this work, the synergistic effect of three factors (exposure to laser light, water vapor, and e-beam) on the optical and physical properties of two-dimensional (2D) Ruddlesden-Popper (RP) perovskite flakes [(BA)(MA)PbBr] has been investigated in an environmental cell. When the perovskite flakes were subjected to moderate laser irradiation in a humid environment after prior e-beam irradiation, the photoluminescence (PL) peak centered at 480 nm vanished, while a new PL peak centered at 525 nm emerged, grew, and then quenched. This indicates the degradation process of the 2D RP perovskite was a phase transition to a three-dimensional (3D) perovskite [MAPbBr] followed by the degradation of 3D perovskite. The spatial distribution of the 525 nm PL signal shows that this phase-transition process spreads across the flake to the area as far as ∼40 μm from the laser spot. Without humidity, the phase transition happened in the laser-irritated area but did not spread, which suggests that moisture enhanced the ion migration from the laser-scanned area to the rest of the flake and accelerated the phase transition in the nearby area. Experiments with no prior e-beam irradiation show that e-beam irradiation is the key to activating the 2D-3D phase transition. Therefore, when the three factors work synergistically, a conversion from the 2D RP perovskite into the 3D perovskite is not localized and propagates through the perovskite. These findings contribute to our understanding of the complex interactions between external stimuli and perovskite materials, thereby advancing the development of efficient and stable perovskite-based solar cells.
了解激光、水蒸气和高能电子辐照对钙钛矿本征性质的影响，对于基于钙钛矿的太阳能电池的发展至关重要。当这些因素分别与钙钛矿相互作用时，已报道了各种相变和降解过程。然而，关于它们协同效应的详细研究仍然缺乏。在这项工作中，在环境舱中研究了三个因素（激光照射、水蒸气和电子束）对二维（2D）Ruddlesden-Popper（RP）钙钛矿薄片[(BA)(MA)PbBr]光学和物理性质的协同效应。当钙钛矿薄片在预先电子束辐照后于潮湿环境中受到适度激光辐照时，以480nm为中心的光致发光（PL）峰消失，而以525nm为中心的新PL峰出现、增长然后猝灭。这表明二维RP钙钛矿的降解过程是向三维（3D）钙钛矿[MAPbBr]的相变，随后是三维钙钛矿的降解。525nm PL信号的空间分布表明，这种相变过程从薄片扩散到距离激光光斑约40μm的区域。在没有湿度的情况下，相变发生在激光照射区域但没有扩散，这表明水分增强了离子从激光扫描区域向薄片其余部分的迁移，并加速了附近区域的相变。没有预先电子束辐照的实验表明，电子束辐照是激活二维-三维相变的关键。因此，当这三个因素协同作用时，从二维RP钙钛矿到三维钙钛矿的转变不是局部的，而是通过钙钛矿传播的。这些发现有助于我们理解外部刺激与钙钛矿材料之间的复杂相互作用，从而推动高效稳定的基于钙钛矿的太阳能电池的发展。
