Kim Byunggeol, Park Jeehong, Kang Donghee, Jung Na Eun, Kim Kitae, Ryu Hongsun, Jang Joon Ik, Park Soohyung, Yi Yeonjin
Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea.
Advanced Analysis & Data Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.
Nano Converg. 2025 Jan 13;12(1):1. doi: 10.1186/s40580-024-00473-y.
Two-dimensional halide perovskites are attracting attention due to their structural diversity, improved stability, and enhanced quantum efficiency compared to their three-dimensional counterparts. In particular, Dion-Jacobson (DJ) phase perovskites exhibit superior structural stability compared to Ruddlesden-Popper phase perovskites. The inherent quantum well structure of layered perovskites leads to highly anisotropic charge transport and optical properties. Therefore, controlling the preferred crystal orientation (parallel or perpendicular) is crucial for optimizing device performance. This work presents a rational strategy to control parallel and perpendicular crystal growth in CNHPbI (4AMPPbI)-based DJ phase perovskite thin films. We demonstrate that crystal orientation depends on crystal growth rates, which can be controlled by varying the solvent composition, antisolvent, and annealing temperature. Direct and inverse photoelectron spectroscopy reveals that the electronic structure of 4AMPPbI, including its work function, ionization energy, and electron affinity, is orientation-dependent. Different orientations significantly affect carrier transport as confirmed by single-carrier devices. This study highlights the critical role of crystal orientation in DJ phase perovskites for designing high-performance optoelectronic devices.
二维卤化物钙钛矿因其结构多样性、稳定性提高以及与三维对应物相比增强的量子效率而备受关注。特别是，与Ruddlesden-Popper相钙钛矿相比，Dion-Jacobson (DJ) 相钙钛矿表现出卓越的结构稳定性。层状钙钛矿固有的量子阱结构导致高度各向异性的电荷传输和光学性质。因此，控制择优晶体取向（平行或垂直）对于优化器件性能至关重要。这项工作提出了一种合理的策略来控制基于CNHPbI (4AMPPbI) 的DJ相钙钛矿薄膜中的平行和垂直晶体生长。我们证明晶体取向取决于晶体生长速率，这可以通过改变溶剂组成、反溶剂和退火温度来控制。直接和逆光电子能谱表明，4AMPPbI的电子结构，包括其功函数、电离能和电子亲和势，是取向依赖的。如单载流子器件所证实的，不同取向显著影响载流子传输。这项研究突出了晶体取向在DJ相钙钛矿中对于设计高性能光电器件的关键作用。
