Kim Jiyoon, Ghosh Soumyadeep, Smith Nicholas W G, Liu Sunhao, Dou Yixuan, Slebodnick Carla, Khodaparast Giti A, Qian Jin, Quan Lina
Department of Chemistry, Virginia Tech, Blacksburg, VA, 24061, USA.
Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
Adv Mater. 2025 Jun;37(25):e2406274. doi: 10.1002/adma.202406274. Epub 2024 Oct 23.
Hybrid metal-halide perovskites and their derived materials have emerged as the next-generation semiconductors with a wide range of applications, including photovoltaics, light-emitting devices, and other optoelectronics. Over the past decade, numerous single-crystalline perovskite derivatives have been synthesized and developed. However, the synthetic methods for these derivatives mainly rely on acidic crystallization conditions. This approach leads to crystals comprising metal halide building blocks, which show problematic stability when directly exposed to water. In this study, a methodology is developed for synthesizing hybrid metal-halide compounds using lead iodide and the zwitterionic bifunctional molecule cysteamine (CYS), to form various perovskitoid structures under a broad pH range. Interestingly, the different pH conditions alter the coordination environment of lead halides, leading to lead-sulfide and lead-nitride covalent bond formation. This modification significantly enhances their stability when in direct contact with water, lasting for months. Photoluminescence measurements and first principal density functional theory (DFT) calculations reveal that the perovskitoids synthesized under basic and acidic pH conditions exhibit a direct bandgap nature, while those synthesized under neutral conditions display an indirect bandgap. This approach opens new avenues for manipulating synthetic methods to develop water-stable hybrid semiconductors suitable for a wide range of applications, such as solid-state light emitters.
混合金属卤化物钙钛矿及其衍生材料已成为具有广泛应用的下一代半导体，包括光伏、发光器件和其他光电器件。在过去十年中，大量单晶钙钛矿衍生物被合成和开发。然而，这些衍生物的合成方法主要依赖于酸性结晶条件。这种方法导致晶体由金属卤化物结构单元组成，当直接暴露于水时表现出稳定性问题。在本研究中，开发了一种使用碘化铅和两性离子双功能分子半胱胺（CYS）合成混合金属卤化物化合物的方法，以在较宽的pH范围内形成各种类钙钛矿结构。有趣的是，不同的pH条件改变了卤化铅的配位环境，导致形成硫化铅和氮化铅共价键。这种改性显著提高了它们与水直接接触时的稳定性，可持续数月。光致发光测量和第一性原理密度泛函理论（DFT）计算表明，在碱性和酸性pH条件下合成的类钙钛矿表现出直接带隙性质，而在中性条件下合成的类钙钛矿表现出间接带隙。这种方法为操纵合成方法以开发适用于广泛应用（如固态发光体）的水稳定混合半导体开辟了新途径。
