Roy Chris R, Pan Dongxu, Wang Yining, Hautzinger Matthew P, Zhao Yuzhou, Wright John C, Zhu Zihua, Jin Song
Department of Chemistry, University of Wisconsin - Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States.
Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United States.
J Am Chem Soc. 2021 Apr 7;143(13):5212-5221. doi: 10.1021/jacs.1c01573. Epub 2021 Mar 24.
Heterostructures of three-dimensional (3D) halide perovskites are unstable because of facile anion interdiffusion at halide interfaces. Two-dimensional (2D) Ruddlesden-Popper halide perovskites (RPPs) show suppressed and anisotropic ion diffusion that could enable stable RPP heterostructures, yet the direct and general growth of lateral RPP heterostructures remains challenging. Here, we show that halide miscibility in RPPs decreases with perovskite layer thickness (), enabling the formation of sharp halide lateral heterostructures from = 1 and 2 RP lead iodide microplates via anion exchange with hydrogen bromide vapor. In contrast, RPPs with ≥ 3 form more diffuse lateral heterojunctions, more similar to those in 3D perovskites. The anion exchange behaviors are further modulated by the spacer and A-site cations in the RPP structures. These new insights, and kinetic studies of the exchange reactions, enable the preparation of lateral heterostructures from various = 2 RPPs that are more stable against anion interdiffusion and degradation for potential optoelectronic device applications.
三维（3D）卤化物钙钛矿的异质结构由于卤化物界面处阴离子的易扩散而不稳定。二维（2D）Ruddlesden-Popper卤化物钙钛矿（RPPs）表现出抑制的各向异性离子扩散，这可能使RPP异质结构稳定，但横向RPP异质结构的直接和普遍生长仍然具有挑战性。在这里，我们表明，RPPs中卤化物的混溶性随钙钛矿层厚度（）的增加而降低，通过与溴化氢蒸汽进行阴离子交换，能够从 = 1和2的RP碘化铅微板形成尖锐的卤化物横向异质结构。相比之下，≥ 3的RPPs形成的横向异质结更弥散，更类似于3D钙钛矿中的异质结。RPP结构中的间隔阳离子和A位阳离子进一步调节了阴离子交换行为。这些新的见解以及交换反应的动力学研究，使得能够从各种 = 2的RPPs制备横向异质结构，这些异质结构在阴离子互扩散和降解方面更稳定，可用于潜在的光电器件应用。
