Kennard Rhiannon M, Dahlman Clayton J, Nakayama Hidenori, DeCrescent Ryan A, Schuller Jon A, Seshadri Ram, Mukherjee Kunal, Chabinyc Michael L
Electronics Materials and New Energy Laboratory , Mitsubishi Chemical Corporation , Yokohama R&D Center 1000, Kamoshida-cho, Aoba-ku, Yokohama 227-8502 , Japan.
Department of Chemistry & Biochemistry , University of California Santa Barbara , Santa Barbara , California 93106-9510 , United States.
ACS Appl Mater Interfaces. 2019 Jul 17;11(28):25313-25321. doi: 10.1021/acsami.9b06069. Epub 2019 Jul 3.
Mixed halide hybrid organic-inorganic perovskites have band gaps that span the visible spectrum making them candidates for optoelectronic devices. Transport of the halide atoms in methyl ammonium lead iodide (MAPbI) and its alloys with bromine has been observed in both dark and under illumination. While halide transport upon application of electric fields has received much attention, less is known regarding bromide and iodide interdiffusion down concentration gradients. This work provides an upper bound on the bromide-iodide interdiffusion coefficient in thin films of MAPb(BrI) using a diffusion couples of lateral heterostructures. The upper bound of was extracted from changes in the interface profiles of the heterostructures upon exposure to heat. The stability of thoroughly heated interfacial profiles suggests that the miscibility gap extends to higher temperatures and to a higher fractional composition of bromine than predicted by theory. The results of this work provide guidance for compositions of thermally stable heterostructures of hybrid halide perovskites.
混合卤化物杂化有机-无机钙钛矿具有跨越可见光谱的带隙，这使其成为光电器件的候选材料。在黑暗和光照条件下，均已观察到甲基碘化铅铵（MAPbI）及其与溴的合金中卤原子的迁移。虽然施加电场时卤化物的迁移受到了广泛关注，但关于溴化物和碘化物沿浓度梯度的相互扩散了解较少。这项工作利用横向异质结构的扩散偶，给出了MAPb(BrI)薄膜中溴化物-碘化物相互扩散系数的上限。通过加热后异质结构界面轮廓的变化提取出了 的上限。充分加热后的界面轮廓的稳定性表明，混溶间隙延伸到了比理论预测更高的温度以及更高的溴分数组成。这项工作的结果为混合卤化物钙钛矿热稳定异质结构的组成提供了指导。
