Role of Microstructure in the Electron-Hole Interaction of Hybrid Lead-Halide Perovskites.
Role of Microstructure in the Electron-Hole Interaction of Hybrid Lead-Halide Perovskites.
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DOI：
10.1038/nphoton.2015.151
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发表时间：
2015-10-01
期刊：
影响因子：
35
通讯作者：
Petrozza A
中科院分区：
文献类型：
--
作者：
Grancini G;Srimath Kandada AR;Frost JM;Barker AJ;De Bastiani M;Gandini M;Marras S;Lanzani G;Walsh A;Petrozza A
基于混合无机-有机卤化物钙钛矿的太阳能电池已经在一系列架构中展示了高功率转换效率。这些材料中束缚电子-空穴对的存在和稳定性，以及它们在光电器件的优异性能中的作用，仍然是一个有争议的问题。在这里，我们证明，通过结合的光学光谱和多尺度建模作为多晶度和温度的函数，电子-空穴相互作用是敏感的材料的微观结构。长程有序被多晶无序破坏，并且对于较小的晶体发现的静电势的变化抑制激子的形成，而相同组成的较大的晶体表现出明确的激子状态。我们的结论是，制造程序和形态强烈影响钙钛矿行为，自由载流子和激子制度可能，具有强烈的光电器件的影响。
Solar cells based on hybrid inorganic-organic halide perovskites have demonstrated high power conversion efficiencies in a range of architectures. The existence and stability of bound electron-hole pairs in these materials, and their role in the exceptional performance of optoelectronic devices, remains a controversial issue. Here we demonstrate, through a combination of optical spectroscopy and multiscale modeling as a function of the degree of polycrystallinity and temperature, that the electron-hole interaction is sensitive to the microstructure of the material. The long-range order is disrupted by polycrystalline disorder and the variations in electrostatic potential found for smaller crystals suppress exciton formation, while larger crystals of the same composition demonstrate an unambiguous excitonic state. We conclude that fabrication procedures and morphology strongly influence perovskite behaviour, with both free carrier and excitonic regimes possible, with strong implications for optoelectronic devices.