Ambrosio Francesco, De Angelis Filippo, Goñi Alejandro R
Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Chimiche "Giulio Natta" (CNR-SCITEC), Via Elce di Sotto 8, 06123 Perugia, Italy.
Department of Chemistry and Biology "A. Zambelli", University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, Salerno Italy.
J Phys Chem Lett. 2022 Aug 25;13(33):7731-7740. doi: 10.1021/acs.jpclett.2c01945. Epub 2022 Aug 15.
Metal halide perovskites (MHPs) are solution-processed materials with exceptional photoconversion efficiencies that have brought a paradigm shift in photovoltaics. The nature of the peculiar optoelectronic properties underlying such astounding performance is still controversial. The existence of ferroelectricity in MHPs and its alleged impact on photovoltaic activity have fueled an intense debate, in which unanimous consensus is still far from being reached. Here we critically review recent experimental and theoretical results with a two-fold objective: we argue that the occurrence of ferroelectric domains is incompatible with the A-site cation dynamics in MHPs and propose an alternative interpretation of the experiments based on the concept of ferroelasticity. We further underline that ferroic behavior in MHPs would not be relevant at room temperature or higher for the physics of photogenerated charge carriers, since it would be overshadowed by competing effects like polaron formation and ion migration.
金属卤化物钙钛矿（MHP）是通过溶液处理的材料，具有卓越的光电转换效率，给光伏领域带来了范式转变。这种惊人性能背后奇特的光电特性的本质仍存在争议。MHP中铁电性的存在及其对光伏活性的所谓影响引发了激烈的争论，目前仍远未达成一致共识。在此，我们批判性地回顾了近期的实验和理论结果，目标有两个：我们认为铁电畴的出现与MHP中A位阳离子动力学不相容，并基于铁弹性概念对实验提出了另一种解释。我们进一步强调，对于光生载流子的物理过程而言，MHP中的铁性行为在室温或更高温度下并不相关，因为它会被极化子形成和离子迁移等竞争效应所掩盖。
