Role of fluoride and fluorocarbons in enhanced stability and performance of halide perovskites for photovoltaics
Role of fluoride and fluorocarbons in enhanced stability and performance of halide perovskites for photovoltaics
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DOI：
10.1103/physrevmaterials.4.120301
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发表时间：
2020-12
影响因子：
3.4
通讯作者：
Benjamin M. Lefler;S. May;A. Fafarman
中科院分区：
文献类型：
--
作者：
Benjamin M. Lefler;S. May;A. Fafarman
氟是电负性最强的元素，其较小的原子尺寸和高度极性的化学键使其在许多材料中发挥着独特而关键的作用。在这篇研究进展中，作者综述了氟在界面处引入时解决卤化物钙钛矿（一类新兴的光伏吸收材料）稳定性和光物理性质方面基本材料问题的潜力。虽然卤化物钙钛矿的电子结构在体相中被认为是耐缺陷的，但表面和晶界处的缺陷由于其对水分和氧气具有更强的反应性，是载流子复合和相降解的位点。氟化物和氟碳化合物可以通过增强晶界处的键合强度以及作为疏水的物理化学屏障来直接防止缺陷。还讨论了一些间接的益处，例如形态和电池能带排列的改善。我们的讨论涵盖了氟化物作为卤化物替代物部分掺入钙钛矿晶格、用氟碳阳离子替代本征阳离子以及分子氟碳化合物的引入。
Fluorine is the most electronegative element and its small size and highly polar bonding enable it to play a unique and vital role in many materials. In this Research Update, the authors review the potential for fluorine, when incorporated at interfaces, to address fundamental materials challenges to the stability and photophysical properties of halide perovskites, a burgeoning class of photovoltaic absorber materials. While the halide perovskite electronic structure is considered to be defect-tolerant in the bulk, defects at surfaces and grain boundaries are sites of carrier recombination and phase degradation due to their greater reactivity towards moisture and oxygen. Fluoride and fluorocarbons can directly prevent defects by increasing the bonding strength at grain boundaries as well as by acting as a hydrophobic physicochemical barrier. Less direct benefits are also discussed, such as morphological and cell band alignment improvements. Our discussion covers partial incorporation in the perovskite lattice of fluoride as a halide substitution and substitution of the native cations for fluorocarbon cations, as well as the inclusion of molecular fluorocarbons.