Extending Carrier Lifetimes in Lead Halide Perovskites with Alkali Metals by Passivating and Eliminating Halide Interstitial Defects.,Angewandte Chemie International Edition

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Extending Carrier Lifetimes in Lead Halide Perovskites with Alkali Metals by Passivating and Eliminating Halide Interstitial Defects.
Angewandte Chemie International Edition ( IF 16.1 ) Pub Date : 2019-12-24 , DOI: 10.1002/anie.201911615
Lu Qiao ₁ , Wei-Hai Fang ₁ , Run Long ₁ , Oleg V Prezhdo ₂

Affiliation

Defects, such as halide interstitials, act as charge recombination centers, induce degradation of halide perovskites, and create major obstacles to applications of these materials. Alkali metal dopants greatly improve perovskite performance. Using ab initio nonadiabatic molecular dynamics, it is demonstrated that alkalis bring favorable effects. The formation energy of halide interstitials increases by up to a factor of four in the presence of alkali dopants, and therefore, defect concentration decreases. When defects are present, alkali metals strongly bind to them. Halide interstitials introduce mid-gap states that rapidly trap charge carriers. Alkalis eliminate the trap states, helping to maintain high current density. Further to charge trapping, the interstitials accelerate charge recombination. By passivating the interstitials, alkalis make carrier lifetimes up to seven times longer than in defect-free perovskites and up to thirty times longer than in defective perovskites.

中文翻译：

通过钝化和消除卤化物间隙缺陷来延长含碱金属的卤化钙钛矿中铅的使用寿命。

诸如卤化物间隙之类的缺陷充当电荷复合中心，诱发卤化物钙钛矿的降解，并为这些材料的应用造成主要障碍。碱金属掺杂剂极大地改善了钙钛矿的性能。使用从头开始的非绝热分子动力学，证明了碱带来了有利的作用。在存在碱金属掺杂剂的情况下，卤化物间隙的形成能最多增加四倍，因此缺陷浓度降低。当存在缺陷时，碱金属会牢固地与其结合。卤化物间隙物会引入中间能隙状态，从而迅速俘获电荷载流子。碱消除了陷阱状态，有助于维持高电流密度。除电荷捕获外，间隙可加速电荷复合。通过钝化插页式广告，

更新日期：2020-02-14

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