Dopant Control of Electron–Hole Recombination in Cesium–Titanium Halide Double Perovskite by Time Domain Ab Initio Simulation: Codoping Supersedes Monodoping,The Journal of Physical Chemistry Letters

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Dopant Control of Electron–Hole Recombination in Cesium–Titanium Halide Double Perovskite by Time Domain Ab Initio Simulation: Codoping Supersedes Monodoping
The Journal of Physical Chemistry Letters ( IF 4.8 ) Pub Date : 2018-11-24 00:00:00 , DOI: 10.1021/acs.jpclett.8b03356
Lu Qiao ₁ , Wei-Hai Fang ₁ , Run Long ₁

Affiliation

Using nonadiabatic (NA) molecular dynamics combined with time domain density functional theory, we simulate electron–hole recombination in pristine and doped inorganic Pb-free double perovskite Cs₂TiBr₆. We show that replacing the titanium and/or bromine with silicon and/or chlorine extends the charge carrier lifetime. Importantly, dopants avoid deep traps despite the fact that they do not change the fundamental band gap of Cs₂TiBr₆, and they decrease the NA electron–phonon coupling and accelerate decoherence arising from the reduced overlap of electron and hole wave functions as well as fast phonon modes induced by light dopants, respectively, suppressing electron–hole recombination. More importantly, codoping can reduce the formation energy of silicon and achieve higher doping concentration, potentially increasing the lifetime further. Our study suggests a rational strategy to reduce energy losses by codoping in design of high-performance all-inorganic Pb-free perovskite solar cells.

中文翻译：

时域从头算模拟：铯-卤化铯双层钙钛矿中电子-空穴复合的掺杂剂控制：共掺杂取代单掺杂

使用非绝热（NA）分子动力学与时域密度泛函理论相结合，我们模拟了原始和掺杂的无机无铅双钙钛矿Cs ₂ TiBr _6中的电子-空穴复合。我们表明，用硅和/或氯代替钛和/或溴可延长电荷载流子的寿命。重要的是，尽管掺杂剂不会改变Cs ₂ TiBr ₆的基带隙，但它们应避免形成深陷阱。，它们分别降低了电子和声子的重叠，以及由于轻掺杂剂引起的快速声子模式而减少的NA电子-声子耦合，并加速了退相干，从而抑制了电子-空穴的复合。更重要的是，共掺杂可以降低硅的形成能并获得更高的掺杂浓度，从而有可能进一步延长寿命。我们的研究提出了一种合理的策略，可以通过共掺杂高性能全无机无铅钙钛矿太阳能电池来减少能量损失。

更新日期：2018-11-24

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