高等学校化学学报 ›› 2020, Vol. 41 ›› Issue (3): 439-446.doi: 10.7503/cjcu20190701

• 庆祝《高等学校化学学报》复刊40周年专栏 • 上一篇    下一篇

非绝热分子动力学模拟A位阳离子对钙钛矿热载流子弛豫的影响

贺进禄,龙闰,方维海   

  1. 北京师范大学化学学院, 理论与计算光化学教育部重点实验室, 北京 100875
  • 收稿日期:2019-12-23 出版日期:2020-03-10 发布日期:2020-02-07
  • 通讯作者: 龙闰,方维海
  • 作者简介:龙 闰, 男, 博士, 教授, 博士生导师, 主要从事非绝热动力学方法发展及凝聚相材料激发态动力学研究. E-mail: runlong@bnu.edu.cn|方维海, 男, 博士, 教授, 博士生导师, 中国科学院院士, 主要从事非绝热动力学方法发展及其应用研究. E-mail: fangwh@bnu.edu.cn
  • 基金资助:
    国家自然科学基金资助(Nos. 21573022);国家自然科学基金资助(Nos. 21688102);国家自然科学基金资助(Nos. 21590801);国家自然科学基金资助(Nos. 21520102005)

A-site Cation Effects on Hot Carrier Relaxation in Perovskites by Nonadiabatic Molecular Dynamics Simulations

HE Jinlu,LONG Run,FANG Weihai   

  1. College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, China
  • Received:2019-12-23 Online:2020-03-10 Published:2020-02-07
  • Contact: Run LONG,Weihai FANG
  • Supported by:
    † Supported by the National Natural Science Foundation of China(Nos. 21573022);† Supported by the National Natural Science Foundation of China(Nos. 21688102);† Supported by the National Natural Science Foundation of China(Nos. 21590801);† Supported by the National Natural Science Foundation of China(Nos. 21520102005)

摘要:

钙钛矿具有优异的光学和电学性质, 近年来成为太阳能电池领域的研究热点. 大量实验报道钙钛矿热载流子弛豫时间变化顺序为CsPbBr3>MAPbBr3(MA=CH3NH3)>FAPbBr3[FA=HC(NH2)2], 但A位阳离子(Cs +, MA +, FA +)对弛豫快慢的影响机制仍不明确. 采用基于含时密度泛函理论的非绝热动力学方法研究了上述3种钙钛矿热电子和热空穴的能量弛豫动力学, 计算得到的热载流子弛豫时间与实验结果吻合. 结果表明, A位阳离子通过静电和氢键作用影响其与无机Pb—Br骨架的电子-振动耦合, 使非绝热耦合强度遵从FAPbBr3>MAPbBr3>CsPbBr3的变化趋势, 进而使热载流子弛豫时间尺度变化趋势与之相同, 表明合理选择A位阳离子可以优化钙钛矿太阳能电池的性能.

关键词: 钙钛矿, A位阳离子, 热载流子能量弛豫, 非绝热动力学, 含时密度泛函理论

Abstract:

In recent years, perovskites have become a research hotspot in the field of solar cells due to their excellent optical and electrical properties. A large number of experiments reported that hot carries relaxation times follow the trend CsPbBr3>MAPbBr3(MA=CH3NH3)>FAPbBr3[FA=HC(NH2)2]. However, the underlying mechanism of the A-site cation(Cs +, MA +, FA +) effects on the relaxation time remains unclear, the hot electrons and holes relaxation of the three perovskiteswere investigated using time-domain density functional theory combined with nonadiabatic molecular dynamics. The obtained time scales agreed well with experiment. This is because A-site cation affects electronic-vibrational coupling with the inorganic Pb—Br framework via electrostatic interaction and hydrogen bond, leading to the strength of nonadiabatic coupling decreasing from FAPbBr3 to MAPbBr3, to CsPbBr3. As a result, the hot carrier relaxation times decreases as the same trend. The study suggests that rational choice of A-site cations provides an excellent strategy to the optimize the performance of perovskite solar cells.

Key words: Perovskite, A-site cation, Hot carrier energy relaxation, Nonadiabatic molecular dynamics, Time-dependent density functional theory

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