College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, P. R. China.
Departments of Chemistry, and Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States.
J Am Chem Soc. 2023 Jun 28;145(25):14112-14123. doi: 10.1021/jacs.3c04412. Epub 2023 Jun 19.
Hybrid organic-inorganic perovskites (HOIPs) contain light hydrogen atoms that exhibit significant nuclear quantum effects (NQEs). We demonstrate that NQEs have a strong effect on HOIP geometry and electron-vibrational dynamics at both low and ambient temperatures, even though charges in HOIPs reside on heavy elements. By combining ring-polymer molecular dynamics (MD) and ab initio MD with nonadiabatic MD and time-dependent density functional theory and focusing on the most studied tetragonal CHNHPbI, we show that NQEs increase the disorder and thermal fluctuations through coupling of the light inorganic cations to the heavy inorganic lattice. The additional disorder induces charge localization and decreases electron-hole interactions. As a result, the nonradiative carrier lifetimes are extended by a factor of 3 at 160 K and 1/3 at 330 K. The radiative lifetimes are increased by 40% at both temperatures. The fundamental band gap decreases by 0.10 and 0.03 eV at 160 and 330 K, respectively. By enhancing atomic motions and introducing new vibrational modes, NQEs strengthen electron-vibrational interactions. Decoherence, determined by elastic scattering, accelerates almost by a factor of 2 due to NQEs. However, the nonadiabatic coupling, driving nonradiative electron-hole recombination, decreases because it is more sensitive to structural distortions than atomic motions in HOIPs. This study demonstrates, for the first time, that NQEs should be considered to achieve an accurate understanding of geometry evolution and charge carrier dynamics in HOIPs and provides important fundamental insights for the design of HOIPs and related materials for optoelectronic applications.
杂化有机-无机钙钛矿 (HOIPs) 中含有轻氢原子，表现出显著的核量子效应 (NQEs)。我们证明，NQEs 对 HOIP 的几何形状和电子-振动动力学具有强烈影响，即使 HOIP 中的电荷位于重元素上，这种影响在低温和环境温度下都很明显。通过结合环聚合物分子动力学 (MD) 和从头算 MD 与非绝热 MD 和含时密度泛函理论，并聚焦于最受研究的四方 CHNHPbI，我们表明，NQEs 通过轻无机阳离子与重无机晶格的耦合，增加无序和热波动。额外的无序会导致电荷局域化并降低电子-空穴相互作用。因此，非辐射载流子寿命在 160 K 时延长了 3 倍，在 330 K 时延长了 1/3。在这两个温度下，辐射寿命都增加了 40%。基带隙分别在 160 和 330 K 时降低了 0.10 和 0.03 eV。通过增强原子运动并引入新的振动模式，NQEs 增强了电子-振动相互作用。由弹性散射决定的退相干由于 NQEs 而几乎加速了 2 倍。然而，由于非绝热耦合对结构变形比原子运动更敏感，因此驱动非辐射电子-空穴复合的非绝热耦合减少。这项研究首次表明，为了准确理解 HOIPs 中的几何形状演化和电荷载流子动力学，应该考虑 NQEs，并为 HOIPs 和相关光电应用材料的设计提供重要的基本见解。
