Vogel Dayton J, Kryjevski Andrei, Inerbaev Talgat, Kilin Dmitri S
Department of Chemistry, University of South Dakota , Vermillion, South Dakota 57069, United States.
Department of Physics, North Dakota State University , Fargo, North Dakota 58102, United States.
J Phys Chem Lett. 2017 Jul 6;8(13):3032-3039. doi: 10.1021/acs.jpclett.6b03048. Epub 2017 Jun 27.
Methylammonium lead iodide perovskite (MAPbI) is a promising material for photovoltaic devices. A modification of MAPbI into confined nanostructures is expected to further increase efficiency of solar energy conversion. Photoexcited dynamic processes in a MAPbI quantum dot (QD) have been modeled by many-body perturbation theory and nonadiabatic dynamics. A photoexcitation is followed by either exciton cooling (EC), its radiative (RR) or nonradiative recombination (NRR), or multiexciton generation (MEG) processes. Computed times of these processes fall in the order of MEG < EC < RR < NRR, where MEG is on the order of a few femtoseconds, EC is in the picosecond range, while RR and NRR are on the order of nanoseconds. Computed time scales indicate which electronic transition pathways can contribute to increase in charge collection efficiency. Simulated mechanisms of relaxation and their rates show that quantum confinement promotes MEG in MAPbI QDs.
甲基碘化铅钙钛矿（MAPbI）是一种用于光电器件的很有前景的材料。将MAPbI改性为受限纳米结构有望进一步提高太阳能转换效率。通过多体微扰理论和非绝热动力学对MAPbI量子点（QD）中的光激发动态过程进行了建模。光激发之后会发生激子冷却（EC）、辐射复合（RR）或非辐射复合（NRR），或者多激子产生（MEG）过程。这些过程的计算时间顺序为MEG < EC < RR < NRR，其中MEG在几飞秒量级，EC在皮秒范围内，而RR和NRR在纳秒量级。计算出的时间尺度表明哪些电子跃迁途径有助于提高电荷收集效率。模拟的弛豫机制及其速率表明，量子限域促进了MAPbI量子点中的多激子产生。
