Alarousu Erkki, El-Zohry Ahmed M, Yin Jun, Zhumekenov Ayan A, Yang Chen, Alhabshi Esra, Gereige Issam, AlSaggaf Ahmed, Malko Anton V, Bakr Osman M, Mohammed Omar F
KAUST Solar Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology , Thuwal 23955-6900, Kingdom of Saudi Arabia.
Saudi Aramco Research & Development Center , Dhahran 31311, Kingdom of Saudi Arabia.
J Phys Chem Lett. 2017 Sep 21;8(18):4386-4390. doi: 10.1021/acs.jpclett.7b01922. Epub 2017 Aug 31.
Organic-inorganic hybrid perovskite materials have recently evolved into the leading candidate solution-processed semiconductor for solar cells due to their combination of desirable optical and charge transport properties. Chief among these properties is the long carrier diffusion length, which is essential to optimizing the device architecture and performance. Herein, we used time-resolved photoluminescence (at low excitation fluence, 10.59 μJ·cm upon two-photon excitation), which is the most accurate and direct approach to measure the radiative charge carrier lifetime and diffusion lengths. Lifetimes of about 72 and 4.3 μs for FAPbBr and FAPbI perovskite single crystals have been recorded, presenting the longest radiative carrier lifetimes reported to date for perovskite materials. Subsequently, carrier diffusion lengths of 107.2 and 19.7 μm are obtained. In addition, we demonstrate the key role of the organic cation units in modulating the carrier lifetime and its diffusion lengths, in which the defect formation energies for FA cations are much higher than those with the MA ones.
有机-无机杂化钙钛矿材料由于其理想的光学和电荷传输特性的结合，最近已发展成为用于太阳能电池的领先的溶液处理半导体候选材料。这些特性中最主要的是长载流子扩散长度，这对于优化器件结构和性能至关重要。在此，我们使用了时间分辨光致发光（在低激发通量下，双光子激发时为10.59 μJ·cm），这是测量辐射电荷载流子寿命和扩散长度的最准确、最直接的方法。已记录到FAPbBr和FAPbI钙钛矿单晶的寿命分别约为72 μs和4.3 μs，这是迄今为止报道的钙钛矿材料中最长的辐射载流子寿命。随后，获得了107.2 μm和19.7 μm的载流子扩散长度。此外，我们证明了有机阳离子单元在调节载流子寿命及其扩散长度方面的关键作用，其中FA阳离子的缺陷形成能远高于MA阳离子的缺陷形成能。
