Zhang Zhen-Yu, Wang Hai-Yu, Zhang Yan-Xia, Hao Ya-Wei, Sun Chun, Zhang Yu, Gao Bing-Rong, Chen Qi-Dai, Sun Hong-Bo
State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun, 130012, People's Republic of China.
Center of Interface Dynamics for Sustainability, Institute of Materials, China Academy of Engineering Physics, 596 Yinhe Road, Chengdu 610200, People's Republic of China.
Sci Rep. 2016 Jun 1;6:27286. doi: 10.1038/srep27286.
Hybrid metal halide perovskites have been paid enormous attentions in photophysics research, whose excellent performances were attributed to their intriguing charge carriers proprieties. However, it still remains far from satisfaction in the comprehensive understanding of perovskite charge-transport properities, especially about trap-assisted recombination process. In this Letter, through time-resolved transient absorption (TA) and photoluminescence (PL) measurements, we provided a relative comprehensive investigation on the charge carriers recombination dynamics of CH3NH3PbBr3 (MAPbBr3) perovskite films and quantum dots (QDs), especially about trap-assisted recombination. It was found that the integral recombination mode of MAPbBr3 films was highly sensitive to the density distribution of generated charge carriers and trap states. Additional, Trap effects would be gradually weakened with elevated carrier densities. Furthermore, the trap-assisted recombination can be removed from MAPbBr3 QDs through its own surface passivation mechanism and this specialty may render the QDs as a new material in illuminating research. This work provides deeper physical insights into the dynamics processes of MAPbBr3 materials and paves a way toward more light-harvesting applications in future.
杂化金属卤化物钙钛矿在光物理研究中受到了广泛关注，其优异性能归因于其有趣的电荷载流子特性。然而，在对钙钛矿电荷传输特性的全面理解方面，尤其是关于陷阱辅助复合过程，仍远不能令人满意。在本信函中，通过时间分辨瞬态吸收（TA）和光致发光（PL）测量，我们对CH3NH3PbBr3（MAPbBr3）钙钛矿薄膜和量子点（QDs）的电荷载流子复合动力学，特别是陷阱辅助复合，进行了相对全面的研究。结果发现，MAPbBr3薄膜的整体复合模式对所产生电荷载流子和陷阱态的密度分布高度敏感。此外，随着载流子密度的升高，陷阱效应会逐渐减弱。此外，通过其自身的表面钝化机制，可以消除MAPbBr3量子点中的陷阱辅助复合，这种特性可能使量子点成为照明研究中的一种新材料。这项工作为MAPbBr3材料的动力学过程提供了更深入的物理见解，并为未来更多的光捕获应用铺平了道路。
