Thickness-dependent carrier lifetime and mobility for MAPbBr3 single crystals. (August 2020)

• Record Type: Journal Article
• Authors: Xing, J.; Zou, Y.; Zhao, C.; Yu, Z.; Shan, Y.; Kong, W.; Zheng, X.; Li, X.; Yu, W.; Guo, C.
• Is Part Of: Materials today physics. Volume 14(2020)
• Publication Date: 2020-08
• Subjects: Dynamics -- Carrier mobility -- Perovskite -- Thickness -- Transport; Materials science -- Periodicals; Physics -- Periodicals; Electronic journals; 530.41
• DOI: 10.1016/j.mtphys.2020.100240
• Languages: English
• ISSNs: 2542-5293

Abstract

Abstract: Carrier transfer is a key process for perovskite-based photoelectric conversion. It has a close relationship with grain boundaries, grain size, and contact layers. Understanding this relationship is of great significance for revealing the inherent characteristics of perovskite materials and for devices optimization. However, the dependence of carrier transfer characteristics (including carrier lifetime and mobility) on thickness is less studied, although which is a key issue for almost all perovskite material devices. Here we find that as the thickness of MAPbBr3 perovskite single crystal (PSC) increases from 1.47 μm to 10.55 μm, the carrier lifetime of MAPbBr3 decreases from 70 ns to 30 ns, and the carrier mobility decreases from 97 cm 2 V −1 s −1 to 57 cm 2 V −1 s −1, but they become constant in very thick samples. In addition, it was found that as the crystal thickness increased from 1.47 μm to 10.55 μm, the surface layer range gradually increased from 12 nm to 31 nm. The surface recombination velocity and surface defect (trap) density further confirmed that the thin PSC exhibited a small surface layer range. Finally, a three-layer carrier transmission model of PSC is proposed. This research provides guidance for the optimal design of PSC optoelectronic devices. Graphical abstract: Exploring carrier transfer properies in MAPbBr3 single crystal (MPB SCs) is significant for optimizing devices performance. The carrier lifetime and mobility in MPB SCs both show single exponential decay with crystal thickness increasing from 1.47 μm to 10.55 μm and remains stable after that. The trend is attributed to gradually expanding of surface layer and explains why perovskite thin SCs shows good carrier transfer property for optoelectronics. Image 1 Highlights: The dependence of carrier transfer properties on perovskite thickness is explored. Carrier lifetime and mobility both show exponential decay with crystal thickness. The surface layer range gradually increased with crystal thickness. The turning point of properties from thin films to bulk is around 10.55 μm. A three-layer carrier transfer model of MAPbBr3 single crystal is proposed.