Premium
Edge Effect on the Population of Free Carriers and Excitons in Single‐Crystal CH 3 NH 3 PbBr 3 Perovskite Nanomaterials
Author(s) -
Zhang ZhenYu,
Yu Kuai,
Wang GuoPing
Publication year - 2019
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.201900216
Subject(s) - perovskite (structure) , exciton , materials science , photoluminescence , single crystal , hysteresis , charge carrier , crystal (programming language) , optoelectronics , excited state , condensed matter physics , nanotechnology , analytical chemistry (journal) , crystallography , physics , chemistry , atomic physics , chromatography , computer science , programming language
Abstract The spatial distribution of free carriers and excitons in perovskite micro‐/nanostructures is currently a major topic of debate. They have been reported to coexist with spatial separation in individual perovskite grains and films. It is revealed that free carriers and excitons in single‐crystal CH 3 NH 3 PbBr 3 perovskite microplatelets can spatially overlap; however, the distribution is such that the edges can be entirely occupied by the former, while the interior is occupied only by the latter. This is further confirmed in single‐crystal CH 3 NH 3 PbBr 3 perovskite microstrips, in which only free carriers are observed. These results may be attributable to electrostatic potential fluctuations on the edges, which can promote electron–hole separation so that they do not bind to form excitons. Microscopic I–V measurements demonstrate that the microplatelet edges and the microstrips show current densities of more than 260 and 340 A cm −2 in a dark environment under 1.2 V bias voltage, respectively. It is suggested that these findings mean that such microstructures hold promise for the development of novel perovskite micro‐/nanostructure‐based optoelectronic devices with interesting photoconductive properties such as high photoluminescence intensity, longer excited‐state lifetime, high conductivity, large saturation current densities, and suppressed hysteresis effects (smaller open voltages).