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Micron-Size Two-Dimensional Methylammonium Lead Halide Perovskites

: Klein, E.; Black, A.; Tokmak, Ö.; Strelow, C.; Lesyuk, R.; Klinke, C.


ACS nano 13 (2019), No.6, pp.6955-6962
ISSN: 1936-0851
ISSN: 1936-086X
Journal Article
Fraunhofer IAP ()

Hybrid lead halide perovskites with 2D stacking structures have recently emerged as promising materials for optoelectronic applications. We report a method for growing 2D nanosheets of hybrid lead halide perovskites (I, Br and Cl), with tunable lateral sizes ranging from 0.05 to 8 μm and a structure consisting of n stacked monolayers separated by long alkylamines, tunable from bulk down to n = 1. The key to obtaining such a wide range of perovskite properties hinged on utilizing the respective lead halide nanosheets as precursors in a hot-injection synthesis that afforded careful control over all process parameters. The layered, quantum-confined (n ≤ 4) nanosheets were comprised of major and minor fractions with differing n. Energy funneling from low to high n (high to low energy) regions within a single sheet, mediated by the length of the ligands between stacks, produced photoluminescent quantum yields as high as 49%. These large, tunable 2D nanosheets could serve as convenient platforms for future high-efficiency optoelectronic devices.