Klein, E.E.KleinBlack, A.A.BlackTokmak, Ö.Ö.TokmakStrelow, C.C.StrelowLesyuk, R.R.LesyukKlinke, C.C.Klinke2022-03-062022-03-062019https://publica.fraunhofer.de/handle/publica/25949610.1021/acsnano.9b01907Hybrid 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 mm 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.en668540journal article