Proceedings of September Meeting 2016 (NFM16)
Publication date: 14th June 2016
Colloidal cesium lead halide perovskite nanocrystals (NCs) have been shown recently to possess outstanding optical properties with photoluminescence quantum yields (PL QYs) about 90%, high color purity and compositional tunability of the emission wavelength [1]. Herein we show a new synthetic approach to halide perovskite NCs, namely direct template-assisted growth in mesoporous materials. Template-assisted synthesis allows production of NCs with unprecedented monodispersity and reproducibility of the size. Though this approach didn’t find wide application for conventional semiconductor NCs we show here that it should be reconsidered for new halide perovskite NCs.
Generality of this approach is approved for 2.5-50 nm methylammonium and cesium lead halide NCs. Wide size range and same morphology of obtained NCs allowed to study quantum-size effect on optical properties of perovskite NCs. NCs of optimal size and composition show photoluminescence quantum yield up to 52.4% and long-term stability of the optical properties without any ligands.
Obtained composite microparticles with lead halide perovskite NCs can be further processed by dispersion in apolar solvents while luminescence efficiency of the NCs is preserved. This approach allows simple and easily scalable production of uniform NC films with ±2 nm reproducibility of emission wavelength, high color purity, intrinsic haze and possibility of multivariant compositional/size PL tuning. Furthermore, such films double protect perovskite NCs: by polymer matrix and templating microparticles. Such characteristics are much desired for backlight light emitting devices (LEDs) utilizing semiconductor NCs as light emitters.
1. Protesescu, L.; Yakunin, S.; Bodnarchuk, M. I.; Krieg, F.; Caputo, R.; Hendon, C. H.; Yang, R. X.; Walsh, A.; Kovalenko, M. V. Nano Lett. 2015, 15, (6), 3692-3696.