Interfacial B-Site Ion Diffusion in All-Inorganic Core/Shell Perovskite Nanocrystals
Shuya Li, Hanjie Lin, Chun Chu, Martin Chandler, Walker MacSwain, Robert W. Meulenberg, John M. Franck, Arindam Chakraborty, Weiwei Zheng
Abstract
High Resolution Image Download MS PowerPoint Slide All-inorganic metal halide perovskites (ABX 3, X = Cl, Br, or I) show great potential for the fabrication of optoelectronic devices, but the toxicity and instability of lead-based perovskites limit their applications. Shell passivation with a more stable lead-free perovskite is a promising strategy to isolate unstable components from the environment as well as a feasible way to tune the optical properties. However, it is challenging to grow core/shell perovskite nanocrystals (NCs) due to the soft ionic nature of the perovskite lattice. In this work, we developed a facile method to grow a lead-free CsMnCl 3 shell on the surface of CsPbCl 3 NCs to form CsPbCl 3 /CsMnCl 3 core/shell NCs with enhanced environmental stability and improved photoluminescence (PL) quantum yields (QYs). More importantly, the resulting core/shell perovskite NCs have color-tunable PL due to B-site ion diffusion at the interface of the core/shell NCs. Specifically, B-site Mn diffusion from the CsMnCl 3 shell to the CsPbCl 3 core leads to a Mn-doped CsPbCl 3 core (i.e., Mn:CsPbCl 3 ), which can turn on the Mn PL at around 600 nm. The ratio of Mn PL and host CsPbCl 3 PL is highly tunable as a function of the thermal annealing time of the CsPbCl 3 /CsMnCl 3 core/shell NCs. While the halide anion exchange for all-inorganic metal halide perovskites has been well-developed for band-gap-engineered materials, interfacial B-site diffusion in core/shell perovskite NCs is a promising approach for both tunable optical properties and enhanced environmental stability.