Research Projects

Lead halide perovskite nanocrystals are now the most efficient energy materials for both lighting and photovoltaic applications. First report of such nanocrystals appeared in 2015 and thousands of research publications are published within next five years. However, its race as optical material is now slowed down. Apart from phase stability and obtaining near unity photoluminescence quantum yields, from synthesis aspects all other doors are almost blocked. Making core/shell nanostructures and coupling with other materials remained two important areas of research which could not be explored yet. The issue is their ionic nature where A site cations typically make ionic bonds with the crystal and hence, coupling with or making junction with co-valent materials or metal particles remained indeed difficult and may be impossible for now. Neither with any chalcogenides or metal particles, their heteroepitaxially grown with halide perovskites are not reported yet. Hence, this proposal is aimed to understand the chemistry of the interface of the crystal lattice of ionic and covalent crystals. This will adopt some different synthetic approach to get proper facets of ionic lead halide nanocrystals and then different co-valent or metal (0) crystals will be tried to be grown on their surfaces. Success of the same will open a new area of research and would also provide new family of active energy materials. Techniques will be used here the B-site cation exchange during synthesis of transformation of metal halides to perovskites and microscopic imaging will be carried out for locating A+, B2+ and halide ions at the interface. Overall, the proposal will provide to understand (1) the fundamentals on interface bonding of ionic and co-valent nanocrystals in solution and (2) provide new heterostructured materials.