Heterostructured metal halide perovskite nanowires

We will develop heterostructures in metal halide perovskite (MHP) nanowires and use advanced X-ray methods to understand the process.

Heterostructures are the foundation of modern electronic and optoelectronic devices, thanks to their ability to control the electronic band structure.

A new family of semiconductors, MHPs, has in recent years shown excellent performance in various optoelectronic applications.

MHP heterostructures would be highly desirable, but the epitaxial growth used in traditional semiconductors is very difficult in this group of materials, since the liquid precursor solution of the new layer tends to dissolve previous layers.

In this project, we will use anion exchange to create axial (1D) heterostructures by partially converting pregrown nanowires. The process will be studied in situ using advanced X-ray methods. We will primarily study CsPbBr3, which has very strong emission in the challenging green part of the spectrum.

By converting the ends of the nanowires to the higher-bandgap MHP CsPbCl3, we can confine electron and holes in the remaining CsPbBr3 central segment for optimized radiative recombination.

Nanowires are an ideal system for fundamental studies of the anion exchange process, which will be limited to one dimension and easily observed in a side view using micro-PL and TEM. The process will be studied in situ using advanced lab source and synchrotron based X-ray methods.