Fundamental Studies and Applications of 2D Halide Perovskite Heterostructures

Metal halide perovskites are inexpensive semiconductor materials promising for high performance solar cells and light emitting diodes (LEDs) because they are easy to make and tolerant of defects. A fundamental understanding of the factors controlling the carrier transfer mechanisms in heterostructures of halide perovskites is crucial for guiding the synthetic strategies to improve properties and device applications. We developed new methods for synthesizing nanostructures of both three-dimensional (3D) perovskites and two-dimensional (2D) Ruddlesden–Popper (RP) layered perovskites, and using them to create novel and arbitrary heterostructures, such as 2D/3D perovskite heterostructures, vertical 2D/2D heterostructures and lateral 2D heterostructures, with high quality interface and tunable band alignments. We use various structural characterization and time-resolved spectroscopic methods to study the carrier transfer mechanisms between these well-defined 2D and 3D perovskites and between different RP phases. We are trying to fabricate optoelectronic devices using such heterostructures. The excellent properties of these single-crystal perovskite nanostructures of diverse families of perovskite materials with different cations, anions, and dimensionality make them ideal model systems for fundamental physical studies of carrier transport and decay mechanisms and for enabling high performance solar cells, lasers, LEDs, and other optoelectronic applications.