Metal halide perovskites, with general formula ABX3, consist in a continuous three-dimensional (3D) network of corner sharing metal halide octahedra, with the A cation enclosed in the cubooctahedral cavities. Here, A is a small organic or inorganic cation (e.g MA = methylammonium, Cs+), B is a divalent metallic cation (e.g. Pb2+, Sn2+), and X is a halide (Cl-, Br-, I-).When bigger organic cations are used, low dimensional structures are created, enormously expanding the synthetic possibilities. For example, layered perovskites of the Ruddlesden-Popper series consist in the alternation of organic and inorganic layers allowing the creation two-dimensional (2D) multi quantum well-like structures.
Metal halide perovskite semiconductors possess a unique combination of optoelectronic properties, such as ambipolar carriers transport, high charge-carrier mobility, high room temperature photoluminescence quantum yield at high excitation density, long radiative recombination lifetime (up to hundreds of ns), sharp absorption edges and high absorption coefficient.
However, the low exciton binding energy and trap-mediated recombination of 3D perovskites strongly limit their photoluminescence quantum yield (PLQY) for light-emitting applications.
In this project will engineer advanced perovskite films with high photoluminescence yield, targeting films with mixed dimensionalities (2D/3D multidimensional systems) to obtain the perfect balance between efficient radiative recombination, long radiative lifetime and high mobility.
Material’s suitability for lasing will be assessed through:
After selecting materials with best transport and luminescence properties, the following objectives will be targeted: