Jay B. Patel, King’s College London, London, United Kingdom
Metal halide perovskites have rapidly emerged as a highly adaptable class of optoelectronic materials, recognised for their defect tolerance, straightforward processing, and impressive performance in photovoltaic and light emitting applications. A major strength of these materials is their intrinsic bandgap tunability, which comes from the ease of substituting halides or metal cations within the ABX_₃ lattice. This compositional freedom enables smooth and continuous tuning of optical and electronic properties across the visible spectrum, something that is far more accessible in perovskites than in most conventional semiconductors.
Physical vapour deposition, PVD, offers several advantages for perovskite thin film growth, including excellent uniformity, compatibility with industrial vacuum systems, and tight control over film purity. However, achieving reliable bandgap tuning using PVD is challenging because controlling the fluxes of the different precursors is not straightforward. Variations in vapour pressure, thermal stability, and evaporation behaviour can restrict the accessible composition range or make growth conditions unstable. This has limited how effectively PVD can be used to tune perovskite composition.
In this talk, I will show how we overcome these limitations and achieve the full compositional range of mixed halide perovskites using PVD. I will discuss the resulting structural, optical, and electronic properties of the films, and demonstrate how precise compositional control leads to predictable bandgap shifts, phase stability, and strong optoelectronic performance. These results highlight PVD as a fully tunable and industrially relevant route for high quality perovskite thin films.