Costas Stoumpos’ research expertise lies in the synthesis and material science of novel halide semiconductors with a perovskite crystal structure, AMX3. The framework crystal structure of the perovskite is amenable to a vast synthetic parameterization and allows for control over the semiconducting properties of the materials by varying the metal ion, M2+, the halide anion, X-, and the non-bonding counteraction A+. The research objective is the development of medium and wide band gap semiconductors (Eg = 1-3 eV) for energy applications such as photovoltaics, light-emitting devices (LEDs), lasers, nonlinear optics (NLO) and radiation detection. The project involves the full arsenal of solid-state and solvothermal synthesis methods and proceeds to the fabrication and evaluation of functional devices in the form of large single-crystals or thin-films. The character of the research is exploratory in nature, targeting new materials among the halide, chalcogenide and pnictide classes of inorganic materials, including hybrid organic-inorganic extended solids. The current directions in the laboratory revolve in the following topics: Low dimensional inorganic semiconductors Polar semiconductors and multiferroic materials Soft inorganic semiconductors