Funded by an ERC-Advanced Grant (ID: 834431), HELD aims at developping high-efficiency optoelectronic devices based on metal halide perovskites. Thermal vacuum deposition and other industry-compatible methods are used for the fabrication of such thin-film devices which include light-emitting diodes, solar cells, and lasers. Cutting-edge characterization tools such as hyperspectral imaging allow us to unveil the working mechanisms of the different processes involved and optimize the fabrication of these devices.