Even though good emission properties make bulk metal halide perovskites natural candidates for efficient light-emitting devices, it is well known that these materials have a limited photoluminescence (PL) quantum yield, due to their small exciton binding energy and to the presence of mobile ion defects. The efficiency of light-emitting devices based on perovskites may be improved by synthesizing two-dimensional (2D), layered materials, which have a much larger exciton binding energy but are still prone to defect formation. The first two goals of the present project will thus be represented by the investigation of the effects of H irradiation on the optical properties of bulk and layered metal halide perovskites. Over the years, the hydrogenation of semiconductors has proven to be an invaluable experimental tool to tune and improve the properties of semiconductors, and preliminary results indeed suggest that H irradiation of bulk perovskites has beneficial effects on the optical properties of these materials. As it regards layered perovskites, however, it is important to note that recent attempts to hydrogenate semiconductors with a similar structure, such as transition-metal dichalcogenides (TMDs) and hexagonal boron nitride (hBN), wherein 2D crystalline layers are held together by weak van der Waals forces, resulted in the accumulation of H2 molecules underneath the first few crystal layers, leading to the formation of micrometer-sized domes that dramatically alter the morphology and the strain state of the material. A further goal of this project will thus be the verification of whether H irradiation of layered perovskites also leads to the formation of similar domes. Finally, the ultimate goals of the present project will be represented by the fabrication of 2D heterostructures, based on the stacking of layered perovskites on top of TMD and hBN microdomes, and on the investigation of the effects that such curved templates have on the strain state of the system.
