Mithrene Is a Self-Assembling Robustly Blue Luminescent Metal–Organic Chalcogenolate Assembly for 2D Optoelectronic Applications

Crystalline metal–organic chalcogenolate assemblies are a class of semiconducting hybrid nanomaterials that consist of well-defined arrays of nanostructured inorganic coordination polymers with a supramolecular lattice of organic ligands. Growing crystals of periodic arrays of nanostructured hybrid chalcogenolates at biphasic liquid–liquid interfaces has been used to prepare semiconducting hybrid materials for potential applications in sensing, catalysis, mechanochemistry, organic light-emitting devices, and photovoltaics. However, a distinct lack of a systematic framework for quantifying the relationship between experimental parameters and the structure–function relationship of the prepared materials has been one of the largest hurdles for the emerging field of hybrid chalcogenolates and related hybrid coordination polymer systems. Here we examine the crystallization of silver benzeneselenolate, coined here as mithrene, at a toluene–water interface and demonstrate that silver ion concentration is the critical variable for controlling the morphology of the semiconducting crystals. Confocal microscopy is used to demonstrate that the blue luminescence of the material is robust across all morphologies. The role of metal ion concentration on the structure and morphology of the hybrid chalcogenolate is considered, and the properties of the crystalline and amorphous products are compared. Grazing-incidence wide-angle X-ray scattering is used to demonstrate that the crystallographic phase of the crystals in sparse layers is uniform across all morphologies. The observation of blue luminescence can be used as a reliable proxy for the crystalline phase in future work. The straightforward synthetic preparation for and robust optoelectronic properties of silver benzeneselenolate make it an ideal model system for the development of device and sensor applications leveraging the emerging class of metal–organic chalcogenolates.