Facile one-pot synthesis of photoresponsive Cu1.8S and CuInS2 nanostructures aided by Cu-pyrimidylthiolate molecular precursor

Copper-based binary and ternary sulfides have attracted significant attention due to their excellent photo-physical properties, making them highly promising for high-performance energy harvesting and storage devices. This study focuses on the synthesis and structural characterization of an air-stable hexanuclear Cu-pyrimidylthiolate cluster complex which serves as an efficient single-source precursor for the preparation of Cu 1.8 S nanocrystals. Furthermore, coupling the molecular precursor with suitable indium source resulted in a facile one-pot pathway for the preparation of technologically important, copper-based ternary CuInS₂, nanocrystals. The crystal structure, phase purity, and compositions of the nanostructures were confirmed using PXRD, XPS, EDS, and area elemental mapping. Electron microscopic studies revealed the formation of polygonal and hexagonal morphology with varied size in Cu 1.8 S and CuInS₂ nanocrystals respectively. UV-Vis diffuse reflectance spectroscopy showed a slight blue shift in the band gap of the nanostructures compared to their bulk counterparts which can be attributed to quantum confinement or surface lattice distortion effects. The band gap of the pristine nanocrystals along with high photocurrent and stable photo-switching characteristics suggest that they can serve as suitable electrode material for optoelectronic and photodetector devices. Facile synthesis of photoresponsive binary Cu 1.8 S and ternary CuInS 2 nanostructures has been achieved through the cluster complex [Cu(dmpymS)] 6 ∙½ H 2 O under mild thermolysis conditions. • A novel sulfur bridged copper cluster complex was prepared and structurally characterized. • The cluster complex was employed as a precursor for the preparation of non-stoichiometric Cu1.8S nanopolygons. • The cluster complex was found to be useful in preparing ternary CuInS2 hexagonal sheets. • The binary and ternary sulfides exhibit high photoresponse and photostability.