Accessing copper selenide nanostructures through a 1D coordination polymer of copper(ii) with 4,4′-dipyridyldiselenide as a molecular precursor

Abstract

Copper selenide nanostructures have attracted growing attention due to their potential application in cost effective and sustainable solar cells and photocatalysis. This study describes the facile conversion of a new one dimensional copper(II) coordination polymer constructed from 4,4′-dipyridyldiselenide (1D-CupySe) into copper selenide nanostructures. The structure of 1D-CupySe elucidated from single crystal XRD revealed the formation of a one-dimensional zig-zag chain of the [{Cu₂(μ(O,O′)-OAc)₄}(μ(N,N′)-4,4′-py₂Se₂)] repeating unit. Interestingly, the diselenide linkage remains intact in the polymer which can be readily cleaved under mild thermolytic conditions, thereby facilitating intra-molecular selenium transfer to the Cu(II) center. The solvent assisted breakdown of 1D-CupySe revealed the formation of Cu_2−xSe nanostructures. Importantly, different compositions of Cu_2−xSe (Cu_1.75Se and Cu₂Se) could be isolated by the choice of solvent. The as-prepared nanostructures have been thoroughly characterized by pXRD, EDS, electron microscopy and DRS for assessing their phase purity, crystal structure, elemental composition, morphology and optical properties. The nanostructures exhibit a narrow band gap in the range of 2.3–2.45 eV. Prototype photoelectrochemical cells fabricated using the nanostructures exhibit high current generation which makes them suitable alternatives for non-toxic and low-cost photon absorber materials.