Influence of selenization temperature on synthesis, morphology, and properties of nanostructured CoSe₂ films

Abstract

Nanostructured cobalt selenide (CoSe 2 ) thin films were deposited on a glass substrate using the selenization of Co films at different selenization temperatures (300°C, 400°C, and 500°C) in a pure Se vapor for two hours. The morphology and structure of the as-deposited films shows that the film morphology and crystallinity are affected by the selenization temperature. Increasing the selenization temperature from 300°C to 400°C and 500°C results in a change in the surface and cross sectional morphology. At 300°C, the Co films have an almost amorphous structure, while at temperatures of 400 and 500°C, the Co films have a crystalline nanostructure with bilayered morphology. Optical analyses of the CoSe 2 films at 500°C show a large absorption (α > 1.0 × 10 5 cm −1 ) and a direct band gap (ß1.0 eV).

Method for the Solution Deposition of Phase-Pure CoSe2 as an Efficient Hydrogen Evolution Reaction Electrocatalyst

“…In addition to the discovery of new electrocatalysts, it is also necessary to develop new methods for preparing these catalysts such that they can be robustly deposited on an electrode surface with morphology and structure that are optimizable for maximum utilization with respect to mass and surface area. Current methods for the preparation of these dichalcogenide catalysts are energy intensive, including thermal sulfurization/selenization of e-beam evaporated or sputtered transition-metal thin films and high-pressure solvothermal preparation of bulk or nanostructured dichalcogenides followed by subsequent deposition onto an electrode. − An alternate and less expensive method for the preparation of such electrocatalysts would combine the synthesis and deposition into a single-step process, ideally under ambient pressure, while permitting the use of various electrode substrates and allowing for tunablilty with respect to catalyst loading, composition, and micro- and nanostructuring …”

Engineering phase transformation of cobalt selenide in carbon cages and the phases’ bifunctional electrocatalytic activity for water splitting

“…However, the effect of the different crystal structures on the electrochemical performance has rarely been reported. Moreover, the current methods for preparing these CoSe 2 crystals are usually complicated and energy intensive [8,[20][21][22]. It is therefore urgent to develop a facile and convenient method to prepare CoSe 2 with different crystal structures and explore their effect on the electrochemical performance.…”