Polyol process synthesis of metal selenide nanomaterials and their photovoltaic application

Abstract

A mixed solvent of monoethanolamine and thioglycolic acid is successfully used to dissolve Se powder to prepare a highly reactive and soluble Se solution at room temperature in air. The as-prepared Se solution is very stable for more than half a year without any observed precipitation even in air. We used the Se precursor solution to synthesize various metal selenide nanomaterials such as Sb₂Se₃ nanorods, CuSe nanoplates and CuInSe₂ nanocrystals by using a facile and environmentally-friendly triethylene glycol process. The structure, morphology, chemical composition and optical properties of the synthesized metal selenide nanomaterials are characterized. Moreover, the CuInSe₂ nanocrystals are used to prepare ethanol-based colloidal ink and then deposited thin films by a dip-coating process. The synthesized CuInSe₂ nanocrystal thin films are annealed at 550 °C in a selenizing atmosphere. A power conversion efficiency of 2.65% has been achieved by using the CuInSe₂ thin films after selenization as a light-absorbing layer under AM 1.5 illumination.