Fabrication of transparent conducting films composed of In3+ doped CuS and their application in flexible electroluminescent devices

Abstract

Transparent conductive films composed of CuS were formed by wet deposition on PET at room temperature followed by annealing at 100 °C for 1 hour. The resistance of the films was tuned by doping with In³⁺. A decrease of over an order of magnitude of the sheet resistance was obtained, from 1721 Ω sq⁻¹ for undoped CuS film to 109 Ω sq⁻¹ for In³⁺ doped. Transparency of the conducting films could be tuned by an appropriate selection of reaction time and In³⁺ concentration. It was found that films containing 10 mol% of In³⁺ ions after a reaction duration of 24 hours have a sheet resistance of ∼270 Ω sq⁻¹ and a transparency of ∼80%. The fabricated films are characterized by excellent adhesion to the PET substrate and are shown to be suitable for use as transparent conducting electrodes (TCE) in flexible electroluminescent (EL) devices.