Structural, optical, and electrical properties of Ag-doped CuO thin films deposited on flexible polyimide substrates via chemical spray pyrolysis

This study reports the successful fabrication of undoped and Ag-doped copper oxide (Ag-doped CuO) thin films on flexible polyimide (PI) substrates using chemical spray pyrolysis. The research investigates the impact of different Ag-doping concentrations (0%, 1%, and 3%) on the structural, optical, and electrical characteristics of the films. Structural analysis via X-ray diffraction confirmed a monoclinic tenorite phase, with enhanced crystallinity and an increased crystallite size from 50.1 nm to 79.4 nm upon 3% Ag doping. Optical measurements revealed that silver incorporation broadens the energy band gap from 1.94 eV to 2.28 eV, while maintaining high optical transparency reaching ~95% in the visible region. Furthermore, electrical characterization showed a substantial decrease in resistivity from 45.30 to 7.98 Ω.cm, driven by a twofold increase in Hall mobility. These results demonstrate that Ag-doping optimizes charge transport, positioning these flexible films as efficient candidates for transparent conducting electrode applications in next-generation flexible optoelectronics.