Fabrication of electrochromic devices by laser patterning of spin-sprayed transparent conductive Ga:ZnO films

Despite their significant economic benefits, wet processes are rarely adopted in optoelectronics industries because of their inherent difficulties in producing high-quality functional films compared with dry processes. Unlike other conventional wet processes, spin-spraying promotes surficial heteronucleation by continuously providing fresh source ions onto the substrate surface and removing excess ions left after nucleation from the surface. Surficial heteronucleation ensures the formation of high-quality films with dense microstructures that are comparable to those obtained by dry processes. This study describes a novel spin-spraying method for growing Ga-doped ZnO (Ga:ZnO) films on glass substrates. The optimum Ga doping concentration of the spin-sprayed Ga:ZnO (SSedGZO) films was determined from the electrical and optical properties of the films. Further, the feasibility of employing UV laser patterning to produce patterned SSedGZO films for application as transparent electrodes (TEs) in optoelectronic devices was evaluated, and the optimum laser power required for effective patterning was determined by analyzing the surface microstructures of the patterned films. Finally, to confirm the practical applicability of the SSedGZO films as TEs, electrochromic devices (ECDs) comprising the SSedGZO TEs were fabricated. The laser-patterned SSedGZO TEs functioned successfully in the fabricated ECDs, displaying reversible color changes through electrochromic switching.