Dual-functionality for solar hydrogen generation and high-performance energy storage

Cadmium zinc telluride (CdZnTe) thin films were successfully synthesized via a cost-effective electrochemical deposition method and characterized for structural, optical, and electrochemical properties to assess their potential for multifunctional applications. X-ray diffraction confirmed the films' polycrystalline nature, and scanning electron microscopy revealed a porous nanorod morphology. Optical studies have shown strong absorption in the visible region and a bandgap of 1.95 eV, making it suitable for optoelectronic applications. Electrochemical analyses, including impedance spectroscopy, galvanostatic charge-discharge, and photoelectrochemical tests, demonstrated the dual functionality of the CdZnTe films in the PEC cell. The electrode exhibited a low charge-transfer resistance of 29.9 Ω, a high specific capacitance of 178 F g-1, an energy density of 15.48 Wh kg -1 , and a power density of 4.98×10 3 W kg -1 , indicating excellent energy storage capabilities. Furthermore, photoelectrochemical measurements revealed a photocurrent density of 3.50 mA cm -2 and an applied-bias photon-to-current efficiency (ABPE) of 1.8% under simulated solar light, highlighting its potential for solar hydrogen generation. The incorporation of Zn into the CdTe lattice enhanced the structural and functional properties of the films compared to pure CdTe films. These findings underscore the promise of electrochemically deposited CdZnTe thin films as efficient and cost-effective materials for integrated energy storage and solar energy conversion.