Electrochromic tungsten oxide (WO₃) films suffer from gradual performance degradation during repeated ion insertion/extraction processes, while the relationship between electrolyte-dependent ion accommodation and structural stability remains insufficiently understood. Herein, magnetron-sputtered WO₃ thin films were systematically investigated in H₂SO₄, LiClO₄, ZnSO₄, and Al₂(SO₄)₃ electrolytes to clarify the coupling relationship among ion accommodation, electronic structure evolution, microstructural retention, and electrochromic durability. Combined electrochemical measurements with UV–visible spectroscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and reflected electron energy loss spectroscopy (REELS) reveal that electrolyte chemistry regulates the balance between electrochemical activation and structural tolerance. Highly mobile H⁺ and strongly interacting Al³⁺ ions promote rapid ion transport and enhanced W⁶⁺ reduction but may induce excessive structural perturbation, defect accumulation, and accelerated degradation during cycling. Zn²⁺ exhibits intermediate behavior, whereas Li⁺ enables balanced ion accommodation through reversible W⁶⁺/W⁵⁺ conversion while preserving the WO₃ framework. Consequently, the LiClO₄ electrolyte achieves superior electrochromic performance with an optical modulation of 80.97% and improved cycling stability. These results demonstrate that durable electrochromic behavior is governed not by maximizing ion transport or reduction degree, but by achieving a reversible ion accommodation regime compatible with the structural tolerance of the host framework. This work provides a microstructure-oriented strategy for designing stable WO₃-based electrochromic devices through electrolyte regulation.

This study investigates the optimization of RF sputtering power for high-performance ITZO TFTs by correlating the film physicochemical properties, oxygen-related defects, and device characteristics. The films were used as the channel layer in thin-film transistors (TFTs). XRD, UV–Vis spectroscopy, and XPS were systematically used to investigate the effects of sputtering power on the film structure, optical properties, chemical composition, and electrical performance of the devices. The results show that X-ray diffraction (XRD) analysis revealed that the ITZO films prepared at different sputtering powers were predominantly amorphous in structure. UV–Vis measurements indicated that the ITZO films maintained a high optical transmittance (>85%), demonstrating their strong potential for application in transparent electronic devices. X-ray photoelectron spectroscopy (XPS) analysis further showed that the sputtering power affected the chemical states of In, Sn, Zn, and O elements, as well as the concentration of oxygen vacancies in the films. Appropriately increasing the sputtering power was found to help regulate the carrier concentration and defect states of the films. When the sputtering power was 70 W, the ITZO TFT exhibited superior electrical performance, with a saturation mobility of 8.46 cm²·V⁻¹·s⁻¹, a threshold voltage of 1.86 V, a subthreshold swing of 0.29 V/decade, and an on/off current ratio of 4.50 × 10⁹.