Laser-patterned tungsten trioxide (WO3) electrochromic devices for smart windows and informative displays with optical and thermal control

Tungsten trioxide (WO 3 ) is a promising electrochromic material owing to its reversible structural and optical modulation under applied voltage. Despite advantages such as rapid switching and electrochemical stability, the functional diversification of electrochromic devices (ECDs) remains limited, largely due to the absence of effective patterning strategies. Here, we present a facile laser ablation approach for precise and controllable patterning of WO 3 thin films, enabling on-demand optical transmittance modulation. The laser-defined patterns can further serve as simple informative display elements, demonstrating localized visual switching based on patterned geometries. The process removes both the WO 3 layer and the underlying fluorine-doped tin oxide (FTO) layer from the glass substrate, as confirmed by UV–vis spectrometry and X-ray diffraction. The influence of patterning density on thermal management performance is further evaluated under infrared irradiation, revealing its potential for heat-shielding functionality in optoelectronic applications.