Flexible In2O3 thin film with columnar structure for enhanced bending durability

Flexible electronics hold significant potential for applications in wearable devices, flexible displays, and biomedicine; however, the brittleness of traditional conductive materials limits their use in flexible devices. In this study, flexible In₂O₃ thin films were fabricated using magnetron sputtering, and their microstructure, electrical properties, interfacial adhesion, and dynamic bending durability were examined. The results show that the In₂O₃ film consists of highly aligned columns oriented along the (400) and (222) crystal planes, providing strong mechanical stability during bending tests. The resistivity decreases with repeated bending and reaches 0.525 Ω cm after 500 cycles, accompanied by a slight reduction in the Seebeck coefficient, indicating self-optimizing behavior. The excellent interfacial adhesion and bending resistance are also attributed to the strong bonding between the columnar In₂O₃ thin film and the flexible substrate, with an adhesion force of 1444.2 mN. This results from the synergistic effect of nanoscale mechanical interlocking from the columnar structure and chemical bonding between oxygen vacancies in the In₂O₃ film and substrate molecules. This study offers both theoretical and experimental support for high-performance flexible electrodes, with promising applications in wearable electronics and flexible thermoelectric conversion.