Fabrication of transparent conducting composite films using surface-embedded metal nanostructured materials on glass-fabric reinforced hybrid film for optoelectronic devices

Abstract

Transparent conducting composite films are fabricated using surface-embedded metal nanostructured materials on glass-fabric reinforced hybrid film, and their applicability for flexible optoelectronic devices are demonstrated. The metal nanostructured materials such as metal nanowire (NW) and metal networks are the promising transparent conducting electrode (TCE) materials for future flexible optoelectronic devices. The glass-fabric reinforced hybrid film (GFRHybrimer) is a high-performance composite film, which consists of sol-gel derived organic-inorganic siloxane hybrid material as a matrix and glass cloths as a reinforcement. By combining the metal nanostructured TCE materials and the GFRHybrimer film, several advantages are obtained such as enhanced stabilities and smoothened surface roughness. First, metal NW-GFRHybrimer films (AgNW-, and CuNW-GFRHybrimer) are fabricated by embedding the metal NW (Ag and CuNW) onto the GFRHybrimer films. The metal NW-GFRHybrimer films exhibit smooth surface topography ($R_{rms}$ < 2 nm), improved thermal/chemical stability, mechanical robustness, and excellent opto-electrical performances. To demonstrate their potential as flexible metal NW TCE platform, flexible organic photovoltaic devices (OPV) and flexible organic light emitting diode devices (OLED) are fabricated on the AgNW- and CuNW-GFRHybrimer films, respectively. The flexible OPV on the AgNW-GFRHybrimer film shows power conversion efficiency (PCE) of 5.9% under $100 mW cm^{-2}$ under 1.5G illumination. The flexible OLED on the CuNW-GFRHybrimer film operates stably under flexed state. Also, I propose crystalline indium tin oxide/metal nanowire composite electrode (c-ITO/metal NW-GFRHybrimer) films as a robust platform for flexible optoelectronic device applications. Very thin c-ITO is introduced as an over-coating layer to surface-embedded metal NW networks. The c-ITO/metal NW-GFRHybrimer films exhibit outstanding mechanical flexibility, excellent opto-electrical property, and thermal/chemical robustness. Highly flexible and efficient metal halide perovskite solar cell devices are fabricated on the films. The devices on the c-ITO/AgNW- and c-ITO/CuNW-GFRHybrimer films exhibit PCE values of 10.16% and 9.33%, respectively. Lastly, I propose metal nanotrough-embedded transparent conducting hybrid film (metal nanotrough-GFRHybrimer). Using electro-spun polymer nanofiber web as a template and vacuum-deposited gold as a conductor, a junction resistance-free continuous metal nanotrough network is formed. Subsequently, the metal nanotrough is embedded in the GFRHybrimer film. The monolithic composite structure of the metal nanotrough-GFRHybrimer film allows simultaneously high thermal stability, a smooth surface topography ( $R_{rms}$ < 1 nm) and an excellent opto-electrical property. A flexible touch screen panel (TSP) is fabricated using the transparent conducting films. The flexible TSP device stably operates on the back of a human hand and on a wristband.