Versatile Solution-Processed Organic–Inorganic Hybrid Superlattices for Ultraflexible and Transparent High-Performance Optoelectronic Devices

Crystalline or amorphous metal oxides are widely used in various optoelectronic devices as key components, such as transparent conductive electrodes, dielectrics or semiconducting active layers for thin-film transistor (TFT) backplanes in large-area displays, photovoltaics, and light-emitting diodes. Although crystalline inorganic materials demonstrate outstanding optoelectronic performance, owing to their wide band-gaps, large conductivities, and high carrier mobilities, their inherent brittleness makes them vulnerable to mechanical stress, thereby limiting the use of metal oxide films in emerging flexible electronic applications. In this study, we developed stress-diffusive organic–inorganic hybrid superlattice nanostructures to overcome the mechanical limitation of crystalline oxides and to provide high mechanical stability to metal oxide semiconductors. Particularly, hybrid transparent superlattice electrodes based on crystalline indium tin oxide exhibit high electrical conductivities of up to 555 S cm^-1 (resistance variation <3%) and effectively reduce the mechanical stress on the inorganic layer (up to 10000 bending cycles with a radius of 1 mm). Furthermore, to ensure the viability of the hybrid superlattice flexible electronics, all solution-processed superlattice crystalline indium gallium oxide TFTs are implemented on a thin (~5 mm) polyimide substrate, providing highly robust and excellent electrical performance (average mobility of 7.6 cm²V^-1s^-1).