Bio-inspired transparent MXene electrodes for flexible UV photodetectors

摘要： As a sort of rising two dimensional materials, MXenes have huge potential for they not only possess superb electrical conductivity and high hydrophilicity, but also enjoy mechanical strength and flexibility. Yet their applications to optoelectronics as electrodes are limited owing to the tradeoff between high transmittance and low conductive resistance, as a low resistance needs more conductive materials, reducing transmission by producing a larger surface coverage. To tackle this bottleneck, here a novel bio-inspired strategy is reported to acquire transparent flexible electrodes with both high transparency and high conductivity which outperform other transparent electrodes. It simultaneously exhibits reliable flexibility during a series of mechanical tests. All these properties of MXene electrodes result from well-designed hierarchical leaf vein network structure and strong adhesion between MXene and urea-treated substrates. In applications, a free-standing semi-transparent UV photodetector is constructed using the MXene electrodes, showing high-performance UV detection as well as superb flexibility and stability. The method provides a new route for MXene based optoelectronics.