Self‐Cleaning Ultraviolet Photodetectors Based on Tree Crown‐Like Microtube Structure

Abstract Photodetectors are extensively applied in a wide range of applications. In particular, hierarchical ZnO micro/nanostructure has achieved promising success in the fields of advanced photodetectors. By utilizing hierarchical structure, development of functional photodetectors with self‐cleaning properties would extend the applications of photodetectors in more severe environments. Recent reports have demonstrated the advantages of nanofabricated surfaces with re‐entrant geometry to obtain superoleophobicity that can repel low surface tension liquids such as biofluids or oils. Inspired by the excellent liquid repellency of re‐entrant geometry, here a self‐cleaning ultraviolet photodetector is reported based on tree crown‐like microtube (TCLMT) structure. The TCLMT consisted of a ZnO microtube‐trunk structure branched with numerous ZnO nanospikes on top, presenting a re‐entrant geometry that effectively repelled water and various biological fluids. The TCLMT is fabricated using a microporous membrane‐templated method, followed by multiple steps of material deposition, plasma etching, and hydrothermal growth. The fluorinated ZnO TCLMT‐based photodetector exhibits excellent photoelectric performance as well as resistance against biofouling solution such as bacterial suspension. This work provides a versatile approach to achieve controlled fabrication of re‐entrant structures with excellent liquid repellent properties as well as extending ZnO‐based photodetectors to be self‐cleaning and resistant to biofouling.