Novel TiO₂ hollow Archimedean polyhedrons for self-powered ultraviolet photodetectors enabling encrypted communication and high-fidelity imaging

With the growing demand for miniaturized, low-power optoelectronic system, the low-cost, multifunctional self-powered ultraviolet photodetectors (UVPDs) have garnered widespread research attention. In this work, to obtain suitable materials for constructing high-performance self-powered UVPDs, well-defined and large-scale TiO₂ hollow Archimedean polyhedrons (HAPs) are prepared via a simple solution method through the Cu₂O APs template at a relatively low temperature. The as-prepared TiO₂ HAPs possess unique structural characteristics, including fourteen facets and a rough surface composed of numerous nanoparticles, leading to a specific surface area reaching 60.57 m² g⁻¹. A series of controlled experiments are carried out to thoroughly clarify the formation mechanism of the TiO₂ HAPs. In addition, without external bias, the UVPD constructed with the TiO₂ HAPs exhibits outstanding photoresponse behavior over a wide light intensities range. The device shows fast rise/decay time of below 221/252 ms, together with remarkable operational stability, reflected by only a 1.1% photocurrent variation after 200 on/off cycles and a nearly unchanged photoresponse characteristic under long-term UV irradiation. Moreover, benefiting from the self-powered performance and stable photodetection ability, the TiO₂ HAPs UVPD is applicable for building UV imaging and encrypted communication systems, demonstrating the capability of realizing high-precision imaging and secure information transmission.