Nanostructured Wide Bandgap Semiconductors (NWBS) are supposed to be one of the candidate materials for manufacturing ultraviolet photodetectors (UVPDs) with excellent performance. Recently, different nanostructured ZnO was applied in UVPDs, which has been reported to possess outstanding advantages for UV detection and attract extensive research. Although some significant progress has been reported in the research of UVPDs, there are still other problems needs to be drawn more attention. For example, the electron depletion layer will be caused by the oxygen adsorption on the surface of ZnO, which could reduce the electron concentration. This review begins with machining methods of different nanostructured ZnO (e.g. ZnO nanowires (NWs), nanorods (NRs), microtubes, nanoparticles (NPs), nanoneedles and film) and then the detection mechanism of the UVPDs is also introduced. In addition, UVPDs assembled with core structure mentioned show different photoelectric properties in this review, mainly including responsivity, on/off ratio, and response time. Finally, the development trend of UVPDs research and its application prospect are prospected.

A self-powered photodetector (PD) based on n-type ZnO/p-type small-molecule copper(II) phthalocyanine (CuPc) inorganic/organic heterojunction film deposited on FTO substrate was constructed by simple solution spin-coating and thermal evaporation technology. The designed heterojunction device exhibits typical photoresponse behavior under zero bias, indicating that the device possesses a self-powered characteristic. This may benefit from the formation of a built-in electric field in the heterojunction, which can effectively separate electron–hole pairs. Specifically, the optimal performances of the device appear at a wavelength of 365 nm and light intensity of 0.03 mW cm⁻², achieving on/off ratio of ∼245.88 (29.88), responsivity (R_p) of ∼227.11 mA W⁻¹ (0.39 mA W⁻¹), detectivity (D*) of ∼7.63 × 10¹¹ Jones (∼7.53 × 10⁹ Jones) and EQE of ∼77.23% (0.14%) at +2 V (0 V) bias voltage. In addition, the device has potential application in weak light detection. Therefore, the construction of inorganic/organic heterojunctions may provide a feasible strategy for the development of high-performance, self-powered and wavelength-selective PDs.

The surface plasmon resonance of copper in the near infrared region provides a novel method for enhancement of up-conversion luminescence compared to using gold and silver, as the former grants significant cost savings. In this study, we made a flat Cu film covered TiO₂ to enhance the up-conversion fluorescence intensity. The results show that the deposition of copper/TiO₂ dioxide nanocomposite film prepared via spin-coating has no effect on the structure of NaGdF₄:Er³⁺, Yb³⁺. The absorption wavelength of the copper film moved from the original visible wavelength (~600 nm) range to the infrared wavelength after covering TiO₂, and most obviously, the copper film covered two layers of TiO₂ by about 16 nm; the peak of the absorption appeared at 835 nm due to the enhanced excitation field. The behavior of the nanocomposite film with NaGdF₄:Er³⁺ and Yb³⁺ under 980 nm excitation was investigated; it provides a novel way for studying mental-enhanced fluorescence. Besides, the peaks of the fluorescence spectrum show different emissions at 542 nm and 660 nm, respectively. The copper nanoparticles-covered TiO₂ layer can obviously enhance the fluorescence intensity, and the maximum enhancement factors of emission of NaGdF₄:Er³⁺ and Yb³⁺ nanoparticles are 3.1 and 1.9 on the nanocomposite film, respectively.

The optimized metal-semiconductor-metal (MSM) ultraviolet photodetector (UVPD) based on ZnO/MXene/ZnO (ZMZ) sandwich structure is reported here. Since introducing ZMZ, the photoelectric performance of the UVPD has increased, which benefited from the cooperation between the interface electron depletion layer and injection of hot electrons (HEs), triggering the “storage and ejection” behavior of electrons. In general, under 365-nm laser illumination (6.25 mW/cm $^{\text{2}}$ ), the Responsivity ( $\textit{R}_{\textit{p}}$ ) and Detectivity ( $\textit{D}^{\ast}$ ) are almost unexpectedly increased by approximately an order of magnitude compared with pristine ZnO-based UVPD. More specifically, the ON/OFF ratio, $\textit{R}_{\textit{p}}$ , and $\textit{D}^{\ast}$ are about $>$ 10 $^{\text{3}}$ , 25.48 mA/W, and $>$ 10 $^{\text{11}}$ Jones, respectively. Further, the long-term stable performance of the flexible ZMZ-based UVPD can also be observed after the 1000th bending cycle. And especially, the maximum attenuation coefficient (AC) of photocurrent is only $\sim$ 5.75%. This work may offer a meaningful strategy for designing and improving the performance of ZnO-based UVPD in the future.