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The development trend of modern electronics and optoelectronics is constantly moving towards highly integrated, comprehensive, and miniaturized devices. Vertical configuration provides an easy means to achieve higher integration density than traditional planar configuration, and possess higher carrier generation capabilities and transfer speed, which can further enhance the performance of optoelectronic devices. This technology holds tremendous potential for designing the next generation of electronic/optoelectronic devices. In this work, we developed a vertical heterojunction photodetector, which combines narrow-bandgap 2D topological insulator Bi 2 Se 3 , ultra-wide-bandgap amorphous Ga 2 O 3 , and high-performance p-Si substrate, achieving broad-spectrum detection from 254 to 1000 nm and significantly shortened response time due to the advantage of carrier vertical transmission. The response time of the device is less than 50 ms under illumination with different wavelengths. Moreover, the device exhibits self-powered characteristics, with maximum responsivity and detectivity of 0.175 mA/W and 1.58 × 1010 Jones, respectively, under 365 nm light irradiation at zero bias. A switch ratio as high as 10 3 is demonstrated under 365 and 470 nm illumination, highlighting the high performance of device. Additionally, the device displays excellent stability and imaging capability. Our research provides a promising and instructive prospect for the practical application of vertical broadband self-powered heterojunction PDs in a wider range of fields. • A vertical self-powered Bi 2 Se 3 /a-Ga 2 O 3 /p-Si heterojunction PD was achieved. • The device showed broadband response (254–1000 nm) and imaging ability. • Switch ratio as high as 103 under 365 and 470 nm illumination was presented. [ABSTRACT FROM AUTHOR]

• MAPbCl 3 and amorphous Ga 2 O 3 formed a hybrid structure for the first time. • The responsivity enhanced nearly 70 times by inserting the amorphous Ga 2 O 3 layer. • The MAPbCl 3 /amorphous Ga 2 O 3 photodetector is sensitive with high-detectivity. • The performance of polycrystalline detector is comparable to single crystal device. • The detector is self-powered and realizes accurate detection of UVA radiation. [Display omitted] UVA radiation can survive from the absorption of atmospheric layer and reaches the terrestrial surface, which is harmful to human eyes, blood vessels, and elastic fibers. It is meaningful to detect the UVA radiation precisely. A sensitive, high-detectivity and self-powered UVA detector based on polycrystalline CH 3 NH 3 PbCl 3 /amorphous Ga 2 O 3 hybrid structure is presented in this work. Under zero bias, the rise/decay time of the photodetector are 56/67 ms, and the detectivity reaches up to 5.4 × 1010 Jones. The performance is even superior to most of the reported devices based on CH 3 NH 3 PbCl 3 single crystal. The heterojunction between amorphous Ga 2 O 3 and CH 3 NH 3 PbCl 3 accelerates the separation of photon-generated carrier and effectively reduces the recombination. In addition, the high resistivity and low surface roughness of the amorphous Ga 2 O 3 layer also contribute to the improvement of device parameters. This study offers new insights to improve the polycrystalline MAPbCl 3 devices by ultra-wide bandgap amorphous semiconductors. [ABSTRACT FROM AUTHOR]

Photocatalytic water splitting into hydrogen is regarded as one of the key solutions to the deterioration of the global environment and energy. Due to the significantly reduced grain boundaries, ZnO nanorods facilitate a fast electron transfer through their smooth tunnels and are well suited as a photocatalyst. However, the photocatalytic hydrogen evolution performance of pristine ZnO nanorods is still low due to the high recombination rate of photogenerated electron-hole pairs and the less light absorption. Here, a novel structure about black ZnO nanorods (NRs)/TiO2-X mesoporous spheres (MSs) heterojunction has been prepared and the photocatalytic hydrogen evolution performance has been explored. The photocatalytic activity test results showed that ZnO NRs/TiO2-X MSs exhibited higher catalytic activity than ZnO NRs for hydrogen production. Compared to the pure ZnO NRs photoanode, the photocurrent of ZnO NRs/TiO2-X MSs heterojunction photoanode could reach 0.41 mA/cm2 in view of the expanding spectral response region and effective inhibition of e−/h+ recombination at the same condition. Using a relatively integrated experimental investigation and mechanism analysis, we scrutinized that after being treated with NaBH4, TiO2 MSs introduce oxygen vacancies expanding the photocatalytic activity of pure TiO2, and improving conductivity and charge transport capabilities through coating on ZnO NRs. More importantly, the results provide a promising approach in the NRs/MSs composite structure serving as photoanodes for photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]