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[Display omitted] • Large-area Bi 2 O 2 Se film composed of many single crystal nanosheets was synthesized. • The layered Bi 2 O 2 Se film features a sharp interface with the SrTiO 3 substrate. • Bi 2 O 2 Se photodetector exhibits excellent cycling stability and long-term stability. • Bi 2 O 2 Se photodetector displays good imaging capability and rapid light extraction. Two-dimensional (2D) materials have proven to be a highly promising candidate for applications in electronic and optoelectronic devices due to their attractive structure and properties. However, the micron-scale dimensions, random distribution on the substrate, and complex transfer processes of 2D materials inevitably cause difficulties in device integration, which limits practical applications in photodetection. Herein, high-quality 2D Bi 2 O 2 Se film (2×2 cm) composed of numerous single crystal nanosheets on SrTiO 3 substrate was prepared employing the chemical vapor deposition method. The layered Bi 2 O 2 Se film features a perfect atomic alignment free of lattice mismatch and a sharp interface with the SrTiO 3 substrate. Afterward, a broadband photodetector based on 2D Bi 2 O 2 Se film was directly constructed, which covered the ultraviolet, visible and infrared range from 365 to 940 nm and demonstrated a fast response speed of 32 ms and 44 ms, maximum responsivity and detectivity of 136 mA/W and 2×109 Jones. Importantly, fast on/off behavior for 100 cycles and reliable photoresponse after storage in air for 1 year confirmed the excellent cycling stability and air stability of the Bi 2 O 2 Se photodetector. Furthermore, the Bi 2 O 2 Se photodetector as a single point sensing pixel was capable to perform high-resolution imaging of "H, I, T" patterns. This research affirms the huge potential of Bi 2 O 2 Se photodetectors to perform as reliable multi-band detection units in complex systems. [ABSTRACT FROM AUTHOR]

Traditional photoelectrochemical-type (PEC-type) photodetectors have encountered several obstacles in practical application, such as the loss of photoelectrons due to interface charge recombination, short-term performance, and the problem of liquid electrolyte leakage. Herein, a novel quasi-solid-state polysulfide gel electrolyte (QSSPGE) is developed through the integration of liquid polysulfide into the polyvinyl alcohol (PVA) gel matrix. The PVA gel plays the dual function of passivating the surface trap states of bismuth telluride (Bi 2 Te 3) nanosheets and suppressing the leakage and volatilization of the liquid polysulfide electrolyte. Impressively, the PEC-type Bi 2 Te 3 photodetector based on the QSSPGE exhibits a boosted responsivity of 4.91 mA W−1 and a fast rise/decay time of 14/99 ms under 365 nm illumination, outperforming the responsivity (4.32 mA W−1) of PEC-type Bi 2 Te 3 photodetector based on liquid polysulfide. More importantly, the photocurrent density of the device remains at 95% and 81% of the initial value after being stored in air for one month and heated at 80 ℃ for 240 min, respectively, demonstrating excellent long-term stability and thermal stability. Additionally, the high-resolution imaging capacity of the device is demonstrated. This work provides an effective strategy for fabricating high-performance, stable PEC-type optoelectronic devices. [Display omitted] • A novel quasi-solid-state polysulfide gel electrolyte (QSSPGE) is developed. • Interface charge recombination between Bi 2 Te 3 and QSSPGE is suppressed. • Responsivity of the device is boosted from 4.32 mA W−1 to 4.91 mA W−1. • The device based on QSSPGE exhibits excellent thermal and long-term stability. • The stable imaging capacity of the device is demonstrated. [ABSTRACT FROM AUTHOR]

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]

All-inorganic metal halide perovskite is considered as one of the most promising perovskite materials for photodetectors, because of its remarkable optoelectronic characteristics and stability. Whereas, it remains challenge to achieve both excellent photodetection performance and stability due to the multitudes of defects in perovskite films. Herein, an interface engineering based on surface passivation strategy to achieve high-quality CsPbBr 3 perovskite films by introducing thioacetamide (C 2 H 5 NS, abbreviated as TAA) as interface materials is reported. The interaction between TAA and perovskite passivates the uncoordinated Pb2+ on the surface of CsPbBr 3 film, suppress carrier non-recombination and accelerates carriers transfer. The self-powered photodetector based on the passivated CsPbBr 3 film prefers the maximum responsivity of 0.26 A W−1 and detectivity of 8.39 × 1012 Jones under 520 nm irradiation. In addition, the optimized photodetector exhibits excellent stability and maintains more than 98% of its initial photocurrent when operating over 8 h. This work demonstrates an alternative approach for the preparation of improved performance in CsPbBr 3 perovskite photodetectors and associated photoelectric devices. [Display omitted] • Introducing thioacetamide into the perovskite device as interface layer. • The device is self-powered, high-detectivity and rapidly detection to radiation. • The device achieved a champion responsivity of 0.26 A/W with excellent stability. [ABSTRACT FROM AUTHOR]