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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]

Currently, bismuth oxychalcogenide family (Bi 2 O 2 X, X S, Se, Te), led by Bi 2 O 2 Se with unique characteristics, have emerged as promising candidates for high-performance optoelectronic devices. Herein, the novel Bi 2 O 2 S flowers with hierarchical structure have been successfully prepared via a facile hydrothermal method with only 3 h of reaction. The as-prepared Bi 2 O 2 S flower is composed of many ultrathin nanosheets (NSs) with a thickness of about 12–16 nm. And the possible formation mechanism of ultrathin NSs self-assembled Bi 2 O 2 S flowers is further analyzed. In addition, a self-powered infrared photodetector based on Bi 2 O 2 S flowers, which can work without an external power, is designed. Under illumination at 850 nm light, the Bi 2 O 2 S flowers photodetector exhibits well photoresponse switching behaviors, of which the high responsivity, specific detectivity and fast response time reach up to 9.48 mA/W, 9.96 × 1010 Jones and 227.7 ms, respectively. Of particular note, the Bi 2 O 2 S flowers photodetector also possesses the eximious stability. [Display omitted] ● The Bi 2 O 2 S flowers composed of 2D ultrathin nanosheets were prepared on the fluorine-doped tin oxide substrate. ● The Bi 2 O 2 S flowers infrared photodetector exhibits a high responsivity of 9.48 mA/W and detectivity of 9.96 × 1010 Jones. ● The Bi 2 O 2 S flowers infrared photodetector possesses eximious stability, and can operated without an external power source. [ABSTRACT FROM AUTHOR]

By adopting the alkali metal sodium ion (Na+) doping strategy, the grain size of Cs 3 Bi 2 I 9 (CBI) thin film is significantly increased and the non-radiative recombination defects are effectively passivated. Therefore, the self-powered broadband detection performance of photoelectrochemical detector based on the high-quality CBIN x thin films is greatly enhanced. [Display omitted] • Defect passivated lead-free Cs 3 Bi 2 I 9 polycrystalline perovskite thin film was prepared by alkali metal sodium cation doping. • A simple self-powered broadband photoelectrochemical detector based on Cs 3 Bi 2 I 9 thin film was fabricated. • The detector exhibits excellent photodetection performance without bias at UV, visible and near-infrared region. All-inorganic lead-free bismuth-based perovskites have attracted great interest in the optoelectronic applications due to their low toxicity and excellent stability. However, the inherent polycrystalline (PC) of perovskite films suffers severe charge recombination due to the large numbers of trap density. Herein, high-quality Cs 3 Bi 2 I 9 (CBI) PC thin films are prepared by solution process with alkali sodium (Na+) cation doping strategy, resulting large grain size and lower trap density. Afterward, the photoelectrochemical-type detectors based on Na+ doped CBI thin film is constructed for the first time. The photodetector displays a broadband photoresponse covering ultraviolet (UV), visible and near-infrared (NIR) ranges. Significantly, by precisely controlling Na+ doping concentration, the performance of photodetector can be largely enhanced with the highest responsivity of 53.38 mA/W and detectivity of 5.99 × 109 Jones without bias, and these results exceed the performance of most reported CBI PC thin film based photodetectors. In addition, the photodetector exhibits an obvious increase in photoresponse and outstanding photo-stability after more than 150 on/off cycles. Finally, the mechanism of Na+ doping is further discussed. These results provide an outstanding example for the preparing high-quality CBI PC thin film and also demonstrate the great potential of CBI in the application of self-powered broadband photodetectors. [ABSTRACT FROM AUTHOR]

• Scaly-like hollow SnSe nanotubes (NTs) were synthesized by a green and rapid solution method. • Light utilization efficiency is improved due to unique scaly-like hollow structure and large surface area of the SnSe NTs. • SnSe NTs infrared photodetector can realize efficient and stable IR light detection free of the external power. [Display omitted] SnSe nanotubes (NTs) have been successfully synthesized via a simple solution method. The as-synthesized tubular crystals with orthorhombic structure are composed of numerous scaly nanosheets which distributed hierarchically. The average diameter of the SnSe NTs is roughly 180 nm and length primarily concentrate in the range of 1–3 µm. It was found that Se nanowires were served as a template and as an only source of Se ion for the formation of SnSe NTs. Furthermore, a novel self-powered infrared photodetector (IRPD) established on the SnSe NTs with desirable detection performance was fabricated. Exposed to IR illumination of 830 nm, the SnSe NTs IRPD displays a maximal photocurrent density of 46.46 nA/cm2 and a rapid photoresponse, together with the rise time and decay time approach up to 0.174 s and 0.349 s, respectively. Meanwhile, it can be recognized that the SnSe NTs IRPD remain consistent and repeatable at zero voltage. Moreover, a plausible mechanism for IR detection based on the SnSe NTs IRPD are also discussed. [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]

• 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]