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Self-powered full-spectrum photodetectors (PDs) offer numerous advantages, such as broad application fields, high precision, efficiency, and multi-functionality, which represent a highly promising and potentially valuable class of detectors for future development. However, insensitive response to solar-blind ultraviolet (UV) and complex and expensive preparation processes greatly limit their performance and practical application. In this study, a self-powered full-spectrum Bi2Se3/a-Ga2O3/p-Si heterojunction PD with high sensitivity for solar-blind UV band prepared by a simple and low-cost two-step synthesis method is presented. Experiments results reveal that the developed PD has an excellent performance, such as high sensitivity from 200 to 850 nm, and a responsivity of 1.38 mA/W as well as a detectivity of 3.22 × 1010 Jones under 254 nm light at zero bias. Additionally, the unencapsulated device displays exceptional stability and imaging capabilities. It is expected that Bi2Se3/a-Ga2O3/p-Si heterojunction PD with a simple and low-cost synthesis method has great potential for self-powered full-spectrum photodetectors. [ABSTRACT FROM AUTHOR]

Films with excellent flexibility and mechanical stability are important for flexible and wearable devices. However, most films reported are prepared on substrates, and the synthesis of freestanding flexible films remains a challenge. Herein, a freestanding Bi2S3 nanofibrous membrane (NFM) is successfully prepared via a one‐step hydrothermal method, which is self‐assembled from ultralong Bi2S3 nanowires (NWs) over a length of millimeter‐scale crisscrossing each other. Significantly, the Bi2S3 NFM can be bent or clipped into an arbitrarily desired form. Based on the freestanding Bi2S3 NFM, an IR photodetector is fabricated, depicting a robust responsivity of 2.23 (2.06) µA W−1 under 850 (940) nm illumination. The Bi2S3 NFM photodetector exhibits a relatively fast response time (47.1 ms), which is attributed to high‐speed carrier transport efficiency in the NWs network. Under the bending states, the device still exhibits excellent detection performance, maintaining more than 86% of the initial photocurrent even after 1000 bending‐flattening times. The robust photoresponse of the Bi2S3 NFM photodetector after 2 months of storage in air and after 1 week in the bending state illustrates its excellent air stability and flexible detection ability. Besides, the photodetector can clearly identify the target image, indicating widespread potential applications in flexible and wearable fields. [ABSTRACT FROM AUTHOR]

[Display omitted] • Large-scale Bi 2 O 3 /Ag/TiO 2 nanotubes (BAT NTs) were successfully synthesized through the facile solution process at room temperature. • BAT NTs ultraviolet photodetector (UVPD) exhibits satisfactory photodetection performance with a fast response speed of 25 ms. • BAT NTs UVPD features excellent environmental stability after 1 month and cycling stability for 100 switching cycles. • BAT NTs UVPD achieves high-resolution imaging results with "UV" pattern and performs precise UV optical communication under zero bias. Large-scale Bi 2 O 3 /Ag/TiO 2 nanotubes (BAT NTs) were successfully synthesized using ZnO nanorods template through the facile solution process at room temperature. Highly ordered BAT NTs with an average diameter of approximately 300 nm were arranged hierarchically on the overall ITO substrate. In addition, a self-powered UV photodetector (UVPD) based on BAT NTs was assembled and the photoresponse characteristics were investigated under a wide range of UV light intensity. The BAT NTs UVPD exhibits satisfactory UV photodetection performance with detectivity of 1.55 × 1010 Jones and on/off ratio exceeding 103, associated with a fast response speed of 25 ms, which is ascribed to the efficient carrier transport inspired by the 1D structure and energy band structure. In addition, BAT NTs UVPD also features excellent environmental stability and long cycling stability. Benefitting from the desirable properties, the BAT NTs UVPD achieves high-resolution imaging results with "UV" pattern as a single pixel unit and performs accurate UV optical communication as a signal receiver at zero bias. Eventually, the detailed self-powered UV detection mechanism for BAT NTs UVPD was illustrated. [ABSTRACT FROM AUTHOR]

Homogeneous and large-scale Bi 2 O 3 nanospheres (NSs) were successfully prepared using a one-step hydrothermal route. It is noticed that the Bi 2 O 3 NSs were dominated by the spherical shape covered by convex bulges, where the average diameter ranged from 100 to 200 nm. After that, the Bi 2 O 3 NSs were used to fabricate the ultraviolet photodetector (UVPD) with self-powered feature. After being illuminated with UV light of 365 nm, the response time of the Bi 2 O 3 NSs UVPD can reach up to ∼26 ms, and the detectivity achieved 1.77 × 109 Jones, associated with on/off ratio of more than 103. The temporal stability after storage in air for 1 month and the long cycle stability of 100 cycles both confirmed the robust stability of Bi 2 O 3 NSs, and the photocurrent can still reach 98.5% of the initial value for 100 cycles. Moreover, high-resolution image with Chinese characters of "Ha Gong Da" was well acquired under 365 nm light irradiation, which confirmed the fast light extraction capability and high dynamic range of the device. Furthermore, the detection mechanism of the Bi 2 O 3 NSs UVPD was also discussed. • Large-scale convex Bi 2 O 3 nanospheres (NSs) were synthesized adopting a facile one-step synthesis strategy. • Bi 2 O 3 NSs ultraviolet photodetector (UVPD) displays fast response time and large on/off ratio at zero bias under UV light. • Bi 2 O 3 NSs UVPD features robust temporal stability after 1 month and long cycle stability for 100 cycles. • Bi 2 O 3 NSs UVPD can achieve high-resolution images and exhibit fast light extraction capability and high dynamic range. [ABSTRACT FROM AUTHOR]

[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]

Massive two-dimensional (2D) Bi 2 O 3 nanosheets (NSs) were synthesized adopting a facile solution route. It can be distinctly perceived that the average dimension of the Bi 2 O 3 NSs was mainly centered in the range of 1–2 μm and the thickness reached about 110 nm. Afterward, the self-powered ultraviolet photodetector (UVPD) was successfully prepared established on the 2D Bi 2 O 3 NSs, which exhibited high photosensitivity and robust stability in exposure to UV light, accompanied with the fast rise time of ∼33 ms and decay time of ∼47 ms. In addition, the Bi 2 O 3 NSs UVPD could perform a stable operation over a wide range of UV light intensities. Moreover, the photodetection mechanism for the Bi 2 O 3 NSs UVPD was also illustrated. • Massive two-dimensional Bi 2 O 3 nanosheets were synthesized adopting a facile solution route. • Exposure to UV light, Bi 2 O 3 nanosheets UV photodetector exhibited high photosensitivity free of the external power. • Bi 2 O 3 nanosheets UV photodetector could perform stable operation over the wide range of UV light intensities. [ABSTRACT FROM AUTHOR]

[Display omitted] • Large-scale Bi 2 O 3 nanotubes (NTs) arrays were successfully synthesized on ITO substrate employing ZnO nanorods. • An ultraviolet photodetector based on Bi 2 O 3 NTs was fabricated to show fast response speed and good cycling stability. • Bi 2 O 3 NTs ultraviolet photodetector could realize accurate UV detection free of external power. Large-scale Bi 2 O 3 nanotubes (NTs) arrays were successfully synthesized on ITO substrate with the assistance of ZnO nanorods template at room temperature. The as-synthesized highly orientated Bi 2 O 3 NTs with an average diameter of ∼95 nm were well distributed throughout the entire substrate. Moreover, Bi 2 O 3 NTs were employed to construct the ultraviolet photodetector (UVPD). Received to UV irradiation, the Bi 2 O 3 NTs UVPD displayed a high average current density of 40.4 μA/cm2, coupled with fast average rise time of ∼28.8 ms and decay time of ∼40.9 ms. Furthermore, the Bi 2 O 3 NTs UVPD could carry out accurate UV detection without external bias as well as maintain good stability and repeatability. Additionally, the UV detection mechanism of the as-assembled Bi 2 O 3 NTs UVPD was also discussed. [ABSTRACT FROM AUTHOR]

Large-area octahedral Bi 2 O 3 nanoblocks (NBs) have been successfully fabricated on ITO substrate through a facile hydrothermal synthesis. The Bi 2 O 3 NBs with an average diameter of ∼2 μm were homogeneously grown over the entire surface of the substrate. Furthermore, the ultraviolet photodetector (UVPD) was assembled based on the Bi 2 O 3 NBs. On exposure to UV light, the photocurrent density of Bi 2 O 3 NBs UVPD surged to 38.5 μA/cm2, associated with rapid rise and decay time of ∼27.7 ms and ∼27.2 ms respectively. Especially, the as-fabricated detector could achieve stable UV detection free of the power supply and exhibit good stability and reusability. Moreover, the growth mechanism of the Bi 2 O 3 NBs and detection mechanism of the Bi 2 O 3 NBs UVPD have been investigated. [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]

Films with honeycomb‐like structures have became ideal network structures for the development of flexible photodetectors due to their superior mechanical stability and merits in large active surface area, high carrier transport efficiency and well light absorption capacity. In this work, a honeycomb‐like Bi2S3 film with centimeter‐scale (2 cm × 2 cm) is synthesized on an ultrathin flexible fluorophlogopite mica substrate, which consists of a well‐stabilized arrangement of triangular unit structures forming an interconnected network structure. Based on the as‐grown honeycomb‐like Bi2S3 film, a flexible photodetector with a broadband response from ultraviolet to infrared is constructed, which displays the highest responsivity (Rλ) of 611.2 mA W−1 and specific detectivity (D*) of 4.77 × 1010 Jones. And at 850 nm light illumination, there is nearly no deterioration in Rλ and D* of the Bi2S3 flexible photodetector after successive multiple bends, benefiting from the excellent structural stability of the triangular honeycomb network structure. Notably, the device maintains excellent detection performance after 1 week of prolonged bending in air without any encapsulation, and its photocurrent can still reach 90.39% of the initial photocurrent. In addition, the device also exhibits favorable durability, cycle stability, as well as high‐definition imaging ability in bending state and after bending recovery. [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]

A novel hedgehog-like ZnO/SnO 2 hierarchical heterostructures composing of one-dimensional ZnO nanorods (NRs) and three-dimensional SnO 2 octahedron nano-blocks (ONBs) have been successfully prepared on ITO substrate through a simple solution method. The results show that ZnO NRs are uniformly and densely distributed perpendicular to the surface of the SnO 2 ONB. The as-prepared ZnO NRs/SnO 2 ONB (Z/S) hierarchical heterostructure is applied to assemble ultraviolet photodetector (UVPD). Under UV light illumination, it can obviously find that the Z/S UVPD can work at zero bias voltage and exhibits a remarkable stability and repeatability. In addition, the Z/S UVPD displays excellent characteristics over that based on SnO 2 ONBs, in particular a relatively high photoresponsivity, a strong photocurrent density of 0.94 mA cm−2, together with a high on/off ratio of 5362. Moreover, the possible mechanisms for growth and UV detection on the hedgehog-like Z/S hierarchical heterostructure have been discussed. [ABSTRACT FROM AUTHOR]