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The all-inorganic perovskite cesium lead bromine (CsPbBr3) has attracted much attention in the field of X-ray detectors because of its high X-ray absorption coefficient, high carrier collection efficiency, and easy solution preparation. The low-cost anti-solvent method is the main method to prepare CsPbBr3; during this process, solvent volatilization will bring a large number of holes to the film, leading to the increase of defects. Based on the heteroatomic doping strategy, we propose that Pb2+ should be partially replaced by Sr2+ to prepare leadless all-inorganic perovskite. The introduction of Sr2+ promoted the ordered growth of CsPbBr3 in the vertical direction, increased the density and uniformity of the thick film, and achieved the goal of CsPbBr3 thick film repairing. In addition, the prepared CsPbBr3 and CsPbBr3:Sr X-ray detectors were self-powered without external bias, maintaining a stable response during on and off states at different X-ray dose rates. Furthermore, the detector base on 160 µm CsPbBr3:Sr had a sensitivity of 517.02 µC Gyair−1 cm−3 at zero bias under the dose rate of 0.955 µGy ms−1 and it obtained a fast response speed of 0.053–0.148 s. Our work provides a new opportunity to produce cost-effective and highly efficient self-powered perovskite X-ray detectors in a sustainable way. [ABSTRACT FROM AUTHOR]

Highly crystallized ZnO-Ga2O3 core-shell heterostructure microwire is synthesized by a simple one-step chemical vapor deposition method, and constructed into a self-powered solar-blind (200-280 nm) photodetector with a sharp cutoff wavelength at 266 nm. The device shows an ultrahigh responsivity (9.7 mA W−1) at 251 nm with a high UV/visible rejection ratio ( R251 nm/ R400 nm) of 6.9 × 102 under zero bias. The self-powered device has a fast response speed with rise time shorter than 100 µs and decay time of 900 µs, respectively. The ultrahigh responsivity, high UV/visible rejection ratio, and fast response speed make it highly suitable in practical self-powered solar-blind detection. Additinoally, this microstructure heterojunction design method would provide a new approach to realize the high-performance self-powered photodetectors. [ABSTRACT FROM AUTHOR]

Hybrid perovskite materials have been one of the brightest spotlights in the radiation detection research fields due to their higher carrier mobility and lower trap state density in recent years. In this paper, the CsPbBr3 microcrystal thick film is successfully prepared using a low‐cost facile solution synthesis method. The properties of samples are characterized by field‐emission scanning electron microscope (FE‐SEM), X‐ray diffraction (XRD), and UV‐vis diffuse reflectance spectrum (UV‐vis DRS). In addition, X‐ray detectors based on the CsPbBr3 microcrystal thick film are fabricated and the photoelectric properties of the detectors are further improved through the multiple‐times dissolution–recrystallization method. An improved sensitivity of 470 µC Gyair−1 cm−2 is obtained for X‐ray photodetector based on recrystallized CsPbBr3 microcrystal thick film at zero bias under a remarkably low dose rate (0.053 µGyair s−1). This sensitivity is over 20 times higher than that of α‐Se X‐ray detectors working at a much higher field of 10 V µm−1. The current investigation can provide an efficient low‐cost and facile method to fabricate self‐powered X‐ray detectors based on CsPbBr3 microcrystal thick film that work normally at low radiation dose rate. [ABSTRACT FROM AUTHOR]

A self-powered, broad band and ultrafast photodetector based on n + -InGaN/AlN/n-Si(111) heterostructure is demonstrated. Si-doped (n + type) InGaN epilayer was grown by plasma-assisted molecular beam epitaxy on a 100 nm thick AlN template on an n-type Si(111) substrate. The n + -InGaN/AlN/n-Si(111) devices exhibit excellent self-powered photoresponse under UV-visible (300-800 nm) light illumination. The maximum response of this self-powered photodetector is observed at 580 nm for low-intensity irradiance (0.1 mW/cm 2 ), owing to the deep donor states present near the InGaN/AlN interface. It shows a responsivity of 9.64 A/W with rise and fall times of 19.9 and 21.4 μs, respectively. A relation between the open circuit voltage and the responsivity has been realized.

The growing needs in monitoring health and environmental risks call for the development of smart ultraviolet (UV) photodetectors with special or multiple functions. Herein, a photoelectrochemical cell based self‐powered and wearable UV photodetector system with high stability, high speed, and an interesting visualization feature is successfully developed. TiO2 nanotubes on flexible Ti foil and Prussian blue on flexible polyethylene terephthalate/indium‐tin oxide are selected as the photoanode and electrochromic counter electrode, respectively. The integrated flexible UV photodetectors can not only function stably for many bending cycles but also exhibit visualized indication of UV exposure by recyclable color change without external power. Moreover, the as‐fabricated visible‐blind photodetectors show excellent UV responsivity (78.3 mA W−1), ultralow UV light detection limit (<10 µW cm−2), and fast response with a rise time and a decay time of 0.04 and 0.06 s, respectively. Our all‐in‐one smart photodetector has demonstrated great application potential in self‐powered smart sensors and wearable healthcare electronics. An all‐in‐one visualized, self‐powered, and wearable UV photodetector is successfully developed. The self‐powered and wearable photodetector shows excellent UV responsivity, an ultralow detecting limit, and fast response performance. Strikingly, the UV intensity can be visually judged by the degree of decoloration and also provides visualized indication of UV exposure by recyclable color change. [ABSTRACT FROM AUTHOR]

Self-powered flexible photodetectors without an external power source can meet the demands of next-generation portable and wearable nanodevices; however, the performance is far from satisfactory becuase of the limited match of flexible substrates and light-sensitive materials with proper energy levels. Herein, a novel self-powered flexible fiber-shaped photodetector based on double-twisted perovskite-TiO 2 -carbon fiber and CuO-Cu 2 O-Cu wire is designed and fabricated. The device shows an ultrahigh detectivity of 2.15 × 10 13 Jones under the illumination of 800 nm light at zero bias. CuO-Cu 2 O electron block bilayer extends response range of perovskite from 850 to 1050 nm and suppresses dark current down to 10 -11 A. The fast response speed of less than 200 ms is nearly invariable after dozens of cycles of bending at the extremely 90 bending angle, demonstrating excellent flexibility and bending stability. These parameters are comparable and even better than reported flexible and even rigid photodetectors. The present results suggest a promising strategy to design photodetectors with integrated function of self-power, flexibility, and broadband response., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)