Search

The detection and monitoring of toxic and harmful gases play a vital role in environmental protection, human health, and industrial and agricultural production. However, it is still challenging to develop gas sensors for the detection of toxic and harmful gases with high sensitivity, good recovery and excellent selectivity. In this study, WO3/Al2O3/graphite composite materials were used for an MEMS 2-CEES gas sensor (dichlorodiethyl sulfide simulation), and the corresponding sensing properties were explored. The experimental results show that when the working temperature is 340 °C, the response of the sensor to 2-CEES gas with a concentration of 5.70 ppm is 69%, the response time is 5 s and the recovery time is 42 s. The sensor also has the advantages of long-term stability and high selectivity. Furthermore, the MEMS gas sensor array based on WO3/Al2O3/graphite composite materials has been achieved and also exhibits excellent sensing performance. Overall, this study provides a strategy for realizing high-performance dichlorodiethyl sulfide gas sensors. [ABSTRACT FROM AUTHOR]

Perovskite single crystals (SCs) have gained significant interest in various applications owing to their superior optoelectrical and physical characteristics as compared to polycrystalline films. However, a considerable portion of incident light is typically reflected at the surface of perovskite SCs, leading to insufficient light absorption within the crystal bulk, ultimately resulting in reduced performance of SC‐based photodetectors. In the present work, an inverted pyramid‐shaped structure is in situ introduced on the surface of an MAPbBr3 SC during the crystal growth process, which can reduce light reflection in the surface region and enhance light absorption of the SC. Additionally, the hydrophobic small molecule copper (II) phthalocyanine (CuPc) is thermally evaporated onto the SC, forming a CuPc/MAPbBr3 heterojunction for the first time. The CuPc/pyramid‐shaped MAPbBr3 heterojunction‐based photodetector exhibits self‐powered characteristics and superior optoelectrical performance, achieving a photocurrent of greater than 10−5 A (10−7 A), a responsiveness of 257 mA W−1 (8.84 mA W−1), and a detection rate of 2.98 × 1012 Jones (1.02 × 1011 Jones) at −2 V (0 V) bias. Simultaneously, the device demonstrates excellent long‐term stability under high humidity conditions, retaining 90.5% of its initial photocurrent even after 60 days in a 60–80% humidity environment. [ABSTRACT FROM AUTHOR]

Compared with polycrystalline films, perovskite single crystal is considered as a promising photoelectric material due to its unique advantages in quantum efficiency and carrier diffusion length. In this work, the micron-thickness MAPbBr3 single crystal was prepared through a highly repeatable process based on the crystal seed dissolution-growth method. A heterojunction of MAPbBr3/WO3 single crystal was realized through a simple thermal evaporation process, and the integrated C/MAPbBr3/WO3/C device demonstrated self-powered characteristics and high photoelectric performance, which showed good responsivity of about 111 mA/W, detectivity of 9.64×1011 Jones and fast response speed (0.11/0.56 ms). Meanwhile, the device exhibited good rectification performance (ratio of 125 at ±2 V) and reduced dark current due to the built-in electric field formed in the heterojunction. This study provides a facile, flexible, and highly repeatable method for the preparation of high-performance photodetectors based on MAPbBr3 single crystals with micrometer thickness. [ABSTRACT FROM AUTHOR]

Metal halide-perovskite-based photodetectors have recently emerged as a class of promising optoelectronic devices in various fields. Meanwhile, nano/microstructuring perovskite-based photodetectors are a facile integration with complementary metal-oxide semiconductors for miniaturized imaging systems. However, there are still challenges to be overcome in reducing the losses caused by light reflection on the surface of microstructural perovskites. In this work, surface microstructure engineering is employed in MAPbBr 3 microsheets for reducing light reflection and improving light absorption, resulting in high-performance perovskite photodetectors. MAPbBr 3 microsheets, which possess different surface morphologies of flat, upright hemisphere arrays and inverted hemisphere arrays (IHAs), are fabricated by a simple microstructure template-assisted space confinement process. The light absorption capacity of IHA MAPbBr 3 is significantly higher than that of the other two structures. Hence, IHA photodetectors with excellent figures of merit, including low dark current, decent responsivity, and fast speed, are achieved. Furthermore, the noise of the IHA photodetectors is only ∼10 -13 A/ H z , which results in the superior sensitivity for weak light detection with a specific detectivity up to 10 11 Jones. Our results demonstrate that surface engineering is a simple, low-cost, yet effective approach to improve the performance of nano-/micro-optoelectronic devices.