Publications by authors named "Xiangshun Geng"

Metal halide perovskites exhibit great promise for utilization in X-ray detection owing to their excellent optoelectronic properties and high X-ray attenuation capabilities. However, fabricating large-area thick films for high-performance perovskite X-ray detection remains challenging. This study develops an in situ crystal growth and fusing-confined approach to prepare high-quality, large-scale perovskite quasi-monocrystalline thick junctions.

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Recently, the combination of two-dimensional (2D) materials and perovskites has gained increasing attention in optoelectronic applications owing to their excellent optical and electrical characteristics. Here, we report a self-driven photodetector consisting of a monolayer graphene sheet and a centimeter-sized CHNHPbBr single crystal, which was prepared using an optimized wet transfer method. The photodetector exhibits a short response time of 2/30 μs by virtue of its high-quality interface, which greatly enhances electron-hole pair separation in the heterostructure under illumination.

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As a new-generation photoelectric material, perovskites have attracted researchers' attention due to their excellent optoelectronic properties. However, the existence of defects inevitably causes structural degradation and restricts their performance, which need to be further improved by post-treatment. At present, post-treatments mostly focus on non-contact treatments, which may constrain the effect since the influence on the perovskites caused by the direct contact is much more straightly.

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In recent years, flexible micro-pressure sensors have been used widely in wearable health monitoring applications due to their excellent flexibility, stretchability, non-invasiveness, comfort wearing and real-time detection. According to the working mechanism of the flexible micro-pressure sensor, it can be classified as piezoresistive, piezoelectric, capacitive and triboelectric types. Herein, an overview of flexible micro-pressure sensors for wearable health monitoring is presented.

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Lead halide perovskites have made remarkable progress in the field of radiation detection owing to the excellent and unique optoelectronic properties. However, the instability and the toxicity of lead-based perovskites have greatly hindered its practical applications. Alternatively, lead-free perovskites with high stability and environmental friendliness thus have fascinated significant research attention for direct X-ray detection.

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Sensing sensitivity is one of the crucial parameters for quartz crystal microbalance (QCM) sensors. Herein, we study the overtone mass sensitivity of a QCM sensor with an asymmetric N-M type electrode configuration. In order to overcome the deficiency that the sensitivity of the QCM sensor with an asymmetric electrode cannot be calculated by Sauerbrey's equation, we design the electrochemical electrodeposition experiments to measure it.

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Pb-free perovskite material is considered to be a promising material utilized in next-generation X-ray detectors due to its high X-ray absorption coefficient, decent carrier transport properties, and relatively low toxicity. However, the pixelation of the perovskite material with an industry-level photolithography processing method remains challenging due to its poor structural stability. Herein, we use CsAgBiBr perovskite material as the prototype and investigate its interaction with photolithographic polar solvents.

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With the in-depth application of quartz crystal microbalance (QCM) sensors in the fields of science and engineering, there is an urgent need for QCM sensors with high mass sensitivity. The mass sensitivity of a QCM is closely related to its resonance frequency, and the high resonance frequency leads to improve its mass sensitivity. However, the resonance frequency of a QCM resonator cannot be increased all the time due to the fragility of quartz wafer and the limits of energy trapping effect.

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We report an artificial eardrum using an acoustic sensor based on two-dimensional MXene (TiCT), which mimics the function of a human eardrum for realizing voice detection and recognition. Using MXene with a large interlayer distance and micropyramid polydimethylsiloxane arrays can enable a two-stage amplification of pressure and acoustic sensing. The MXene artificial eardrum shows an extremely high sensitivity of 62 kPa and a very low detection limit of 0.

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As a new generation of Zn-ion storage systems, Zn-ion hybrid supercapacitors (ZHSCs) garner tremendous interests recently from researchers due to the perfect integration of batteries and supercapacitors. ZHSCs have excellent integration of high energy density and power density, which seamlessly bridges the gap between batteries and supercapacitors, becoming one of the most viable future options for large-scale equipment and portable electronic devices. However, the currently reported two configurations of ZHSCs and corresponding energy storage mechanisms still lack systematic analyses.

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Single-crystal (SC) perovskite is currently a promising material due to its high quantum efficiency and long diffusion length. However, the reported perovskite photodetection range (<800 nm) and response time (>10 μs) are still limited. Here, to promote the development of perovskite-integrated optoelectronic devices, this work demonstrates wider photodetection range and shorter response time perovskite photodetector by integrating the SC CHNHPbBr (MAPbBr) perovskite on silicon (Si).

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MXenes have attracted great attention for their potential applications in electrochemical and electronic devices due to their excellent characteristics. Traditional sound sources based on the thermoacoustic effect demonstrated that a conductor needs to have an extremely low heat capacity and high thermal conductivity. Hence, a thin MXene film with a low heat capacity per unit area (HCPUA) and special layered structure is emerging as a promising candidate to build loudspeakers.

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Organometal trihalide perovskites (OTPs) are promising optoelectronic materials for high-performance photodetectors. However, up to now, traditional polycrystal OTP-based photodetectors have demonstrated limited effective photo-sensing range. Recently, bulk perovskite single crystals have been seen to have the potential for position-sensitive photodetection.

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Due to its excellent flexibility, graphene has an important application prospect in epidermal electronic sensors. However, there are drawbacks in current devices, such as sensitivity, range, lamination, and artistry. In this work, we have demonstrated a multilayer graphene epidermal electronic skin based on laser scribing graphene, whose patterns are programmable.

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