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Ab Initio Design of Graphene Block Enables Ultrasensitivity, Multimeter-Like Range Switchable Pressure Sensor
摘要： In pursuit of the next-generation pressure sensors, the fabrication of graphene-based devices is considered to be one of the most promising approaches to address the unsatisfied sensitivity within a wide pressure range. Here, an ab initio design based on the graphene block is proposed to realize a high-performance and multimeter-like range switchable pressure sensor. The sensor contains three designed graphene-based foams with different initial resistances, which enable continuous resistance-change behavior induced by the pressure. Specifically, the reduced graphene oxide (rGO) foam–based sensor demonstrates a three times resistance change within the pressure range of 0–300 Pa, the rGO/polyurethane (rGO/PU) foam–based sensor presents a six times resistance change within the pressure range of 0.09–30 kPa, and the selenium-functionalized rGO/PU (SFrGO/PU) foam–based sensor displays a resistance change of more than 1000-fold within the pressure range of 1–72 kPa. Such different initial resistances and responses endow the device with controllable estimating pressure ranges, offering a switchable multimeter-like function for various applications. This ab initio design, which is applicable to various 2D materials and operation modes, can provide a facile and feasible approach toward the next-generation pressure sensors and other application fields related to 2D materials.
关键词： ultrahigh sensitivity,pressure sensor,graphene block,ab initio design,multimeter-like
更新于2025-09-23 15:23:52
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An ultrasensitive luteolin sensor based on MOFs derived CuCo coated nitrogen-doped porous carbon polyhedron
摘要： Designing high-efficiency electrocatalysts for luteolin detection is essential and vital in biological and medical field. Herein, CuCo coated nitrogen-enriched porous carbon polyhedron (CuCo@NPCP) materials are fabricated as a highly sensitive electrochemical luteolin sensor by simple and mild approach. As characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, N2 adsorption-desorption isotherms and electrochemical methods, CuCo@NPCP materials possess high specific surface area, 3D porous framework, amounts of available active sites, which all contribute to the adsorption and catalysis for luteolin. Meanwhile, vast mesoporous structure of CuCo@NPCP further affords more mass transport channels and enhances the mass transfer capacity. Thanks to above-mentioned characteristics, optimal Cu1Co3@NPCP presents superior analytical performance: a wide linear range from 0.2 nM to 2.5 μM, a ultrahigh sensitivity of 134.57 μA μM-1 surpassing to other reported catalysts previously, a low detection limit of 0.08 nM, as well as satisfactory selectivity, reproducibility, and long-term stability. This work offers an attractive catalyst derived from MOFs for constructing effective luteolin sensors.
关键词： Luteolin sensor,Metal-organic framework derivatives,Ultrahigh sensitivity,Trace detection
更新于2025-09-23 15:21:01
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Design of freely suspended photonic crystal microfiber cavity sensors array in a general single mode fiber
摘要： We propose a novel design of refractive index (RI) sensor array based on ultrahigh sensitivity one dimensional (1D) photonic crystal microfiber (PCMF) cavities, which is referred as photonic crystal microfiber cavity sensors array (PCMF-CSA). The proposed PCMF-CSA consists of multiple channels connected in parallel. A transmission only containing the fundamental mode (FM) resonance of the PCMF cavity sensor for sensing purpose is created by connecting an additional PCMF bandgap filter to a PCMF cavity sensor in series on each channel. Due to the photonic bandgap (PBG) of the PCMF bandgap filter, the other high-order resonances are filtered out. With proper engineering of the PBG, multiple ultrahigh sensitivity PCMF cavity sensors can be integrated into microarrays without resonance overlap, and be detected simultaneously between a single input optical fiber and a single output optical fiber without the need for complicated coupling systems. The concept was demonstrated with 7-channel PCMF cavity sensor array containing PCMF bandgap filters. By using three-dimensional finite-difference time-domain (3D-FDTD) method, the performance of the device was investigated theoretically. The simulation results showed that the sensors on each channels can be monitored simultaneously from a single output spectrum. The numerical calculated RI sensitivities (S) for each sensing channel of the proposal 7-channel PCMF-CSA as high as 647.33 nm/RIU, 666.67 nm/RIU, 662.00 nm/RIU, 676.00 nm/RIU, 674.67 nm/RIU, 659.33 nm/RIU, 679.99 nm/RIU can be achieved, respectively. The average RI sensitivity as high as 666.57 nm/RIU can be obtained. Moreover, the extinction ratios of all resonant peaks exceed 20.0 dB. The crosstalk of all channels is lower than ?24.5 dB. To the best of our knowledge, this is the first silica PCMF sensors array geometry based on conventional single mode fiber (SMF) that features both high Q and S, and thus is potentially a promising platform for ultra-sensitive RI-based gas sensing with high parallel-multiplexing capability.
关键词： Ultrahigh sensitivity,Photonic crystal,Multiplexing,Microfiber cavity,Sensors array,3D-FDTD
更新于2025-09-10 09:29:36
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Enhanced NO2 gas sensing of a single-layer MoS2 by photogating and piezo-phototronic effects
摘要： NO2 sensors with ultrahigh sensitivity are demanded for future electronic sensing systems. However, traditional sensors are considerably limited by the relative low sensitivity, high cost and complicated process. Here, we report a simply and reliable flexible NO2 sensor based on single-layer MoS2. The flexible sensor exhibits high sensitivity to NO2 gas due to ultra-large specific surface area and the nature of two-dimensional (2D) semiconductor. When the NO2 is 400 ppb (parts per billion), compared with the dark and strain-free conditions, the sensitivity of the single-layer sensor is enhanced to 671% with a 625 nm red light-emitting diode (LED) illumination of 4 mW/cm2 power under 0.67% tensile strain. More important, the response time is dramatically reduced to ～16 s and it only needs ～65 s to complete 90% recovery. A theoretical model is proposed to discuss the microscopic mechanisms. We find that the remarkable sensing characteristics are the result of coupling among piezoelectricity, photoeletricity and adsorption-desorption induced charges transfer in the single-layer MoS2 Schottky junction based device. Our work opens up the way to further enhancements in the sensitivity of gas sensor based on single-layer MoS2 by introducing photogating and piezo-phototronic effects in mesoscopic systems.
关键词： photogating effect,single-layer MoS2,ultrahigh sensitivity,flexible NO2 sensor,piezo-phototronic effect
更新于2025-09-04 15:30:14