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Epitaxial Graphene Sensors Combined with 3D Printed Microfluidic Chip for Heavy Metals Detection
摘要： Two-dimensional materials may constitute key elements in the development of a sensing platform where extremely high sensitivity is required, since even minimal chemical interaction can generate appreciable changes in the electronic state of the material. In this work, we investigate the sensing performance of epitaxial graphene on Si-face 4H-SiC (EG/SiC) for liquid-phase detection of heavy metals (e.g., Pb). The integration of preparatory steps needed for sample conditioning is included in the sensing platform, exploiting fast prototyping using a 3D printer, which allows direct fabrication of a microfluidic chip incorporating all the features required to connect and execute the Lab-on-chip (LOC) functions. It is demonstrated that interaction of Pb2+ ions in water-based solutions with the EG enhances its conductivity exhibiting a Langmuir correlation between signal and Pb2+ concentration. Several concentrations of Pb2+ solutions ranging from 125 nM to 500 μM were analyzed showing good stability and reproducibility over time.
关键词： heavy metals detection,3D printed flow cell,reusable lab-on-chip,epitaxial graphene,high sensitivity
更新于2025-09-23 15:23:52
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A highly sensitive photocatalytic plastic optic-fiber sensor for selective detection of phenol in aqueous solutions
摘要： We present a highly sensitive photocatalytic plastic optic-fiber (POF) sensor for the selective detection of phenol in aqueous solutions. To obtain high sensitivity and low limit of detection (LOD) of the sensor, part of the POF cladding was removed and replaced by a Canada balsam doped with GeO2 (CBG); a UV-visible-light-driven photocatalytic material, that is a CdS-sensitized Er3+YAlO3/SiO2/TiO2 (EYST) composite, was coated on the CBG film. To realize highly selective detection of phenol in water, a high phenol permselectivity and pH independence polymer membrane was fixed on the CdS-sensitized EYST-CBG-coated POF. Furthermore, a model was developed to show that the phenol concentration can be determined by measuring the change in transmitted light intensity of the POF sensor and the sensitivity of the sensors can be improved by employing the CdS-sensitized EYST film. The results showed that the proposed photocatalytic POF sensor has a high sensitivity of -0.39 (mg·mL-1)-1 and low LOD of 15 μg·L-1 for the selective detection of phenol in aqueous solutions with pH ranging from 2.0 to 14.0.
关键词： Cds sensitization,Phenol concentration,High sensitivity and selectivity,Upconversion luminescence agent,Plastic optical fiber,TiO2 composite film
更新于2025-09-23 15:23:52
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Sensitivity Enhancement of a Surface Plasmon Resonance with Tin Selenide (SnSe) Allotropes
摘要： Single layers of tin selenide (SnSe), which have a similar structure as graphene and phosphorene, also show excellent optoelectronic properties, and have received much attention as a two-dimensional (2D) material beyond other 2D material family members. Surface plasmon resonance (SPR) sensors based on three monolayer SnSe allotropes are investigated with the transfer matrix method. The simulated results have indicated that the proposed SnSe-containing biochemical sensors are suitable to detect different types of analytes. Compared with the conventional Ag-only film biochemical sensor whose sensitivity is 116°/RIU, the sensitivities of these SnSe-based biochemical sensors containing α-SnSe, δ-SnSe, ε-SnSe, were obviously increased to 178°/RIU, 156°/RIU and 154°/RIU, respectively. The diverse biosensor sensitivities achieved with these three SnSe allotropes suggest that these 2D materials can adjust SPR sensor properties.
关键词： SPR sensor,high sensitivity,SnSe allotrope
更新于2025-09-23 15:22:29
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A novel “turn-on” mitochondria-targeting near-infrared fluorescent probe for H2S detection and in living cells imaging
摘要： Hydrogen sulfide (H2S) has been considered to be involved in cytoprotective processes and redox signaling. It is very meaningful to track and analyze it in mitochondria. Herein, we report a novel “turn-on” mitochondria-targeting near-infrared fluorescent probe (Mito-NIR-SH) for detection of H2S in living cells, which was designed and synthesized by introducing 2,4-dinitrophenyl as fluorescence quenching group and H2S response moiety into Changsha near-infrared fluorophore (CS-OH). The structure of the fluorophore and the probe were characterized by 1H NMR, 13C NMR and mass spectrometry. Meanwhile, Mito-NIR-SH could quantitatively detect H2S at concentrations ranging from 0 to 30 μM with a detection limit as low as 89.3 nM, showing good chemical stability, fast “turn-on” response, selectively mitochondrial location, as well as high sensitivity and selectivity toward H2S. Based on this, it was successfully applied to imaging exogenous and endogenous H2S in living HeLa cells via confocal fluorescence microscopy.
关键词： High sensitivity and selectivity,Near-infrared fluorescent probe,Hydrogen sulfide,Mitochondria-targeting,Bioimaging
更新于2025-09-23 15:22:29
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Low-Power-Operating 3C-SiC Ultraviolet Photodetector fora?￡Elevated Temperature Applications
摘要： This work demonstrates the systematic investigation of the effects of high temperature on key performance parameters including speed, sensitivity, stability, and repeatability of a 3C-SiC/Si ultraviolet (UV) photodetector (PD) at various operating temperatures ranging from 50°C to 200°C. The device with very low dark current (≈ 0.08 pA) exhibited high sensitivity of 4466 and fast rise and decay times of 0.34 s and 0.30 s at 50°C to exposure of 254 nm UV light at a bias voltage of 20 V. Additionally, the device showed very good performance at a low operating voltage of 0.5 V and high temperature of 200°C, with a rise time of 2.68 s and decay time of 1.44 s, while maintaining good stability and repeatability. The slight decrease in performance (sensitivity from 4466 to 932) at 200°C was attributed to the increase in lattice scattering at elevated temperatures, leading to a decrease in carrier mobility. Moreover, the device was fabricated using a very cost-effective process flow. Consequently, this study can contribute to the development of low-power, fast, highly sensitive, and cost-effective 3C-SiC UVPDs for use in high-temperature photonic applications.
关键词： fast response,high sensitivity,High-temperature UVPD,low-voltage operation,3C-SiC
更新于2025-09-23 15:21:01
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Nucleation-controlled growth of superior lead-free perovskite Cs3Bi2I9 single-crystals for high-performance X-ray detection
摘要： The organic-inorganic hybrid lead halide perovskites have emerged as a series of star materials for solar cells, lasers and detectors. However, the issues raised by the toxic lead element and marginal stability due to the volatile organic components have severely limited their potential applications. In this work, we develop a nucleation-controlled solution method to grow large size high-quality Cs3Bi2I9 perovskite single crystals (PSCs). Using the technique, we harvest some centimeter-sized single crystals and achieved high device performance. We ?nd that X-ray detectors based on PSCs exhibit high sensitivity of 1652.3 μC Gyair?1 cm?2 and very low detectable dose rate of 130 nGyair s?1, both desired in medical diagnostics. In addition, its outstanding thermal stability inspires us to develop a high temperature X-ray detector with stable response at up to 100 °C. Furthermore, PSCs exhibit high X-ray imaging capability thanks to its negligible signal drifting and extremely high stability.
关键词： nucleation-controlled growth,high sensitivity,X-ray detection,lead-free,perovskite single crystals
更新于2025-09-23 15:21:01
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High-sensitivity strain sensor with an in-fiber air-bubble Fabry-Perot interferometer
摘要： We present a laser machining method for fabricating an all-fiber pillar-in-bubble Fabry-Perot interferometer (FPI), which is used for strain sensors with high sensitivity. The micro-structure of the air-bubble is fully controllable, especially the cavity length and sidewall thickness. The measured sensitivity of this strain sensor is as high as 56.69 pm/με, which is several times higher than that of most FPI strain sensors reported to date. This sensor also has a low-temperature sensitivity of 0.682 pm/°C, reducing the cross-sensitivity between tensile strain and temperature to 0.012 με/°C. Furthermore, such a sensor has the benefits of flexible design, simple fabrication, and high reproducibility, making it attractive for practical applications.
关键词： high sensitivity,fiber optic,Fabry-Perot interferometer,laser machining,strain sensor
更新于2025-09-23 15:21:01
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High-speed III-V based avalanche photodiodes for optical communicationsa??the forefront and expanding applications
摘要： Avalanche photodiodes (APDs), i.e., semiconductor devices, which convert and amplify optical signals into electrical signals, are used for optical communications and for imaging and medical applications. The major requirements for APDs in optical communications are high-speed operation for high data rates and high-sensitivity operation for extending the transmission reach. This paper overviews the achievements of high-speed APDs for 100-Gbit/s optical communications, focusing on III-V material systems, which are advantageous in terms of band engineering. The outlook for APDs in future optical communications is also described.
关键词： high-speed operation,high-sensitivity operation,III-V material systems,optical communications,Avalanche photodiodes
更新于2025-09-23 15:19:57
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High-sensitivity laser confocal tomography based on frequency-shifted feedback technique
摘要： Laser confocal tomography faces severe challenges in weak signal detection such as biological tissue imaging and low-re?ection interfaces measurement. An ultra-high sensitive optical confocal tomography based on laser frequency-shifted feedback imaging technology is presented, whose theoretical magni?cation can reach 10 6 notably without using high-gain detectors. In addition, this achievement possesses the same tomographic resolution as conventional laser confocal tomography without the need for spatial ?ltering devices. In this work, supported by theories and experiments, the lateral and vertical resolution, optical sensitivity, and system repeatability of LFCT and traditional LCT are investigated and analyzed quanti?cationally. Finally, comparison on the results of measuring the micro?uidic device and biological tissue sections is conducted.
关键词： Laser confocal tomography,High sensitivity,Frequency-shifted feedback,Optical measurement,Biological specimens imaging
更新于2025-09-23 15:19:57
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Synthesis and Properties of Highly Sensitive Ether Ring Fused <i>O</i>-Acyloxime Esters as Photoradical Initiator
摘要： High sensitivity of O-acyloxime ester, which is widely used as a photo radical polymerization initiator for color resist, was investigated. Introduction of an ether ring structure to the periphery of oxime was aimed at increasing rigidity of dye scaffold. As a result, the absorption spectrum at i-line (365 nm) became sharp, the absorption efficiency was greatly improved, and the sensitivity was increased by about five times as much as conventional linear type oximes by improving the radical generation quantum yield.
关键词： Photoradical initiator,i-Line,High sensitivity,Radical curing reaction,Ether ring-fused structure,Carbazole dye,O-Acyloxime ester
更新于2025-09-19 17:15:36