The Experts below are selected from a list of 3627 Experts worldwide ranked by ideXlab platform
Dapeng Yu - One of the best experts on this subject based on the ideXlab platform.
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graphene zno nanowire graphene vertical structure based fast response ultraviolet photodetector
Applied Physics Letters, 2012Co-Authors: Xuewen Fu, Zhimin Liao, Yangbo Zhou, Hanchun Wu, Jun Xu, Dapeng YuAbstract:time, and recovery speed of our UV detectors are 8 � 10 2 , 0.7s, and 0.5s, respectively, which are significantly improved compared to the conventional ZnO NWs photodetectors. The improved performance is attributed to the existence of Schottky barriers between ZnO NW and graphene electrodes. The graphene/ZnO NW/graphene vertical sandwiched structures may be promising candidates for integrated Optoelectronic Sensor devices. V C 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4724208] ZnO, as a wide direct band gap (3.37eV) compound semiconductor with large exciton binding energy (60meV), has been widely investigated for its potential applications in Optoelectronic devices, gas and chemical Sensors. 1,2 Due to large surface-to-volume ratio, ZnO nanowires (NWs) exhibit highly susceptible photoelectric properties by means of electron-hole generation or recombination during ultraviolet (UV) illumination. Therefore, ZnO NWs have great potential in high sensitivity and fast-response UV Sensors, 3 environmental monitors, and optical communications. 4 Recently, Hu et al. 5 reported ZnO NW based UV Sensors using Schottky contact formed between ZnO and Pt electrode and the device performance such as the sensitive and UV response, is much higher than that of the traditional ZnO NW photoconductivity based UV Sensors. The UV detectors based on Schottky barriers formed between ZnO NW and other metal electrodes, such as gold electrodes, have also been studied. 6,7 Nevertheless, metal electrodes are poor in transparency and can dramatically influence the absorption efficiency of the UV Sensors. Graphene, a monolayer sp 2 carbon atoms with unique physical properties, such as high mobility and conductivity, 8 high optical transparency 9 and mechanical flexibility, 10 etc., has attracted great research interest recently. The high conductive and optical transparent properties make graphene an ideal candidate for the application in transparent electrode. The Schottky barrier is also expected to be existed at the interface between ZnO nanowire and graphene, and it has been utilized for light-emitting diodes 11 and transparent nanogenerators. 12 In this letter, we have fabricated a vertical sandwich structure of graphene/ZnO NW/graphene. We demonstrate the high performance of our ZnO NW based vertical UV photodetector due to the existence of Schottky barriers between graphene electrodes and ZnO NW. The current on-off ratio of the UV detector is up to 8 � 10 2 at a illumination power density of 50lw/lm 2 , the photocurrent
Isiah M Warner - One of the best experts on this subject based on the ideXlab platform.
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ionic liquid based Optoelectronic Sensor arrays for chemical detection
RSC Advances, 2014Co-Authors: Waduge Indika S Galpothdeniya, Kevin S Mccarter, Sergio L De Rooy, Bishnu P Regmi, Susmita Das, Farhana Hasan, Attres Tagge, Isiah M WarnerAbstract:Development of ionic liquid (IL)-based colorimetric Sensor arrays for detection and identification of chemicals in both the aqueous and vapor phases is reported. These facile and inexpensive Optoelectronic Sensors were fabricated by using ionic liquids (ILs) derived from readily available pH indicator dyes. A series of 12 different chemoSensory ILs were synthesized by pairing anionic pH indicator dyes with trihexyl(tetradecyl)phosphonium ([P66614]) cation via an ion exchange reaction. The incorporation of the [P66614] cation imparted hydrophobic characteristics to these ILs, and this induced hydrophobicity led to their desired low solubility in aqueous solutions, as well as eliminated the need for a specialized hydrophobic matrix/substrate for immobilization. In this manuscript, four different matrices, i.e. glass microfiber filter papers, cotton threads, silica thin layer chromatography (TLC) plates, and alumina TLC plates, were employed for fabrication of Sensor arrays. These Sensor arrays were used to analyze pH values of aqueous solutions as well as for detection of acidic and basic vapors. To further prove the applicability of these IL Sensor arrays as tools to sense closely related complex materials, the arrays were applied to successful discrimination of aqueous solutions of smoke from three commercially available cigarettes. The digital data generated from these Sensor arrays were used in developing predictive models for accurately identifying various analytes. Two approaches were used for developing the models, and two methods were applied for assessing the predictive accuracy of the models. Use of cotton threads as a matrix led to development of a more flexible, low volume, and lightweight array to estimate pH and detect a variety of vapors. These wearable arrays may possibly be incorporated into bandages, sweatbands, diapers, and similar systems. Overall, these IL-based Sensor arrays should provide a new research direction in the development of advanced colorimetric Sensor arrays for detection and identification of a range of analytes relevant to many different applications.
Hatice Altug - One of the best experts on this subject based on the ideXlab platform.
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handheld high throughput plasmonic bioSensor using computational on chip imaging
Light-Science & Applications, 2014Co-Authors: Arif E Cetin, Ahmet F Coskun, Betty C Galarreta, Min Huang, David Herman, Aydogan Ozcan, Hatice AltugAbstract:We demonstrate a handheld on-chip biosensing technology that employs plasmonic microarrays coupled with a lens-free computational imaging system towards multiplexed and high-throughput screening of biomolecular interactions for point-of-care applications and resource-limited settings. This lightweight and field-portable biosensing device, weighing 60 g and 7.5 cm tall, utilizes a compact Optoelectronic Sensor array to record the diffraction patterns of plasmonic nanostructures under uniform illumination by a single-light emitting diode tuned to the plasmonic mode of the nanoapertures. Employing a sensitive plasmonic array design that is combined with lens-free computational imaging, we demonstrate label-free and quantitative detection of biomolecules with a protein layer thickness down to 3 nm. Integrating large-scale plasmonic microarrays, our on-chip imaging platform enables simultaneous detection of protein mono- and bilayers on the same platform over a wide range of biomolecule concentrations. In this handheld device, we also employ an iterative phase retrieval-based image reconstruction method, which offers the ability to digitally image a highly multiplexed array of Sensors on the same plasmonic chip, making this approach especially suitable for high-throughput diagnostic applications in field settings. Light: Science & Applications (2014) 3, e122; doi:10.1038/lsa.2014.3; published online 3 January 2014
Song Qiu - One of the best experts on this subject based on the ideXlab platform.
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a flexible ultrasensitive Optoelectronic Sensor array for neuromorphic vision systems
Nature Communications, 2021Co-Authors: Qianbing Zhu, Dandan Yang, Chi Liu, Shun Feng, Maolin Chen, Yun Sun, Yanan Tian, Xiaomu Wang, Song QiuAbstract:The challenges of developing neuromorphic vision systems inspired by the human eye come not only from how to recreate the flexibility, sophistication, and adaptability of animal systems, but also how to do so with computational efficiency and elegance. Similar to biological systems, these neuromorphic circuits integrate functions of image sensing, memory and processing into the device, and process continuous analog brightness signal in real-time. High-integration, flexibility and ultra-sensitivity are essential for practical artificial vision systems that attempt to emulate biological processing. Here, we present a flexible Optoelectronic Sensor array of 1024 pixels using a combination of carbon nanotubes and perovskite quantum dots as active materials for an efficient neuromorphic vision system. The device has an extraordinary sensitivity to light with a responsivity of 5.1x10(7)A/W and a specific detectivity of 2x10(16) Jones, and demonstrates neuromorphic reinforcement learning by training the Sensor array with a weak light pulse of 1 mu W/cm(2). To emulate nature biological processing, highly-integrated ultra-sensitive artificial neuromorphic system is highly desirable. Here, the authors report flexible Sensor array of 1024 pixels using combination of carbon nanotubes and perovskite QDs as active matetials, achieving highly responsive device for reinforcement learning.
Xuewen Fu - One of the best experts on this subject based on the ideXlab platform.
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graphene zno nanowire graphene vertical structure based fast response ultraviolet photodetector
Applied Physics Letters, 2012Co-Authors: Xuewen Fu, Zhimin Liao, Yangbo Zhou, Hanchun Wu, Jun Xu, Dapeng YuAbstract:time, and recovery speed of our UV detectors are 8 � 10 2 , 0.7s, and 0.5s, respectively, which are significantly improved compared to the conventional ZnO NWs photodetectors. The improved performance is attributed to the existence of Schottky barriers between ZnO NW and graphene electrodes. The graphene/ZnO NW/graphene vertical sandwiched structures may be promising candidates for integrated Optoelectronic Sensor devices. V C 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4724208] ZnO, as a wide direct band gap (3.37eV) compound semiconductor with large exciton binding energy (60meV), has been widely investigated for its potential applications in Optoelectronic devices, gas and chemical Sensors. 1,2 Due to large surface-to-volume ratio, ZnO nanowires (NWs) exhibit highly susceptible photoelectric properties by means of electron-hole generation or recombination during ultraviolet (UV) illumination. Therefore, ZnO NWs have great potential in high sensitivity and fast-response UV Sensors, 3 environmental monitors, and optical communications. 4 Recently, Hu et al. 5 reported ZnO NW based UV Sensors using Schottky contact formed between ZnO and Pt electrode and the device performance such as the sensitive and UV response, is much higher than that of the traditional ZnO NW photoconductivity based UV Sensors. The UV detectors based on Schottky barriers formed between ZnO NW and other metal electrodes, such as gold electrodes, have also been studied. 6,7 Nevertheless, metal electrodes are poor in transparency and can dramatically influence the absorption efficiency of the UV Sensors. Graphene, a monolayer sp 2 carbon atoms with unique physical properties, such as high mobility and conductivity, 8 high optical transparency 9 and mechanical flexibility, 10 etc., has attracted great research interest recently. The high conductive and optical transparent properties make graphene an ideal candidate for the application in transparent electrode. The Schottky barrier is also expected to be existed at the interface between ZnO nanowire and graphene, and it has been utilized for light-emitting diodes 11 and transparent nanogenerators. 12 In this letter, we have fabricated a vertical sandwich structure of graphene/ZnO NW/graphene. We demonstrate the high performance of our ZnO NW based vertical UV photodetector due to the existence of Schottky barriers between graphene electrodes and ZnO NW. The current on-off ratio of the UV detector is up to 8 � 10 2 at a illumination power density of 50lw/lm 2 , the photocurrent