Zhong Gao

Publications

  1. A bio-inspired and switchable H+/OH− ion-channel for room temperature exhaled CO2 chemiresistive sensing
    Honghao Chen; Ruofei Lu; Yixun Gao; Xiaorui Yue; Haihong Yang; Hao Li; Yi-Kuen Lee; Paddy J. French; Yao Wang; Guofu Zhouab;
    Journal of Materials Chemistry A,
    Volume 11, Issue 21959-21971, 2023. DOI: https://doi.org/10.1039/D3TA04685K
    Abstract: ... Inspired by the CO2-induced reversible activation mechanism of the slow anion channel 1 (SLAC1) in plant stomatal guard cells during plant photosynthesis, we designed and prepared a CO2- switchable H+/OH− ion channel (CSPH ion channel). A high-performance chemiresistive room temperature CO2 sensor has been prepared based on this CSPH ion channel. The obtained CO2 room temperature sensor γ-CD-MOF@RhB exhibits high sensitivity (Rg/R0 = 1.50, 100 ppm), excellent selectivity, good stability (less than 5% reduction in 30 days response value), and 99.96% consistency with commercial infrared CO2 meter. The practical limit of detection (pLOD) of the γ-CD-MOF@RhB sensor reaches 10 ppm at room temperature toward CO2, which is the lowest for reported MOF-derived chemiresistive room temperature CO2 sensors so far. Ion conduction mechanism studies have shown that the CSPH ion channel behaves as a CO2-switchable H+/OH− ion channel with a switching point of approximately 60 000 ppm CO2. As an application attempt, the fabricated low pLOD CO2 sensor has been used for human exhaled CO2 detection to compare CO2 concentration in the breath of individuals before and after exercise and COVID-19. It was also logically indicated that the average concentration of human exhaled CO2 after COVID-19 recovery is different for undiseased subjects.

  2. High-Performance Flexible Strain Sensor Fabricated Using Laser Transmission Pyrolysis
    Shaogang Wang; Huiru Yang; Qihang Zong; Qianming Huang; Chunjian Tan; Chenshan Gao; Shizhen Li; Huaiyu Ye; Guoqi Zhangand; Paddy French;
    IEEE Sensors Journal,
    2023. DOI: doi: 10.1109/JSEN.2023.3337233
    Keywords: ... Stretchable strain sensors, Metal film, UV laser, Laer transmission pyrolysis, PDMS pattering..

    Abstract: ... In recent years, metal crack-based stretchable flexible strain sensors have attracted significant attention in wearable device applications due to their extremely high sensitivity. However, the trade-off between sensitivity and detection range has been an intractable dilemma, severely limiting their practical applications. Herein, we propose a laser transmission pyrolysis technology for fabricating high-performance flexible strain sensors based on (Au) metal cracks with the microchannel array on the polydimethylsiloxane (PDMS) surface. The fabricated flexible strain sensors exhibit high sensitivity (gauge factor of 2448), wide detection range (59% for tensile strain), precise strain resolution (0.1%), fast response and recovery times (69 ms and 141 ms), and robust durability (over 3000 cycles). In addition, experiment and simulation results reveal that introducing a microchannel array enables the stress distribution strategy on the sensor surface, which significantly improves the sensing sensitivity compared to conventional flat surface sensors. Based on the excellent performance, the sensors are applied to detect subtle physiological signals such as pulse and swallowing, as well as to monitor large-scale motion signals such as knee flexion and finger bending, demonstrating their potential applications in health monitoring, human-machine interactions, and electronic skin

  3. Carbon-Iron Electron Transport Channels in Porphyrin–Graphene Complex for ppb-Level Room Temperature NO Gas Sensing
    Yixun Gao; Jianqiang Wang; Yancong Feng; Nengjie Cao; Hao Li; Nicolaas Frans de Rooij; Ahmad Umar; Paddy J. French; Yao Wang; Guofu Zhou;
    SMALL,
    pp. 9, 2022. DOI: 10.1002/smll.202103259
    Abstract: ... It is a great challenge to develop efficient room-temperature sensing materials and sensors for nitric oxide (NO) gas, which is a biomarker molecule used in the monitoring of inflammatory respiratory diseases. Herein, Hemin (Fe (III)-protoporphyrin IX) is introduced into the nitrogen-doped reduced graphene oxide (N-rGO) to obtain a novel sensing material HNGethanol. Detailed XPS spectra and DFT calculations confirm the formation of carbon–iron bonds in HNG-ethanol during synthesis process, which act as electron transport channels from graphene to Hemin. Owing to this unique chemical structure, HNG-ethanol exhibits superior gas sensing properties toward NO gas (Ra/Rg = 3.05, 20 ppm) with a practical limit of detection (LOD) of 500 ppb and reliable repeatability (over 5 cycles). The HNG-ethanol sensor also possesses high selectivity against other exhaled gases, high humidity resistance, and stability (less than 3% decrease over 30 days). In addition, a deep understanding of the gas sensing mechanisms is proposed for the first time in this work, which is instructive to the community for fabricating sensing materials based on graphene-iron derivatives in the future.

  4. Carbon Dots Embedded in Cellulose Film: Programmable, Performance-Tunable, and Large-Scale Subtle Fluorescent Patterning by in Situ Laser Writing
    Yuanyuan Guo; Quan Wang; Hao Li; Yixun Gao; Xuezhu Xu; Biao Tang; Yao Wang; Bai Yang; Yi-Kuen Lee; Paddy J. French; Guofu Zhou;
    ACS Nano,
    Volume 16, pp. 11, 2022. DOI: 10.1021/acsnano.1c09999
    Keywords: ... fluorescent pattern, tunable intensity, surface microstructure, laser direct writing, carbon dots.

    Abstract: ... Fluorescent patterns with multiple functions enable highsecurity anti-counterfeiting labels. Complex material synthesis and patterning processes limit the application of multifunctional fluorescent patterns, so the technology of in situ fluorescent patterning with tunable multimodal capabilities is becoming more necessary. In this work, an in situ fluorescent patterning technology was developed using laser direct writing on solid cellulose film at ambient conditions without masks. The fluorescent intensity and surface microstructure of the patterns could be adjusted by programmable varying of the laser parameters simultaneously. During laser direct writing, carbon dots are generated in situ in a cellulose ester polymer matrix, which significantly simplifies the fluorescent patterning process and reduces the manufacturing cost. Interestingly, the tunable fluorescent intensity empowers the fabrication of visual stereoscopic fluorescent patterns with excitation dependence, further improving its anti-counterfeiting performance. The obtained fluorescent patterns still show ultrahigh optical properties after being immersed in an acid/base solution (pH 5−12) over one month. In addition, the anti-UV performance of the obtained laser-patterned film with transmittance around 90% is comparable to that of commercial UV-resistant films. This work provided an advanced and feasible approach to fabricating programmable, performance-tunable, subtle fluorescent patterns in large-scale for industrial application.

  5. Assembly of Core/Shell Nanospheres of Amorphous Hemin/ Acetone-Derived Carbonized Polymer with Graphene Nanosheets for Room-Temperature NO Sensing
    Jianqiang Wang; Yixun Gao; Fengjia Chen; Lulu Zhang; Hao Li; Nicolaas Frans de Rooij; Ahmad Umar; Yi-Kuen Lee; Paddy J. French; Bai Yang, Yao Wang; Guofu Zhou;
    Applied Materials and Interfaces,
    Volume 14, December 2022. DOI: https://doi.org/10.1021/acsami.2c16769
    Keywords: ... nitric oxide sensor, Hemin, graphene, carbonized polymer, core−shell structure.

    Abstract: ... Implementing parts per billion-level nitric oxide (NO) sensing at room temperature (RT) is still in extreme demand for monitoring inflammatory respiratory diseases. Herein, we have prepared a kind of core−shell structural Hemin-based nanospheres (Abbr.: Hemin-nanospheres, defined as HNSs) with the core of amorphous Hemin and the shell of acetone-derived carbonized polymer, whose core−shell structure was verified by XPS with argon-ion etching. Then, the HNSassembled reduced graphene oxide composite (defined as HNS-rGO) was prepared for RT NO sensing. The acetone-derived carbonized polymer shell not only assists the formation of amorphous Hemin core by disrupting their crystallization to release more Fe−N4 active sites, but provides protection to the core. Owing to the unique core−shell structure, the obtained HNS-rGO based sensor exhibited superior RT gas sensing properties toward NO, including a relatively higher response (Ra/Rg = 5.8, 20 ppm), a lower practical limit of detection (100 ppb), relatively reliable repeatability (over 6 cycles), excellent selectivity, and much higher long-term stability (less than a 5% decrease over 120 days). The sensing mechanism has also been proposed based on charge transfer theory. The superior gas sensing properties of HNS-rGO are ascribed to the more Fe−N4 active sites available under the amorphous state of the Hemin core and to the physical protection by the shell of acetonederived carbonized polymer. This work presents a facile strategy of constructing a high-performance carbon-based core−shell nanostructure for gas sensing.

  6. A Low-Spur Fractional-N PLL Based on a Time-Mode Arithmetic Unit
    Gao, Zhong; He, Jingchu; Fritz, Martin; Gong, Jiang; Shen, Yiyu; Zong, Zhirui; Chen, Peng; Spalink, Gerd; Eitel, Ben; Alavi, Morteza S.; Staszewski, Robert Bogdan; Babaie, Masoud;
    IEEE Journal of Solid-State Circuits,
    pp. 1-20, 2022. DOI: 10.1109/JSSC.2022.3209338

  7. A 2.6-to-4.1GHz Fractional-N Digital PLL Based on a Time-Mode Arithmetic Unit Achieving -249.4dB FoM and -59dBc Fractional Spurs
    Gao, Zhong; He, Jingchu; Fritz, Martin; Gong, Jiang; Shen, Yiyu; Zong, Zhirui; Chen, Peng; Spalink, Gerd; Eitel, Ben; Yamamoto, Ken; Staszewski, Robert Bogdan; Alavi, Morteza S.; Babaie, Masoud;
    In 2022 IEEE International Solid- State Circuits Conference (ISSCC),
    pp. 380-382, 2022. DOI: 10.1109/ISSCC42614.2022.9731561

  8. A DPLL-Based Phase Modulator Achieving -46dB EVM with A Fast Two-Step DCO Nonlinearity Calibration and Non-Uniform Clock Compensation
    Gao, Zhong; Fritz, Martin; He, Jingchu; Spalink, Gerd; Staszewski, Robert Bogdan; Alavi, Morteza S.; Babaie, Masoud;
    In 2022 IEEE Symposium on VLSI Technology and Circuits (VLSI Technology and Circuits,
    pp. 14-15, 2022. DOI: 10.1109/VLSITechnologyandCir46769.2022.9830398

  9. Room temperature ppt-level NO2 gas sensor based on SnOx/SnS nanostructures with rich oxygen vacancies
    Hongyu Tang; Chenshan Gao; Huiru Yang; Leandro Nicolas Sacco; Robert Sokolovskij; Hongze Zheng; Huaiyu Ye; Sten Vollebregt; Hongyu Yu; Xuejun Fan; Guoqi Zhang;
    2D Materials,
    2021. DOI: 10.1088/2053-1583/ac13c1

  10. A DFT study of As doped WSe2: A NO2 sensing material with ultra-high selectivity in the atmospheric environment
    Zhaokun Wang; Chenshan Gao; Shuhan Hou; Huiru Yang; Ziyuan Shao; Siyuan Xu; Huaiyu Ye;
    Materials Today Communications,
    Volume 28, pp. 102654, 2021. DOI: 10.1016/j.mtcomm.2021.102654
    document

  11. Correction: The inactivation mechanism of chemical disinfection against SARS-CoV-2: from MD and DFT perspectives
    Tan, Chunjian; Gao, Chenshan; Zhou, Quan; Van Driel, Willem; Ye, Huaiyu; Zhang, GuoQi;
    RSC Adv.,
    Volume 11, pp. 3509-3509, 2021. DOI: 10.1039/D0RA90127J
    document

  12. The inactivation mechanism of chemical disinfection against SARS-CoV-2: from MD and DFT perspectives
    Tan, Chunjian; Gao, Chenshan; Zhou, Quan; Van Driel, Willem; Ye, Huaiyu; Zhang, GuoQi;
    RSC Adv.,
    Volume 10, pp. 40480-40488, 2020. DOI: 10.1039/D0RA06730J
    document

  13. Study on the effect of mixing proportion of micro- and nano-copper particles on sintering properties
    Xu Liu; Quan Zhou; Qipeng Liu; Honghao Tang; Chenshan Gao; Bin Xie; Sau Wee Koh; Huaiyu Ye; GuoQi Zhang;
    In 2020 21st International Conference on Electronic Packaging Technology (ICEPT),
    pp. 1-5, 2020. DOI: 10.1109/ICEPT50128.2020.9201937

  14. Recurrent Neural Network Control of a Hybrid Dynamic Transfemoral Prosthesis with EdgeDRNN Accelerator
    C*. Gao; R*. Gehlhar; A. D Ames; S.-C. Liu; T. Delbruck;
    In 2020 IEEE International Conference on Robotics and Automation (ICRA),
    2020. DOI: 10.1109/ICRA40945.2020.9196984

  15. PVP-Mediated Galvanic Replacement Synthesis of Smart Elliptic Cu− Ag Nanoflakes for Electrically Conductive Pastes
    Yu Zhang; Pengli Zhu; Gang Li; Zhen Cui; Chengqiang Cui; Kai Zhang; Jian Gao; Xin Chen; GuoQi Zhang; Rong Sun; Chingping Wong;
    ACS Applied Materials & Interfaces,
    2019.

  16. A DFT study of In doped Tl2O: a superior NO2 gas sensor with selective adsorption and distinct optical response
    Chenshan Gao; Yingying Zhang; Huiru Yang; Yang Liu; Yufei Liu; Jihe Dua; Huaiyu Ye; GuoQi Zhang;
    Applied Surface Science,
    2019. DOI: 10.1016/j.apsusc.2019.07.067

  17. High-performance humidity sensor using Schottky-contacted SnS nanoflakes for noncontact healthcare monitoring
    Hongyu Tang; Yutao Li; Huaiyu Ye; Fafei Hu; Chenshan Gao; Luqi Tao; Tao Tu; Guangyang Gou; Xianping Chen; Xuejun Fan; Tianling Ren; GuoQi Zhang;
    Nanotechnology,
    Volume 31, Issue 5, pp. 055501, Nov 2019. DOI: 10.1088/1361-6528/ab414e
    document

  18. A photovoltaic window with sun-tracking shading elements towards maximum power generation and non-glare daylighting
    Yuan Gao; Jianfei Dong; Olindo Isabella; Rudi Santbergen; Hairen Tan; Miro Zeman; GuoQi Zhang;
    Applied Energy,
    Volume 228, pp. 1454-1472, 2018.

  19. First-Principles Study of Nitric Oxide Sensor Based on Blue Phosphorus Monolayer
    HC Luo; RS Meng; H Gao; X Sun; J Xiao; HY Ye; GuoQi Zhang; XP Chen;
    IEEE Electron Device Letters,
    Volume 38, Issue 8, pp. 1139-1142, 2017.

  20. A 60 GHz 5-bit digital controlled phase shifter in a digital 40-nm CMOS technology without ultra-thick metals
    Hao Gao; Kuangyuan Ying; Marion Matters-Kammerer; Pieter Harpe; Bindi Wang; Bo Liu; Wouter Serdijn; Peter Baltus;
    Electronics Letters,
    August 12 2016. DOI: 10.1049/el.2016.0949 , Print ISSN 0013-5194, Online ISSN 1350-911X Available online: 12 August 2016.
    document

  21. Frequency locking and monitoring based on bi-directional terahertz radiation of a 3rd-order distributed feedback quantum cascade laser
    N. van Marrewijk; B. Mirzaei; D. Hayton; J. R. Gao; T. Y. Kao; Q. Hu; J. L. Reno;
    Journal of Infrared, Millimeter, and Terahertz Waves,
    Volume 36, Issue 12, pp. 1210-1220, December 2015.
    document

  22. BiCMOS integrated waveguide power combiner at submillimeter-wave frequencies
    Alonso-delPino, M.; Cavallo, D.; Thippur Shivamurthy, H.; Gao, H.; Spirito, M.;
    In 40th International Conference on Infrared, Millimeter, and Terahertz Waves,
    Honk Kong, Aug. 23-28 2015. DOI: 10.1109/IRMMW-THz.2015.7327937

  23. A digital to time converter with fully digital calibration scheme for ultra-low power ADPLL in 40 nm CMOS
    B. Wang; Y. H. Liu; P. Harpe; J. van den Heuvel; B. Liu; H. Gao; R. B. Staszewski;
    In 2015 IEEE International Symposium on Circuits and Systems (ISCAS),
    pp. 2289-2292, May 2015.

  24. Architectural complexity analysis for large-scale emergency rescue management systems: A preliminary study
    L. Gao; M.E. Warnier; S. van Splunter; L. Chenggen; F.M. Brazier;
    In K Pattipati (Ed.), Proceedings of the international conference on complex systems engineering (ICCSE),
    IEEE, pp. 1-6, 11 2015. harvest.

  25. BiCMOS integrated waveguide power combiner at submillimeter-wave frequencies
    M. Alonso-delPino; D. Cavallo; H. Thippur-Shivamurthy; H. Gao; M. Spirito;
    In 2015 40th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz),
    pp. 1-2, Aug 2015.

  26. HermesE: A 96-channel full data rate direct neural interface in 0.13 μm CMOS
    H. Gao; R.M. Walker; P. Nuyujukian; K.A.A. Makinwa; K.V. Shenoy; B. Murmann; T.H.Y. Meng;
    IEEE Journal of Solid State Circuits,
    Volume 47, Issue 4, pp. 1043-1055, April 2012. Harvest Article number: 6158616.

  27. Layer-by-layer deposition of colloidal semiconductor nanocrystals for integration of infrared photon-detectors on 3D topography
    J. Wei; Y. Gao; A.J. Houtepen; G. Pandraud; P.M. Sarro;
    In 16th International Solid-State Sensors, Actuators and Microsystems Conference (TRANSDUCERS 2011),
    Beijing, China, pp. 1749-1752, Jun. 2011. ISBN 978-1-4577-0157-3; DOI 10.1109/TRANSDUCERS.2011.5969819.

  28. A 96-channel full data rate direct neural interface in 0.13um CMOS
    R.M. Walker; H. Gao; P. Nuyujukian; K.A.A. Makinwa; K.V. Shenoy; T. Meng; B. Murmann;
    In Dig. Techn. Paper IEEE Symposium on VLSI Circuits (VLSI),
    IEEE, pp. 144‒145, June 2011.

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