Research interests
  • Hybrid materials made of carbon nanotubes and semiconductor metal oxides for gas sensing applications.
  • Low dimensional nanostructures (nanoparticle and nanowires) of metal oxides for gas sensing applications.
  • Synthesis, characterizations, and applications of GRAPHENE.
  • Nanofibres via electrospinning for nanosensors, nanocatalysis, filtration, and protective clothing. 

Recent publications
  • Scalable fabrication of high-performance NO2 gas sensors based on tungsten oxide nanowires by on-chip growth and RuO2-functionalization.
    By:  Phung Thi Hong Van, Nguyen Hoang Thanh, Vu Van Quang, Nguyen Van Duy, Nguyen Duc Hoa, Nguyen Van Hieu  (ACS Appl Mater Interfaces)
    Abstract: The on-chip growth and surface-functionalization have been recently regarded as promising techniques for large-scale fabrication of high performance nanowires gas sensors. Here we demonstrate a good NO2 gas-sensing performance of the tungsten oxide nanowires (TONWs) sensors realized by scalable on-chip fabrication and RuO2-functionalization. The gas response (Rg/Ra) of the RuO2-functionalized TONWs to 5 ppm of NO2 was 186.1 at 250 °C, which increased up to ∼18.6-fold compared with that of the bare TONWs. On the contrary, the responses of the bare and functionalized sensors to 10 ppm of NH3, 10 ppm of H2S and 10 ppm of CO gases were very low of about 1.5, indicating the good selectivity. In addition, the TONW sensors fabricated by the on-chip growth technique exhibited a good reversibility up to 7 cycles switching from air-to-gas with a response of 19.8 ± 0.033 (to 1 ppm of NO2), and this value was almost the same (about 19.5 ± 0.027) for 11 cycles after three months storage in laboratory condition. The response and selectivity enhancement of RuO2-functionalzied TONWs sensors was attributed to the variation of electron depletion layer due to the formation of RuO2/TONWs Schottky junctions and/or the promotion of more adsorption sites for NO2 gas molecule on the surface of TONWs, whereas the good reversibility was attributed to the formation of the stable monoclinic WO3 from the single crystal of monoclinic W18O49 after annealing at 600 °C. Full paper
    Posted Sep 30, 2014, 3:25 AM by Sensors VN
  • Outstanding gas-sensing performance of graphene/SnO2 nanowire
    By:  Vu Van Quang, Nguyen Van Dung, Ngo Sy Trong, Nguyen Duc Hoa, Nguyen Van Duy, Nguyen Van Hieu  (Applied Physics Letter)
    Abstract: Schottky junctions (SJ) are considered devices for sensing applications due to their unique properties. Herein, we report on the design, facile fabrication and outstanding NO2 gas sensing properties of monolayer graphene (GP)/SnO2 nanowire (NW) SJ devices. The devices were prepared by directly growing single crystal SnO2 NWs on interdigitated Pt electrodes via thermal evaporation, followed by transferring a GP layer grown by chemical vapor deposition on top of the NW chip. The SJ-based sensor showed a reversible response to NO2 gas at concentrations of ppb levels with detection limits of about 0.024 ppb at a low operating temperature of 150oC and bias voltage (1 V) with a response/recovery time of less than 50 s. The outstanding gas-sensing characteristics of the device were attributed to tuning the Schottky barrier height and barrier width at the tiny area of contact between GP and SnO2 NW through the adsorption/desorption of gas molecules
    Posted Jun 26, 2014, 9:18 PM by Sensors VN
  • Effective decoration of Pd nanoparticles on the surface of SnO2 nanowires for enhancement of CO gas-sensing performance
    By:  Do Dang Trung, Nguyen Duc Hoa, Pham Van Tong, Nguyen Van Duy, T.D. Dao, H. V. Chung, and T. Nagao, Nguyen Van Hieu  (J. Hazardous Materials)
    Abstract: Decoration of noble metal nanoparticles (NPs) on the surface of semiconducting metal oxide nanowires (NWs) to enhance material characteristics, functionalization, and sensing abilities has attracted increasing interests from researchers worldwide. In this study, we introduce an effective method for the decoration of Pd NPs on the surface of SnO2 NWs to enhance CO gas-sensing performance. Single-crystal SnO2 NWs were fabricated by chemical vapor deposition, whereas Pd NPs were decorated on the surface of SnO2 NWs by in situ reduction of the Pd complex at room temperature without using any linker or reduction agent excepting the copolymer P123. The materials were characterized by advanced techniques, such as high-resolution transmission electron microscopy, scanning transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The Pd NPs were effectively decorated on the surface of SnO2 NWs. As an example, the CO sensing characteristics of SnO2 NWs decorated with Pd NPs were investigated at different temperatures. Results revealed that the gas sensor exhibited excellent sensing performance to CO at low concentration (1 ppm to 25 ppm) with ultrafast response–recovery time (in seconds), high responsivity, good stability, and reproducibility. Full paper
    Posted Jan 28, 2014, 9:21 PM by Sensors VN
  • In-stitute decoration of Pd nanocrystal on crystalline mesoporous NiO nanosheets for effective hydrogen gas sensors
    By:  Phan Van Tong, Nguyen Duc Hoa, Vu Van Quang, Nguyen Van Duy, Nguyen The Lam Nguyen Van Hieu (International Journal of Hydrogen Energy)
    Abstract: The synthesis of cost-effective, high-performance hydrogen gas sensors is eliciting increasing interest because of their advantages in early detection of hydrogen leakages. Herein, we report the in- situ synthesis and decoration of Pd nanocrystals (NCs) on the surface of mesoporous NiO nanosheets for effective hydrogen gas sensor application. The use of large specific surface area of the mesoporous NiO nanosheets and the catalytic activity of the Pd NCs are the key points to improve the hydrogen gas sensing performances through the enhancement of the interaction between the hydrogen molecule and the sensing surface. The mesoporous NiO nanosheets were fabricated by a surfactant-less hydrothermal method in sequence to thermal oxidation, whereas the Pd NCs were decorated by in-situ reduction of palladium complex. The crystal structure and growth mechanism of the materials were investigated by several advanced techniques. The gas-sensing measurements revealed that the Pd-NiO nanosheets based sensor exhibited effectively detection of hydrogen at low concentration with fast response, high sensitivity and stability.
    Posted Aug 1, 2013, 1:08 AM by Sensors VN
  • Polyaniline Nanowires-Based Electrochemical Immunosensor for Label Free Detection of Japanese Encephalitis Virus
    By: Chu Van Tuan, Tran Quang Huy, Nguyen Van Hieu, Mai Anh Tuan & Tran Trung (Analytical Letters)
    Abstract: Polyaniline (PANI) conducting polymers have attracted increasing interest as a transducer material for biosensors applications. In this study, we demonstrate the use of PANI nanowires (NWs) as immobilization platforms in the configuration of an electrochemical immunosensor for label free detection of Japanese encephalitis virus. The PANI NWs were synthesized on the surface of an interdigitated platinum (Pt) microelectrode via electrochemical growth. The morphology and characteristics of the PANI NWs on the Pt microelectrode were verified by scanning electron microscopy and Fourier transform infrared spectroscopy. The anti- Japanese encephalitis virus polyclonal IgG antibody was then covalently immobilized on the PANI NWs-coated Pt microelectrode by using 1-ethyl-3-(3-dimethyaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimde (NHS). The detection of Japanese encephalitis virus antigens was analyzed by electrochemical impedance spectroscopy (EIS). The developed PANI NWs-based electrochemical immunosensor could detect the Japanese encephalitis virus with a detection limit below 10 ng/ml. The results from EIS analysis also indicate that when the PANI NWs were exposed to nonspecific molecules, a negligible response was found, and it did not impact to the specificity of the sensor in the virus detection. This work shows the potential use of PANI NWs in electrochemical immunosensors for label free detection of other pathogens and small biomolecules.Full paper
    Posted Jul 11, 2013, 3:04 AM by Sensors VN
Showing posts 1 - 5 of 14. View more »

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