Xiaohuan Huang

Formation of Carboxylic Acid-terminated Self-assembled Monolayers of Alkanethiols on GaAs (001) For Biosensing Applications

[tab title=”Project”]

The GaAs (001) surface exhibits high density of states located near midgap, even when prepared by molecular beam epitaxy. This results in a high surface carrier recombination velocity. Since these states are related to surface species whose chemical bonding is different from that in the bulk, construction of the 2D self-assembled monolayers (SAMs) is an important way to passivate the GaAs surface effectively, and prepare it for further integration with biofunctional molecules useful for biosensing and other applications in life sciences.

Numerous theoretical and experimental studies have confirmed that the long chain alkylthiolates [HS-(CH2)n-CH3] on GaAs(001) can be well-organized with a high degree of chain conformational ordering and direct S-(GaAs) bonding. But, for carboxyl terminated alkylthiolates [HS-(CH2)n-COOH], it is not easy to obtain well-ordered SAMs on GaAs. This is due to the high hydrophilicity of the carboxylic acid and formation of hydrogen-bonds between neighboring carboxylic groups.

The goal of my project is to investigate the process of formation of carboxylic acid-terminated SAMs on the GaAs (001) surface and determine experimental conditions suitable for their optimized deposition. The formation of SAMs on GaAs will be monitored with in situ photoluminescence. Ex situ characterization will include Fourier transform infrared spectroscopy measurements, x-ray photoelectron spectroscopy, atomic force microscopy and some other surface characterization techniques. The stability of SAMs in air and water will also be investigated to evaluate the suitability of the SAM-GaAs architectures for biosensing and fabrication of innovative optoelectronic devices.


[tab title=”Curriculum”]

  • 2007-2010
    Ph.D. in Organic Chemistry
    Wuhan University, China

  • 2005-2007
    M.Sc. in Organic Chemistry
    Wuhan University, China

  • 2001-2005
    B.Sc. in applied chemistry
    Hubei Normal University, China.

      [tab title=”Publications”]

      Articles published or accepted in refereed journals:
      • X.H. Huang, Y. Lu, Y.B. He and Z.H. Chen. A Novel Metal-macrocycle Complex as Fluorescent Sensor for Biological Phosphate Ion in Aqueous Solution. Eur. J. Org. Chem. 2010, 1921-1927.
      • X.H. Huang, Y.B. He, C.G. Hu and Z.H. Chen. Selective Metal-Ligand Fluorescent Chemosensor for Dihydrogen Phosphate via Intermolecular Excimer Formation in Water. Eur. J. Org. Chem. 2009, 1549-1553
      • X.H. Huang, Y.B. He, C.G. Hu and Z.H. Chen. Synthesis and Chiral Recognition Properties of Novel Fluorescent Chemosensors for Amino Acid. J. Fluoresc. 2009, 19, 97-104.
      • X.H. Huang, Y.B. He, Z.H. Chen and C.G. Hu. Colorimetric Sensors for Anion Recognition Based on the Proton Transfer Signaling Mechanism. Chin. J. Chem. 2009, 27, 1526-1530.
      • X.H. Huang, Y.B. He, Z.H. Chen, C.G. Hu and G.Y. Qing. Novel chiral fluorescent chemosensors for malate and acidic amino acids based on two-arm thiourea and amide. Can. J. Chem. 2008, 86, 170-176.
      • Z.H. Chen, Y. Lu, Y.B He and X.H Huang. Recognition of pyrophosphate anion in aqueous solution using the competition displacement method. Sensors and Actuators B: Chemical2010, 149, 407-412.
      • C.G. Hu, Y.B. He, Z.H. Chen and X.H. Huang. Enantioselective Fluorescent Sensor Based on Calix[4]arene and S-Binol for the Recognition of N-Boc-glutamate. Tetrahedron: Asymmetry 2009, 20, 104-110.
      • C.G. Hu, X.H. Huang, Z.H. Chen and Y.B. He. Enantioselective Fluorescent Sensor Based on Calix[4]arene and S-Binol for the Recognition of N-Boc-glutamate. Chin. J. Chem. 2009, 27, 157-162.
      • Z.H. Chen, Y.B. He, C.G. Hu and X.H. Huang. Preparation of a metal-ligand fluorescent chemosensor and enantioselective recognition of carboxylate anions in aqueous solution. Tetrahedron: Asymmetry 2008, 19, 2051-2057.
      • Z.H. Chen, Y.B. He, C.G. Hu, X.H. Huang and Ling Hu. Synthesis and chiral recognition properties of a novel colorimetric chiral sensor for carboxylic anions. Aust. J. Chem. 2008, 61, 310-315.

        [tab title=”Contact”]

        Xiaohuan Huang
        Department of Electrical and Computer Engineering
        Université de Sherbrooke
        2500 boul. de l’Université
        Sherbrooke, Québec
        J1K 2R1, CANADA

        Office: Rm. C1-3052
        Phone: 1-819-821-8000 x. 61210
        Email: xiaohuan.huang@usherbrooke.ca


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