Research Experience
Assistant Professor of National University of Singapore (2008.3 till now)

Postdoctoral Research Associate at National Renewable Energy Laboratory (NREL), USA, with Dr. Arthur J. Frank (2006.9-2008.2)

Postdoctoral Research Assistant, Swiss Federal Institute of Technology (EPFL), Lausanne, with Prof. Michael Grätzel (2002.12-2006.8)

Research Interests (click to read more)

Mesoscopic Charge Transport/Transfer in Advanced Energy Conversion/Storage Systems

While charge transport/transfer, both on the molecular and on the bulk level, are presently fairly well understood, their characterization on the mesoscopic scale is only at its beginning. These nanoscale charge transport/transfer processes, however, are important to both the frontier of fundamental science and applications to efficient energy conversion and storage devices, such as photovoltaics, photolysis, fuel cells, batteries, electroluminescent and electrochromic displays, etc. With dye-sensitized solar cells as the research platform, our work focuses on the fundamental studies of charge transport in nanostructured systems, such as electron/hole propagation in mesoscopic semiconductor films/interfaces, anion/cation transport in ionic mesoscopic systems/boundaries, and their applications for efficient photovoltaic devices and batteries.

Achieving controllable charge transport and consequently enhanced performance in functional heterogeneous nanostructures relies on our ability to synthesize integrated nanostructures with the desired architecture. Specific emphasis will be placed on solution-based syntheses and self-assembly techniques to take advantage of the current rapid progress in nanochemistry. In particular, syntheses of mesoscale composites of various material combinations, including organic dyes, organometallic complexes, polymeric, semiconducting and metallic nanoparticles, will be investigated for their chemical and multiphasic compatibility, size and morphological controllability, and synergetic functionality including quantum confinement effect, electronic/electrical properties, and optical band gap engineering.

Selected Publications (click to expand)

Q. Wang, K. Zhu, N. R. Neale, A. J. Frank, Constructing Ordered Sensitized Heterojunctions: Bottom-up Electrochemical Synthesis of p-type Semiconductors in Oriented n-TiO2 Nanotube Arrays. Nano Lett., in press (2009).

Q. Wang, Z. Zhang, S. M. Zakeeruddin, and M. Grätzel, Formation of Shallow Transport Levels under Visible Light Illumination Enhances the Performance of Dye-sensitized Solar Cell. J. Phys. Chem. C, 112, 7084 (2008).

Q. Wang, N. Evans, S. M. Zakeeruddin, I. Exnar, and M. Grätzel, Charging and Discharging Insulating Electrode Materials in High Energy Lithium Ion Batteries by Molecular Charge Transport Layers. J. Am. Chem. Soc., 129, 3163 (2007).

Q. Wang, S. Ito, M. Grätzel, F. Fabregat-Santiago, I. Mora-Seró, J. Bisquert, T. Bossho, and H. Imai, Characteristics of High Efficiency Dye-sensitized Solar Cells. J. Phys. Chem. B, 110, 25210 (2006).

Q. Wang, S. M. Zakeeruddin, D. Wang, I. Exnar, and M. Grätzel, Redox Targeting of Insulating Electrode Materials: A New Approach to High Energy Density Batteries. Angew. Chem. Int. Ed., 45, 8197 (2006).

H. J. Snaith, S. M. Zakeeruddin, Q. Wang, P. Pechy, and M. Grätzel, Dye-sensitized Solar Cells Incorporating a “Liquid” Hole Transporting Material. Nano Lett., 6, 2000 (2006).

Q. Wang, S. M. Zakeeruddin, Md. K. Nazeeruddin, R. Humphry-Baker, and M. Grätzel, Molecular Wiring of Nanocrystals: NCS-enhanced Cross-surface Charge Transfer in Self-assembled Ru-complex Monolayer on Mesoscopic Oxide Films. J. Am. Chem. Soc., 128, 4446 (2006).

R. O’Hayre, M. Nanu, J. Schoonman, A. Goossens, Q. Wang, and M. Grätzel, The Influence of TiO2 Particle Size in TiO2/CuInS2 Nanocomposite Solar Cells. Adv. Funct. Mater., 16, 1566 (2006).

Teaching:
Thermodynamics and Phase Diagrams (MLE2102)
Photovoltaics and Photovoltaic Materials (MLE4208)