Associate Professor XU Qing-Hua

B.Sc., Zhejiang Univ.; M.Sc., Peking University and University of Chicago; Ph.D., UC Berkeley; Postdoctoral, Stanford and University of California Santa Barbara.

Contact Information

Office: S8-02-05C
Tel: (65)-6516-7880 | Fax: (65)-6779-1691


ORCID: 0000-0002-4153-0767
ResearcherID: B-1478-2013


Recognition and Achievements

  • Young Scientist Award, Faculty of Science, NUS 2008


Research Interests

We are mainly interested in development of various light based applications, such as sensing, imaging, photo-sensitization and optoelectronics using nano-materials and organic/polymer materials, as well as investigation of the underlying fundamental mechanisms and photophysical processes using various novel optical spectroscopy and imaging techniques to understand their working principles, which provide insights for device design of better performance. Specific foci are:

  •  Nanophotonics, plasmonics, bophotonics and optoelectronics
  •  Optical spectroscopy and imaging


Research Highlight

Our group recently found that aggregation of noble metal nanoparticles resulted in significantly enhanced two-photon photoluminescence. The enhancement factor reached up to a few hundreds of times in solution and five orders of magnitude on the single particle level. This phenomenon has been further utilized to develop various applications in two-photon sensing, imaging, and phototherapy. Ultrafast time-resolved spectroscopy and single particle spectroscopy have been performed to understand the underlying enhancement mechanisms.


Teaching Contributions

  • CM5232 Topics in Chemical Kinetics
  • CM5237 Advanced Optical Spectroscopy and Imaging


Representative Publications 

  • Yuan, P. Y.; Ding, X.; Guan, Z. P.; Gao, N. Y.; Ma, R.; Jiang, X. F.; Yang, Y. Y.; Xu, Q. H. Plasmon-Coupled Gold Nanospheres for Two-Photon Imaging and Photoantibacterial Activity. Adv. Healthc. Mater. 2015, 4, 674-678.
  • Shen, X. Q.; Li, S.; Li, L.; Yao, S. Q.; Xu, Q. H. Highly Efficient, Conjugated-Polymer-Based Nano-Photosensitizers for Selectively Targeted Two-Photon Photodynamic Therapy and Imaging of Cancer Cells. Chem. Eur. J. 2015, 21, 2214-2221.
  • Gao, N. Y. et al. Shape-Dependent Two-Photon Photoluminescence of Single Gold Nanoparticles. J. Phys. Chem. C. 2014, 118, 13904-13911.
  • Yuan, P. Y.; Ma, R. Z.; Guan, Z. P.; Gao, N. Y.; Xu, Q. H. Tuning Two-Photon Photoluminescence of Gold Nanoparticle Aggregates with DNA and Its Application as Turn-on Photoluminescence Probe for DNA Sequence Detection. ACS Appl. Mater. Interf. 2014, 6, 13149-13156.
  • Zhao, T. T. et al. Gold Nanorod Enhanced Two-Photon Excitation Fluorescence of Photosensitizers for Two-Photon Imaging and Photodynamic Therapy. ACS Appl. Mater. Interf. 2014, 6, 2700-2708.
  • Guan, Z. P.; Gao, N. Y.; Jiang, X. F.; Yuan, P. Y.; Han, F.; Xu, Q. H. Huge Enhancement in Two-Photon Photoluminescence of Au Nanoparticle Clusters Revealed by Single-Particle Spectroscopy. J. Am. Chem. Soc. 2013, 135, 7272-7277.
  • Fang, C. H.; Lee, Y. H.; Shao, L.; Jiang, R. B.; Wang, J. F.; Xu, Q. H. Correlating the Plasmonic and Structural Evolutions during the Sulfidation of Silver Nanocubes. ACS Nano 2013, 7, 9354-9365.