Assistant Professor TAN Zhi Kuang

photo of Dr Wu Jie B.Sc., Honours 1st Class (2010): National University of Singapore
Ph.D. (2014): University of Cambridge
Postdoc. (2015): University of Cambridge


Contact Information

Department of Chemistry, NUS
3 Science Drive 3
Singapore 117543

Office: S8-05-08
Tel: (65)-6516-6776
Fax: (65)-6779-1691
Email: chmtanz@nus.edu.sg

 

Research Openings

Multiple fully-funded PhD studentships available for Jul/Aug 2017 intake. Students who have experience with nano-material/organic/inorganic synthesis (air-free techniques) or with device fabrication and characterization techniques are preferred. For interested applicants, please contact me at chmtanz@nus.edu.sg , with a CV attached, to discuss about prospective projects.

Details of studentship are available at http://www.nus.edu.sg/admissions/graduate-studies/scholarships-nrs2.php . Applications for part-time/full-time research assistantship positions (starting Jan 2016 or later) are also welcomed.

 

Research Interests

  • Material chemistry and physics of optoelectronic devices, i.e. light-emitting diodes and photovoltaics.
  • New hybrid and organic semiconductors (metal halide perovskites and conjugated molecules/polymers).
  • Spectroscopy and charge dynamics in semiconductors.
  • Nano-materials, structures and quantum dots.

 

Representative Publications

  • Tan, Z.-K., Moghaddam, R. S., Lai, M. L., Docampo, P., Higler, R., Deschler, F., Price, M., Sadhanala, A., Pazos, L. M., Credgington, D., Hanusch, F., Bein, T., Snaith, H. J. and Friend, R. H. Bright light-emitting diodes based on organometal halide perovskite. Nature Nanotechnology 9, 687-692 (2014).
  • Tan, Z.-K., Vaynzof, Y., Credgington, D., Li, C., Casford, M. T. L., Sepe, A., Huettner, S., Nikolka, M., Paulus, F., Yang, L., Sirringhaus, H., Greenham, N. C. and Friend, R. H. In-Situ Switching from Barrier-Limited to Ohmic Anodes for Efficient Organic Optoelectronics. Advanced Functional Materials 24, 3051-3058 (2014).
  • Tan, Z.-K., Johnson, K., Vaynzof, Y., Bakulin, A. A., Chua, L.-L., Ho, P. K. H. and Friend, R. H. Suppressing Recombination in Polymer Photovoltaic Devices via Energy-Level Cascades. Advanced Materials 25, 4131-4138 (2013).
  • Li, G., Tan, Z.-K., Di, D., Lai, M. L., Jiang, L., Lim, J. H.-W., Friend, R. H. and Greenham, N. C. Efficient Light-Emitting Diodes Based on Nanocrystalline Perovskite in a Dielectric Polymer Matrix. Nano Letters 15, 2640-2644 (2015).
  • Wang, J., Wang, N., Jin, Y., Si, J., Tan, Z.-K., Du, H., Cheng, L., Dai, X., Bai, S., He, H., Ye, Z., Lai, M. L., Friend, R. H. and Huang, W. Interfacial Control Toward Efficient and Low-Voltage Perovskite Light-Emitting Diodes. Advanced Materials 27, 2311-2316 (2015).

 

Research Highlights

The manufacturing of traditional semiconductors such as silicon relies on expensive high-temperature and high-vacuum processes, hence rendering them cost-competitive only in small-area or high-value products such as microelectronic chips and sensors. The increasing demands for large-area solid-state lightings, as well as photovoltaics for clean energy generation requires a fundamental breakthrough in semiconductor materials or their fabrication methods. Recently, an organic-inorganic hybrid perovskite semiconductor was discovered to give remarkable performance in photovoltaics and other optoelectronic devices. The key advantages of these perovskites include facile and low-cost solution-processing, as well as easy bandgap tuning.

In 2014, we successfully demonstrated bright electroluminescence in these hybrid perovskites (Tan, Z.-K. et al., Nature Nanotechnology 9, 687), thereby opening up possibilities of their application in large-area multi-coloured displays and lighting. Our group aims to build on this initial success to achieve high-performance perovskite-based light-emitting diodes and photovoltaics through materials engineering as well as fundamental optical and structural investigations.

As perovskite semiconductors possess low exciton binding energy, it is necessary to confine electronic charges within quantum dots or charge-wells for efficient exciton formation and radiative recombination. We chemically synthesize luminescent perovskite nanoparticles and nanorods, and work on surface defect passivation to enhance their luminescence yield. We analyse our new materials using advanced structural techniques such as x-ray diffraction, atomic force microscopy and electron microscopy to investigate their crystallinity and polydispersity. We also use optical spectroscopic techniques to quantify luminescence efficiency and spectral characteristics, which could provide clues towards defect density and the extent of exciton confinement. Successes in the development of this new material class could bring real commercial benefits towards the fledgling large-panel display industry.