Associate Professor CHUA Lay Lay

(Assistant Head – Graduate Programmes)




B.Sc. Computational Chemistry, NUS, 1995; Engineer, then Principal  Engineer, Chartered Semiconductor Manufacturing, 1995-2001; Member of Technical Staff, Bell Laboratories, 2001-2002;  Research Associate, Cavendish Laboratory, University of Cambridge, 2002-2003; Research Fellow, ONDL, Physics, NUS, 2004-2008; Ph.D. Physics, University of Cambridge.

Contact Information 

Office: S7-03-12
Tel: (65)-6516-4834 | Fax: (65)-6779-1691
Email: chmcll@nus.edu.sg | Personal webpage


 

Recognition and Achievements

  • Inaugural Dual University Professorship appointment between NUS and Cambridge (2008)
  • Associate editor for Journal of Materials Chemistry C- Royal Society of Chemistry

Research Interests

My research program focuses on materials and processing development to advance the science and technology of polymer organic semiconductors including organic polymer−graphene or polymer-swcnt hybrids. Several device chemistry aspects that is central to Organic Electronics (light-emitting diodes, solar cells, thermoelectric generators, photodiodes, batteries and sensors, including structure-morphology–property relations and energy-level engineering.

 

Research Highlight

Ref: Tang, C. G.; Nur Syafiqah, M.; Koh, Q-. M.; Zhao, C.; Zaini, J.; Seah, Q-. J.; Cass, M. J.; Humphries, M. J.; Girzzi, I.; Burroughes, J. H.; Png, R-. Q.; Chua, L. L.; Ho, P. K. H., Multivalent anions as universal latent electron donors. Nature, 2019, 573, 519.

The research has demonstrated that multivalent anions, such as oxalate, carbonate and sulfite, can act as powerful latent electron donors, when they are dispersed as small ion clusters in a polymer matrix of suitable conjugate polyelectrolytes. Conjugated polyelectrolytes are polymers with ionic side groups and delocalised electrons in the backbone. Crucially, the mixture can be processed from solution in air, and the anion spontaneously transfers electrons to the polymer host only after drying, thereby serendipitously protecting the material from atmospheric degradation. With the appropriate polyelectrolyte host, work functions as low as 2.4 electron-volts have been attained, overcoming the long-standing conundrum to marry ultralow work function materials with solution processing. The research team has demonstrated the versatility of this discovery by making a variety of high-performance white-light-emitting diodes and organic solar cells using solution-processed electron-injection layers.

Mr Koh Qi-Mian holding solution samples of hole- (left) and electron-injection (right) materials that are ready for solution-processing in ambient to make electrodes for semiconductor devices.

 

Teaching Contributions

  • CM4253 Materials Chemistry 2
  • CM4254 Chemistry of Semiconductors

 

Representative Publications 

  • Tang, C. G.; Nur Syafiqah, M.; Koh, Q-. M.; Zhao, C.; Zaini, J.; Seah, Q-. J.; Cass, M. J.; Humphries, M. J.; Girzzi, I.; Burroughes, J. H.; Png, R-. Q.; Chua, L. L.; Ho, P. K. H., Multivalent anions as universal latent electron donors. Nature, 2019, 573, 519.
  • Kam, F. Y.; Png R. Q.; Ang M. C. Y.; Kumar, P.; Rubi, K.; Mahendiran, R.; Solomeshch, O.; Tessler, N.; Lim, G. K.; Chua, L. L.; Ho, P. K. H. Solution-processed 2-dimensional hole-doped ionic graphene compound, Mater. Horiz. 2017, 4, 456.
  • Seah, W. L.; Tang, C. G.; Png, R. Q.; Keerthi, V.; Zhao, C.; Guo, H.; Yang, J. G.; Zhou, M.; Ho, P. K. H.; Chua, L. L. "Interface doping for ohmic organic semiconductor contacts using self-aligned polyelectrolyte counterion monolayer" Adv. Funct. Mater. 2017, 1606291.
  • Tang, C. G.; Ang, M. C. Y.; Choo, K. K.; Keerthi, V.; Tan, J. K.; Nur Syafiqah, M.; Kugler, T.; Burroughes, J.H.; Png, R. Q.; Chua, L. L.; Ho, P. K. H. "Doped polymer semiconductors with ultrahigh and ultralow work functions for ohmic contacts", Nature  2016, 539, 536.
  • Png, R. Q.; Ang, M. C. Y; Teo, M. H.; Choo, K. K.; Tang, C. G.; Belaineh, D.; Chua, L. L.; Ho, P. K. H. "Madelung and Hubbard interactions in polaron band model of doped organic semiconductors", Nat. Commun.  2016, 7, 11948.
  • Yang, J. G.; Seah, W. L.; Guo, H.; Tan, J. K.; Zhou, M.; Matsubara, R.; Nakamura, N.; Png, R. Q.; Ho, P. K. H.; Chua, L. L. "Characterization of ohmic contacts in polymer organic field-effect transistors", Org. Electron. 2016, 37, 491.