Research Projects Supported by
HKU's High Performance Computing Facilities

Department of Chemistry

Researcher:

Eric Chi-Ho Kwok, PhD Student (h0792036@hkusua.hku.hk)
Carmen Ka-Man Chan, Research Associate (ckmchan@hku.hk)
Sue Wai-Han Lam, Research Assistant Professor (chsue@hku.hk)
Keith Man-Chung Wong, Research Assistant Professor (wongmc@hku.hk)
Vivian Wing-Wah Yam, Philip Wong Wilson Wong Professor in Chemistry and Energy (wwyam@hku.hk)

Project Title:

Computational Studies on the Electronic Structures and Photophysical Properties of Transition Metal Alkynyl Complexes

Project Description:

Recently, transition metal alkynyl complexes have been extensively investigated because of the rich photophysical and photochemical properties and their potential applications in organic light-emitting devices (OLEDs) and dye-sensitized solar cells (DSSCs). In the search for promising phosphorescent transition metal complexes as emissive materials for OLED fabrication, one of the requirements is the capability of the materials to exhibit emission in the blue, green, and red region with high phosphorescence quantum yields. On the other hand, in order for transition metal complexes to serve as effective dye sensitizers (light-absorbing dye molecules) for DSSC applications, their capabilities to exhibit intense absorption in the visible part of the spectrum and to form long-lived excited states with energies matching those of the conduction band of the semiconductor substrate are important parameters. A major focus of our research is to provide a rational design and synthetic strategy towards molecular functional materials, which can be aided through the elucidation and prediction of the nature of both the ground and the excited states involved in the absorption and emission of the transition metal alkynyl complexes by using density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations.

Project Duration:

2 years

Project Significance:

These studies will provide a further insight into the electronic structures and excited state properties of the complexes. In addition, the effect of the substituents in the ancillary ligands and the metal center on the origin and energies of the absorption and emission bands will be elucidated. The study provides important guiding principles for the design of phosphorescent metal complexes with a particular emissive color for the OLED application and dye sensitizers with intense visible light absorption and long-lived excited states.

Results Achieved:
  1. Kwok E. C.-H.; Chan, M. Y.; Wong, K. M.-C.; Lam, W. H.; Yam, V. W.-W. "Functionalized Alkynylplatinum(II) Polypyridyl Complexes for Use as Sensitizer in Dye-Sensitized Solar Cells", Chemistry - A European Journal, 2010, accepted.
  2. Wong, K. M.-C.; Lam, W. H.; Zhou, Z.-Y.; Yam, V. W.-W. "A Luminescent Trinuclear Platinum(II) Pt3C2 System with a “Naked” C≡C2- Ligand That Fluctuates amongst Three Unsupported Platinum(II) Moieties", Chemistry - A European Journal, 2008, 14, 10928.
  3. Tam, A. Y.-Y.; Lam, W. H.; Wong, K. M.-C.; Zhu, N.; Yam, V. W.-W. "Luminescent Alkynylplatinum(II) Complexes of 2,6-Bis(N-alkylbenzimidazol-2'-yl)pyridine-Type Ligands with Ready Tunability of the Nature of the Emissive States by Solvent and Electronic Property Modulation", Chemistry - A European Journal, 2008, 14, 4562.
  4. Wong, K. M.-C.; Hung, L.-L.; Lam, W. H.; Zhu, N.; Yam, V. W.-W. "A Class of Luminescent Cyclometalated Alkynylgold(III) Complexes: Synthesis, Characterization, and Electrochemical, Photophysical, and Computational Studies of [Au(C^N^C)(C≡C-R)] (C^N^C = ĸ3C,N,C Bis-cyclometalated 2,6-Diphenylpyridyl)", Journal of the American Chemical Society, 2007, 129, 4350
  5. Yip, S.-K.; Chan, C.-L.; Lam, W. H.; Cheung, K.-K.; Yam, V. W.-W. "Synthesis, Structure and Luminescence Studies of Heterometallic Gold(I)–Copper(I) and –Silver(I) Alkynyl Clusters/Aggregates", Photochemical & Photobiological Sciences, 2007, 6, 365.
  6. Chan, C.-L.; Cheung, K.-L.; Lam, W. H.; Cheng, E. C.-C.; Zhu, N.; Choi, S. W.-K.; Yam, V. W.-W. "Luminescent Molecular Copper(I) Alkynyl Open Cubes: Synthesis, Structural Characterization, Electronic Structure, Photophysics, and Photochemistry", Chemistry - An Asian Journal, 2006, 1-2, 273.
  7. Yip, S.-K.; Lam, W. H.; Zhu, N.; Yam, V. W.-W. "Synthesis, Characterization, Structure and Luminescence Studies of Dinuclear Gold(I) Alkynyls of Bis(diphenylphosphino)alkyl- and aryl-amines", Inorganica Chimica Acta, 2006, 359, 3639.
Remarks on the Use of High Performance Computing Clusters:

Since a large number of DFT and time-dependent DFT calculations for systems containing more than hundreds of atoms in this project are performed, which often require enormous amounts of computer CPU time, memory and disk space, only a high-performance server could handle this kind of calculations. HPC has provided us with the computer facilities and software for performing the quantum chemical calculations.

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