University of Otago, New Zealand


Te Tari Hua-Ruanuku

Gordon Group Researchers

Penny Walsh
Spectroscopy and computational chemistry of dppz complexes and porphyrins

Penny submitted her thesis in 2007 and was a recipient of the Sciences Divisional List of Exceptional PhD theses ( She currently works for the Patent Office (IPONZ) in Wellington

Complexes of dipyrido[3,2-a:2',3'-c]phenazine (dppz) derivatives are useful as components in organic light emitting devices (OLEDs). Density functional theory (DFT) calculations are useful models of complexes of dppz derivatives. Calculated Raman spectra give good agreement with experimental Raman spectra, indicating the validity of the calculations and their usefulness in predicting molecular orbitals and their energy levels. This can lead to rational design of OLED components.

Picture of operating OLED

Another class of molecules which has optoelectronic applications is the porphyrins. Recent advances in porphyrin design by collaborators at Massey University (Nazeeruddin, Md. K. et al, Langmuir (2004), 20, 6514) have produced a porphyrin which gives an overall conversion efficiency of 4.8%, making it the most efficient metalloporphyrin sensitizer yet reported. The use of computational chemistry aided by vibrational spectroscopy to study these molecules, may provide insight into their electronic processes. Improvements in design may lead to solar cell dyes with increasing efficiency.


Images of ligands and complexes from DFT calculations