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Durham University

Institute of Medieval and Early Modern Studies (IMEMS)

Staff and Governance

Core Staff

The day-to-day running of IMEMS is the responsibility of the Core Executive Committee, comprising the Director and Associate Directors and the Administrator. 

Publication details for Prof. Andrew Beeby

King, S.M., Al-Attar, H.A., Evans, R.J., Congreve, A., Beeby, A. & Monkman, A.R. (2006). The use of substituted iridium complexes in doped polymer electrophosphorescent devices The influence of triplet transfer and other factors on enhancing device performance. Advanced functional materials 16(8): 1043-1050.

Author(s) from Durham


The problem of phosphorescence quenching by the host polymer of a dopant in a polyfluorene-based electrophosphorescent device has been extensively studied. This paper concentrates on reduction of the rate of triplet-energy transfer from the dopant to the host by making inert t-butyl substitutions to the ligands of the well-understood fac-trisphenylpyridine iridium phosphorescent dopant. These substitutions introduce steric bulk to the dopant that approximately halves the rate of energy transfer compared to the unsubstituted dopant, and a concomitant increase in device performance is observed. This is attributed to the strong distance dependence of the Dexter-type energy transfer involved, the steric bulk of the t-butyl groups effectively preventing the energy transfer from emissive dopant to the host. In addition, through the use of specific substitutions on either the pyridyl or phenyl ring, the pathway of the energy transfer has been identified as being through the pyridyl ring of the ligand. Employing this technique of steric prevention of the triplet-energy transfer to the host reduces the need for development of hosts with a high triplet level for electrophosphorescent devices.

Full Executive Committee

Our Full Executive Committee is made up of the Core Executive Committee, listed above, plus a number of executive members including:

International Advisory Board

We are extremely fortunate to have be able to call on the help and guidance of colleagues from around the world who help to shape and guide our direction, strategy and international reach. Our current Advisory Board members are: