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Hybrid Semiconductors for Third Generation Solar Cells

  • Supervisors:   Prof Russell Howe, University of Aberdeen, Prof Wuzong Zhou, University of St Andrews
  • Sponsoring Company:  SASOL (UK)
  • PhD Student: Eva Beukes
     

One approach to third generation solar cells is hybrid systems comprising quantum dots of narrow band gap semiconductors combined with a wide band gap semiconductor.  Such a hybrid system offers potential for intercepting a wider fraction of the solar spectrum, for multiple exciton generation, and for capture of hot electrons. The performance of such devices is crucially dependent on the efficient transfer of electrons and holes between the two semiconductor phases.

This project aims to investigate electron transfer in hybrid semiconductors using primarily electron spin resonance spectroscopy. This technique can observe (at cryogenic temperatures) the conduction band electrons and valence band holes produced when a semiconductor is irradiated with visible light, and can monitor the transfer and trapping of these charge carriers between different semiconductors. 

The project will prepare nanoclusters of narrow band gap semiconductors such as CdSe, CdS and CdTe supported on TiO2, and examine the effects of cluster size and interface structure on electron transfer. The interface structures will be modelled with single crystal rutile surfaces, using scanning probe microscopy, and optimised materials will then be prepared as thin films for PV evaluation.