Key Research Interests and Expertise

The Fielden group is currently working in the following areas:

  • Polyoxometalate-based non-linear optical chromophores and electropolymers. We have recently obtained a series of donor-acceptor chromophores based on polyoxometalates, including systems based on electropolymerizable pyrrole units.  The resulting materials obtain unusually high activity from moderate donor groups and short pi-systems, due to extension of charge transfer onto the POM. We are now working to develop ways of including these materials in films with bulk NLO activity and switchable responses.
  • New catalysts: We are using small, heteroleptic tripodal ligands as a platform to build catalysts for small molecule activation.  The ligands can coordinate a transition metal in a bidentate or tetradentate coordination pocket, while providing a pendant group for introduction of proton or electron relays.  These will allow controlled study of secondary coordination sphere effects. 
  • POM-derivatives as photosensitizers: We are investigating the use of POMs as electron acceptor units in push-pull chromophores.  These are designed to improve the efficiency of p-type dye-sensitized solar cells by retarding recombination of photo-excited electrons to NiO, one of the major sources of inefficiencies in these systems.  
  • New p-type semiconductor nanomaterials: In this project, supported by EU Marie Curie fellowship NanoCuI to Dr. Anil Reddy Marri, we are developing nanoporous copper iodide substrates as a replacement of the NiO p-type semiconductor in the p-type dye-sensitized solar cell (p-DSSC, collaboration with Dr. Andrew Mayes, UEA and Dr Elizabeth Gibson, Newcastle). p-DSSCs, in combination with conventional n-type DSSCs, could be used to make tandem DSSCs with better spectral coverage (light absorption at both electrodes) and photovoltage. However, at present p-DSSCs do not perform well enough to realise this promise, because the conductivity of the NiO substrate is poor. Gamma-CuI has an intrinsically much higher conductivity than NiO, so could produce much better devices, but the high surface area nanoporous electrodes needed for efficient dye sensitization do not yet exist. We are using chemical and electrochemical deposition methods to develop them.

Research Group Membership

Current Group Membership: Kevin Vincent (PDRA), Phil Spence, PhD student (joint BBSRC project with Zoë Waller, Pharmacy), Bethany Hood (PhD student), Sarah Alshehri (PhD student), Charles James (PhD student); plus undergraduate project students Jonas Konig-Hajji (MChem), Chloe Jordan (MChem) and Radoslav Raychev (BSc).

Fielden Group Autumn 2018

 

 

Fielden and Wright Groups, August 2017

 The Fielden and Wright Groups, August 2017

 From left to right: Farhana Haque (PhD, JAW), Trevor Simmons (PDRA, JAW), John Fielden, Joseph Wright, Anil Reddy Marri (Marie Sklodowska Curie Fellow, JF, 2015-17)

The Fielden Group, February 2015

From left to right: Simon Child, John Fielden, Natalia Sanchez Moreno, David Miko, Phil Spence, Hani El-Moll, Ahmed Al-Yasari

From left to right: Simon Child, John Fielden, Natalia Sanchez Moreno, David Miko, Phil Spence, Hani El-Moll, Ahmed Al-Yasari

And among the Ziggurats...

Fielden group outside the UEA Ziggurat buildings

Fielden group outside the UEA Ziggurat buildings

 

 

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