PhD on Two-dimensional photovoltaic devices with plasmonically enhanced efficiency
Length of Award: 4 years from September 2015
Value: Tuition fee, stipend of £13,863, and travel funding of £1,500 (UK and EU students) Tuition fee only (non-EU students).
Supervisors: Dr. Monica Craciun and Prof Saverio Russo
The University of Exeter is a top 10 UK university, and a member of the elite Russell Group of institutions. It was named University of the Year in The Sunday Times University Guide 2013 and is in 8th place in The Sunday Times league table for 2014. Recent capital projects to the value of GBP 350 million across the University ensure a truly world-class research and teaching environment and inspirational location to work and live.
The EPSRC Centre for Doctoral Training in Metamaterials (XM2) is hosted by the University of Exeter, and located entirely in the Engineering and Physics buildings on the Streatham Campus. We recruited 18 excellent students in our first year and are admitting another 14-18 PhD students in September 2015.
Project Overview
Heterostructures based on two-dimensional (2D) materials such as graphene and transition metal dichalcogenides (TMDCs) have created a new paradigm in optoelectronics due to their potential for novel flexible and transparent applications. For example, owing to the strong light-matter interactions in TMDCs, graphene/TMDCs/graphene solar cells could reach an extrinsic quantum efficiency of 30% [ Science 340, 1311 (2013)]- up to three orders of magnitude higher than the most efficient flexible organic solar cells – paving the way for next generation photovoltaics. So far optoelectronic devices based on 2D materials have been created by mechanical exfoliation of monolayers from their bulk counterpart. However, growth of large-scale, high-quality 2D heterostructures is required for the practical realization of 2D photovoltaics and for enabling a new generation of ubiquitous optoelectronics in walls, windows or fabrics. Furthermore, higher efficiency is required for the 2D photovoltaic devices to make them competitive with current inorganic solar cells. The realization of large-scale, high-quality and high-efficiency 2D photovoltaics is exactly the aim of this project.
The PhD student will pioneer a new generation of photovoltaic devices based on heterostructures of graphene and TMDC grown by Chemical Vapor Deposition (CVD). The project will involve investigation of both vertical and lateral p-n junctions of TMDCs as active layers and graphene as electrodes. To enhance the already high efficiency of these devices (ensured by the peculiar band structure of TMDC) light absorption in the active layer will be increased through the use of plasmonic nanostructures. Specifically, periodically patterned metallic nanostructures, which offer a controllable approach to enhance the optical absorption of the active light-harvesting layers, will be created using our stat-of the art electron-beam lithography (with resolution down to 10nm). The plasmonic nanostructures form a broadband light-harvesting metamaterial that will be used to generate evanescent photons in near-field under light illumination. Such near-field photons will be absorbed in the active layer and will lead to enhanced efficiency of the device due to the additional photo-carriers that they will generate.
Application Details:
Please, send your academic CV to Dr. Monica Craciun (m.f.craciun@exeter.ac.uk) before January 25th, 2015. Salary: £13,863.00 /year
