Keywords
Thin film solar cells, thin film growth, photovoltaics,
materials characterisation, transparent conducting
oxides, PV devices, combinatorial optimisation,
Transparent Conducting Oxide (TCO), RF sputtering,
Atomic Layer Deposition (ALD)
Expertise
As the sun is our ultimate energy source, it makes sense
to make more of this emissions-free power supply. Our
research specialises in the fabrication of thin film solar
cells and materials, and their advanced characterisation.
We have developed processes for the production of
16.5%
efficient
II-VI
thin film solar cells. This world-class
result has been built on underpinning studies of thin film
growth processes and of the mechanisms that typically
limit the efficiencies of devices.
We also work on transparent conducting oxides (TCOs),
conducting experiments on novel doping techniques for
semiconducting materials and investigations in how to
combine optimally traditional and novel PV materials.
Capabilities and facilities
•
Thin film deposition (RF magnetron sputtering
for II-VI semiconductors, copper chalcogenides
and TCOs)
•
Photovoltaic device measurements (eg J-V and
EQE analysis)
•
Frequency response analysis system (including
thermal admittance spectroscopy and
impedance analysis)
•
Shimadzu Solid Spec UV3700 spectrophotometer
system
•
Clean room facilities for electronics and
semiconductor fabrication
•
Plasma technologies (Opal Plasma ALD reactor)
for atomic layer deposition
•
Advanced transmission electron microscopy
facilities
•
Thin film metrology equipment.
Relevant centres and groups
•
Stephenson Institute for Renewable Energy.
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Buildings account for close to half of the national
energy consumption. Energy-saving glass is a key
material in reducing heat loss from buildings. The
increasing demands to reduce CO
2
emissions,
by using heating fuel more efficiently, is driving
research for the next generation of energy-saving
glass used in double glazing units. Our research
has been developing materials and manufacturing
processes to meet these needs.
We have particular expertise in the development
of transparent conducting oxides (TCO) which are
increasingly used for energy applications such as
energy-saving glass and solar cell technology.
TCOs are frequently used to make the electrical
contacts in photovoltaic cells. They transmit the
solar radiation from the surface of the cell to the
underlying materials that create the electrical
current. Using TCOs rather than metal contacts
helps to make the cells more efficient.
The TCO coatings required to make energy-saving
glass more efficient are made up from thin films of
metal or ceramic. They are so thin that visible light
can pass through, but precious heat energy cannot
escape and is reflected back into the room.
We have been investigating methods of depositing
these ultra-thin films with atomic scale precision
and have expertise in the manufacture of thin
film TCO. In particular we have used atomic layer
deposition to make transparent and conductive thin
films on glass for both energy saving architectural
glazing and as a substrate for PV solar cells.
Energy & Sustainability
71
1.3
Photovoltaics and transparent conductors
Also see:
Energy & Sustainability –
7.
Living in the sustainable built
environment, page 80
