Transformational concepts in window electrode design for emerging thin film photovoltaics

Lead Research Organisation: University of Warwick
Department Name: Chemistry

Abstract

Photovoltaic (PV) devices convert sunlight directly into electricity and form an increasingly important part of the global renewable energy landscape. Today's PVs are based on conventional semiconductors which are energy-intensive to produce and restricted to rigid flat plate designs. The next generation of PVs will be based on very thin films of semiconductors that can be processed from solution at low temperature, which opens the door to exceptionally low cost manufacturing processes and new application areas not available to today's rigid flat plate PVs, particularly in the areas of transportation and buildings integration. The emerging generation of thin film PVs also offer exceptional carbon dioxide mitigation potential because they are expected to return the energy used in their fabrication within weeks of installation. However, this potential can only be achieved if the electrode that allows light into these devices is low cost and flexible, and at present no electrode technology meets both the cost constraint and technical specifications needed. This proposal seeks to address this complex and inherently interdisciplinary challenge using three new and distinct approaches based on the use of nano-structured films of metal less than 100 metal atoms in thickness. The first approach focuses on the development of a low cost, large area method for the fabrication of metal film electrodes with a dense array of holes through which light can pass unhindered. The second approach seeks to determine design rules for a new type of 'light-catching' electrode that interacts strongly with the incoming light, trapping and concentrating it at the interface with the semiconductor layer inside the device responsible for converting the light into electricity. The final approach is based on combining ultra-thin metal films with ultra-thin films of transparent semiconductor materials to achieve double layer electrodes with exceptional properties resulting from spontaneous intermixing of the two thin solid films. The UK is a global leader in the development of next generation PVs with a growing number of companies now focused on bringing them to market, and so the outputs of the proposed programme of research has strong potential to directly increase the economic competitiveness of the UK in this young sector and would help to address the now time critical challenge of climate change due to global warming.

Planned Impact

The emergence of a low cost photovoltaic (PV) technology suitable for transport applications and buildings integration would have far-reaching societal and environmental benefits: (i) by providing a source of electricity for the 1.3 billion people currently without access to grid electricity, many of whom live in buildings not capable of supporting conventional PVs.; (ii) by helping to increase the security of electricity supply.; and (iii) by reducing reliance on fossil fuels, thereby helping to combat global warming and climate change. The emerging generation of thin film photovoltaics (e-TFPVs) offer a path to a dramatic reduction in the cost of manufacturing PVs, and their low thickness renders them light weight, low profile and flexible, which opens the door to applications in vehicles and building facades not available to conventional flat plate PVs. e-TFPVs also offer exceptional carbon dioxide mitigation potential because they are expected to return the energy used in their fabrication within weeks of installation.
The UK is a global leader in the development of e-TFPVs, with an intensive research effort in this area in a number of its leading universities, and a growing number of enterprises dedicated to bringing e-TFPVs to the market, including Dyesol UK, SolarPress, Oxford PV and Eight19. Maintaining this position, at a time when these technologies are on the verge of commercialisation, is important to the UK economy because it sets the scene for the UK to firmly establish an industry base in this sector. The aforementioned companies stand to benefit directly from the outputs of this proposal because: (i) it is widely recognised that the full commercial potential of e-TFPVs can only be realised if the electrode that allows light into these devices is low cost and flexible, and the primary output of this project would be a window electrode technology matched to the needs of e-TFPVs.; (ii) the specialist high level skills and experience of the researchers involved with this project would represent a potential source of skilled staff at the project end. UK based companies not directly engaged with e-TFPV commercialisation but who are well positioned to benefit from the project outputs include those that develop and/or manufacture non-PV based devices that require a transparent electrode, including displays, sensors and emerging semi-transparent electronic applications. These companies would benefit if the cost, form or functionality of their product is improved by switching to the transparent electrode technology developed in this project. UK based examples include Cambridge Display Technology (low energy solid state lighting), Molecular Vision (chemical sensing), PolyPhotonix (healthcare) and FlexEnable (flexible electronics). Companies that produce glass coated with optically thin metal films for building and transport applications, such as low emissivity glass, smart glass and anti-reflective coatings would also stand to benefit, since the new method of fabricating patterned metal films over large areas developed in this project may impart a cost advantage, or improved properties as compared to existing methods. Companies in this space include Pilkington glass, Corning, Saint Gobain and Tata. Companies that develop and manufacture machines and processes for depositing and patterning metal films on flexible substrates would also be beneficiaries if they choose to become involved with translating the outputs of the project from the laboratory to end users (e.g. e-TFPV manufacturers). These include Bobst Manchester and the Centre for Process Innovation (CPI) in Sedgefield. The strategy for ensuring that these potential beneficiaries are able to engage with the outputs of this project includes the establishment of an industrial advisory board and is detailed in the Pathways to Impact Plan.

Publications

10 25 50
 
Description The invention of a way to pattern silver, copper and gold films without chemical etching.
Exploitation Route For a variety of applications (in particular solar energy and sensors)
Sectors Electronics

Energy

Healthcare

URL https://warwick.ac.uk/newsandevents/pressreleases/greener_faster_and
 
Description Development of a high performance laminated transparent top-electrode for emerging thin-film photovoltaics
Amount £461,387 (GBP)
Funding ID EP/V002023/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 03/2021 
End 09/2024
 
Description Guest at British Science Festival - interview in front of audience 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Invited guest 2019 British Science Festival: 'Join the conversation between Serena Bashal from the UK Youth Climate Coalition and Ross Hatton a renewable energy researcher from the University of Warwick, as they look at the rise in youth-led climate activism and what science is doing to tackle the challenge we face.' Through this event I contributed to inspiring the bright minds of the future to see the opportunities the seemingly overwhelming challenge of global warming presents.
Year(s) Of Engagement Activity 2019
 
Description Hatton Group hosted an outreach event for 35 pupils from Our Lady's Catholic Primary School in Princethorpe on 22nd September 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact The Hatton Group hosted an outreach event for 35 pupils (10-11 years old) from Our Lady's Catholic Primary School in Princethorpe on 22nd September 2107, which formed part of the University wide Solarfest outreach event. The activity hosted by the Hatton group comprised a laboratory workshop during which the children were introduced to making electricity from sunlight using berry juice. This was followed by a series of short talks (over lunch) during which they learnt about the international nature of scientific research: Specifically they learnt about, and met people from, South Korea, Sri Lanka and Italy since these are the overseas nationalities represented in my group. They also learnt that scientific research is a career for both women and men. The school reported increased interest in science.
Year(s) Of Engagement Activity 2017
URL https://warwick.ac.uk/fac/sci/chemistry/research/hatton/hattongroup/outreach/
 
Description Interview for national news article (BBC News - Business) 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact I was interviewed by the BBC journalist Padraig Belton about developments in emerging thin film photovoltaics for the article: 'Seeing the light: How India is embracing solar power' (9th May 2017).
Year(s) Of Engagement Activity 2017
URL http://www.bbc.co.uk/news/business-39844446
 
Description School outreach event 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact The Hatton Group hosted a series of outreach events for local primary school children (9-11 years old) from two regional schools. Each event involved a laboratory workshop during which the children made simple dye sensitized solar cells using berry juice, followed by a series of short talks (over lunch) during which they learnt about the international nature of scientific research and that scientific research is a career for both women and men.
Year(s) Of Engagement Activity 2017,2019,2020
URL https://warwick.ac.uk/fac/sci/chemistry/research/hatton/hattongroup/outreach/