Improved Understanding, Development and Optimisation of Perovskite-based Solar Cells

Lead Research Organisation: Loughborough University
Department Name: Wolfson Sch of Mech, Elec & Manufac Eng

Abstract

Solar is an increasingly important source of power generation. Word-wide installations of new solar modules will exceed 40GW in 2014 with over 1GW that capacity will be installed in the UK. The cost of modules has decreased sharply over the past two years due to over-supply from manufacturers. The cost reduction is now stimulating demand because the cost of energy from solar is now at 'grid parity' in some important regions of the world.

An exciting new type of solar cell based on thin film perovskite light absorbers has been discovered in the UK which has the potential to lower costs still further. The discovery has been made by a team of researchers at Oxford University. The progress they have made with these new devices has been unprecedented and in only two years the Oxford team has achieved conversion efficiencies exceeding 17%. Moreover, the technology has been protected by filing patent applications on the fundamental discoveries.

The Supergen Supersolar Hub comprises eight of the UK's leading University groups (including Oxford) engaged in the development of photovoltaic technologies. The Supergen SuperSolar Hub was quick to recognise the importance of the perovskite development and has already funded complementary research programmes in Hub member and Associate member laboratories through its flexible funding. This proposal for Supergen + funding will increase the scope and ambition of the Hub's perovskite research in modelling, synthesis, process optimization and characterization to boost conversion efficiencies still further and help maintain the UK's leadership position. In addition to the proposed research, proposals are made to increase the Hub's involvement with industry and with leading International laboratories to accelerate progress and lay the foundations for timely exploitation.

Planned Impact

The Supergen SuperSolar Hub addresses the global challenge to produce energy in a clean and efficient manner. This proposal is at the cutting edge and will help to maintain the UK's lead in perovskite Photovoltaics (PV). The SuperSolar Hub has created a PV community in the UK that is inclusive and outward looking. The Hub will continue to catalyse academic-business co-operation to maximize the exploitation of publicly funded research and grow PV related industry and employment

Industrial Impact: The largest Photovoltaic market is utility scale power generation. This market is the "end goal" for the perovskite technology, and the costs play in its favour if the cell efficiency can be translated to module efficiency and if the stability can be improved. Building Integrated Photovoltaics (BIPV) is fast growing sector since there is a drive towards low impact buildings. A large fraction of the cost of solar power is the balance of systems (BOS). BIPV lends itself to tackling the BOS cost, since "solar cladding" can be integrated into the building infrastructure. Commercial buildings are being clad entirely in glass, implying that the additional cost of cladding a building with a solar glazing product removes the cost of the glass substrates. There is a trend towards using "curtain walling" where factory prefabricated cladding units are hung on the steel framework. Prefabricating solar cladding units, with all the wiring and interconnects designed to "click and connect" reduces the installation costs. To deliver BIPV, the photovoltaics should appear similar to existing glass facades. The market is currently supplied by amorphous silicon, which is made semi-transparent by being thin, but results in an unattractive red/orange or brown tint. Most glazed facades are colour neutral. By taking advantage of the spontaneous de-wetting of perovskite films upon crystallization, neutral density attenuation of light can be achieved with controllable levels of transmission. There is also a market for lightweight flexible solar cells, for applications such as power on lightweight commercial roofing, portable electronic power, automotive power and military applications. The perovskite crystal is inherently flexible with a high compressibility and bulk modulus, and efficient perovskite solar cells can be fabricated on flexible substrates. Oxford Photovoltaics Ltd will be a beneficiary of the research many other UK companies are part of a potential supply chain including NSG-Pilkington (TCO coated glass), M-solv Ltd (module interconnect technology),Tata Steel (PV coated cladding),Solar Century (BIPV supplier),Arup Partners (BIPV design),Polysolar (PV curtain walling) and Romag (semi-transparent windows).

Academic impact: The impact made on the academic community by recent developments at Oxford is extremely rare. The external recognition of the breakthrough is exemplified by both the Science and Nature Journals selecting perovskite PV as the breakthrough of the year in 2013. The work is interdisciplinary which broadens the impact to the whole of the science community.

Intellectual property: This project will generate intellectual property for perovskite PV technology with exciting commercial potential.

Training: The work will have impact through the experience in perovskite PV obtained by the postdoctoral researchers undertaking the work. Training in the development of perovskite PV is a major theme in our recently awarded EPSRC CDT in New and Sustainable Photovoltatics and projects will be open to the students in the CDT programme.

Government: The Hub is represented on the DECC UK PV Strategy Group and the PI is co-Chair of its Innovation Task Force. This enables the Hub to influence Government policy and DECC is aware of the opportunities for perovskite PV in BIPV applications.

Publications

10 25 50

 
Description We have designed a broadband anti-reflection coating that increases the current density and efficiency by ~4%.

We have deposited CdS for use as a buffer layer in perovskite solar cells.

We are depositing ITO and other TCO's for use as a transparent contact in perovskite solar cells.
Exploitation Route We have also worked with Oxford Photovoltaics Ltd who are developing commercial applications of perovskite solar cells.
Sectors Energy

 
Description We have worked with Oxford University spin out company, Oxford Photovoltaics Ltd to test alternative n-type layers such as CdS and also supplied transparent back contacts such as ITO, AZO and IZO. This has assisted Oxford PV to achieve a tandem cell perovskite/c-Si structure with 4% additional conversion efficiency than the Si cell. This has huge commercial potential.
First Year Of Impact 2016
Sector Energy
Impact Types Economic

 
Description Member of the Ion and Plasma Surface Interactions committee of the Institute of Physics
Geographic Reach National 
Policy Influence Type Membership of a guideline committee
Impact Promotion of thin films and plasmas to improve industrial manufacturing processes
 
Description A National Thin-Film Cluster Facility for Advanced Functional Materials
Amount £460,998 (GBP)
Funding ID EP/M022900/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 07/2015 
End 08/2020
 
Description organic-inorganic perovskite hybrid tandem solar cells
Amount £696,405 (GBP)
Funding ID EP/M024881/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 04/2015 
End 04/2018
 
Title Dataset for publication: "Modelling dark current decay transients in perovskite solar cells with mobile ions" 
Description Data used to produce the figures in the Journal of Materials Chemistry C publication: "Measurement and modelling of dark current decay transients in perovskite solar cells" 
Type Of Material Database/Collection of data 
Year Produced 2016 
Provided To Others? Yes  
 
Description National Renewable Energy Laboratory 
Organisation U.S. Department of Energy
Department National Renewable Energy Laboratory (NREL)
Country United States 
Sector Public 
PI Contribution National Renewable Energy Laboratory (NREL): NREL is a world leading Research Institution for Renewable Energy. NREL has hosted Nayia Arnou, Sona Ulcina and Luis Infante-Ortego (research students) from CREST for 3 month secondments. The visit by Sona Ulcina led to the development a 17.2% efficient perovskite solar cell using an atmospheric spray process. Several joint publications.
Collaborator Contribution Dr Tim Silverman, a senior scientist at NREL is currently on secondment to CREST for 1 year working on degradation mechanisms in silicon modules.
Impact Publications
Start Year 2014
 
Description OSI-One Step Interconnect for Thin Film PV Modules 
Organisation M-Solv
Country United Kingdom 
Sector Private 
PI Contribution Providing devices for testing the interconnect process. Evaluating the performance and durability of the Interconnects.
Collaborator Contribution Using laser ablation and inkjet printing to interconnect PV cells in a PV module
Impact 3 Publications. M-solv are close to commercialising the OSI process. Our industrial partners are Oxford Photovoltaics Ltd and Dycotec Ltd.
Start Year 2009
 
Title Driftfusion 
Description First official release of Driftfusion. The recent application of lead-halide perovskites as an active layer material in thin film semiconductor devices including solar cells, light emitting diodes (LEDs), and memristors has motivated the development of several new drift-diffusion models that can include the effects of both mobile electronic and ionic charge carriers. Here, we present Driftfusion, a versatile simulation tool built for simulating one-dimensional ordered semiconductor devices with mixed ionic-electronic conducting layers. Driftfusion enables users to simulate devices with virtually any number of layers and with up to four charge carrier species (electrons and holes by default plus up to two ionic species). The time-dependent carrier continuity equations are fully-coupled to Poisson's equation enabling transient optoelectronic device measurement protocols to be simulated. In addition to the material parameters, users have direct access to adapt carrier transport, recombination and generation models as well as the system boundary conditions. Furthermore, a graded-interface approach circumvents the requirement for boundary conditions at material interfaces and enables interface-specific properties, such as high rates of interfacial recombination, to be introduced. 
Type Of Technology Software 
Year Produced 2020 
Open Source License? Yes  
URL https://zenodo.org/record/3670155
 
Title Driftfusion 
Description First official release of Driftfusion. The recent application of lead-halide perovskites as an active layer material in thin film semiconductor devices including solar cells, light emitting diodes (LEDs), and memristors has motivated the development of several new drift-diffusion models that can include the effects of both mobile electronic and ionic charge carriers. Here, we present Driftfusion, a versatile simulation tool built for simulating one-dimensional ordered semiconductor devices with mixed ionic-electronic conducting layers. Driftfusion enables users to simulate devices with virtually any number of layers and with up to four charge carrier species (electrons and holes by default plus up to two ionic species). The time-dependent carrier continuity equations are fully-coupled to Poisson's equation enabling transient optoelectronic device measurement protocols to be simulated. In addition to the material parameters, users have direct access to adapt carrier transport, recombination and generation models as well as the system boundary conditions. Furthermore, a graded-interface approach circumvents the requirement for boundary conditions at material interfaces and enables interface-specific properties, such as high rates of interfacial recombination, to be introduced. 
Type Of Technology Software 
Year Produced 2020 
Open Source License? Yes  
URL https://zenodo.org/record/3670154
 
Description Advances in Photovoltaics 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Meeting on 'Advances in Photovoltaics' held at the Institute of Physics. SuperSolar event with 70 attendees. International invited speakers.
Organiser and Chairman
Year(s) Of Engagement Activity 2015
 
Description Appearance on BBC Breakfast TV 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Appearance on breakfast TV from CREST at Loughborough University publicising latest research discoveries in Photovoltaics. Representative of Oxford Photovoltaics Ltd was also interviewed.
Year(s) Of Engagement Activity 2015
 
Description Feature on Radio 4 Tonight programme. 13th February 2019 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Radio 4 feature on latest developments in Solar
Year(s) Of Engagement Activity 2019
 
Description Member of the Energy commitee of the Institute of Physics 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact The Energy committee of the IOP organises events of interest to the scientific and engineering community concerned with Enery generation and use.
Year(s) Of Engagement Activity 2016,2017,2018,2019
 
Description Member of the IEEE EDS Technical Committee on Photovoltaic devices. 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The IEEE EDS Technical Committee on Photovoltaic devices.is an International body concerned with standards for photovoltaic (solar panel) modules.
Year(s) Of Engagement Activity 2019
 
Description Member of the Ion and Plasma Surface Interactions Group commitee of the Institute of Physics 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact The commitee organises events for academia and industry including the annual 'Advances in Photovoltaics' meeting at the IOP.
Year(s) Of Engagement Activity 2019
 
Description Member of the Solar Commision 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact The Solar Commision has been formed to identify R&D prioriries for solar to stimulate further deployment
Year(s) Of Engagement Activity 2019
 
Description The Big Idea-Investment Opportunities in Solar 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact One day meeting organised in London by SuperSolar and the SOLAR magazine, October 2015. 40 attendees with a Dragon's Den with 4 Venture Capitalists and 8 companies making pitches for funding. Attendees 90% from Industry. Organiser and Chairman.
Year(s) Of Engagement Activity 2015