Singlet Fission Photon Multipliers - Adding Efficiency to Silicon Solar Cells
Lead Research Organisation:
University of Cambridge
Department Name: Physics
Abstract
Solar energy can make a major contribution to global energy supply, but for this renewable energy source to make a major impact it will need to compete on cost with conventional sources of energy. Silicon solar cells are the incumbent photovoltaic technology, and have benefited from huge reductions in manufacturing costs over the last 5-8 years. Now that the module cost is no longer the largest component of the installed system cost, further reductions in the cost per installed Watt require increases in the cell efficiency. However, single-junction cells such as silicon are fundamentally limited by the fact that the energy of the solar spectrum in excess of the semiconductor bandgap energy is lost as heat.
We aim to develop a simple active film that can be applied to the front surface of a silicon (or any other) solar cell that will increase the cell efficiency by up to 4% (e.g. from 20% to 24%). We will do this by capturing the high-energy photons from the solar spectrum and converting them to two lower-energy photons that can be absorbed in the solar cell without energy losses to heat. This will be achieved using the process of singlet exciton fission which occurs in certain organic materials, converting the spin-0 singlet state produced by photon absorption into two spin-1 triplet states. We have very recently demonstrated that it is possible to transfer these non-emissive triplet states onto inorganic semiconductor nanoparticles, which can then efficiently emit photons that could be absorbed by an underlying solar cell.
In this project, we will optimise, engineer and demonstrate photon multiplier films based on the approach described above, providing a low-cost efficiency enhancement for silicon solar cells that can be implemented without re-engineering of the electrical structure of the cell.
We aim to develop a simple active film that can be applied to the front surface of a silicon (or any other) solar cell that will increase the cell efficiency by up to 4% (e.g. from 20% to 24%). We will do this by capturing the high-energy photons from the solar spectrum and converting them to two lower-energy photons that can be absorbed in the solar cell without energy losses to heat. This will be achieved using the process of singlet exciton fission which occurs in certain organic materials, converting the spin-0 singlet state produced by photon absorption into two spin-1 triplet states. We have very recently demonstrated that it is possible to transfer these non-emissive triplet states onto inorganic semiconductor nanoparticles, which can then efficiently emit photons that could be absorbed by an underlying solar cell.
In this project, we will optimise, engineer and demonstrate photon multiplier films based on the approach described above, providing a low-cost efficiency enhancement for silicon solar cells that can be implemented without re-engineering of the electrical structure of the cell.
Planned Impact
If this proposal achieves its ambitious targets then on a 5-10 year timescale we will see a fission photon multiplier film on every solar cell in the world. The value of a 10% relative increase in efficiency would amount to $10bn for a projected $100bn annual PV market.
Improving the cost-effectiveness of photovoltaic systems will accelerate their deployment, thus bringing global environmental benefits through carbon emissions reduction. At the top of the chain of commercial beneficiaries will be the global photovoltaics industry which will benefit through enhanced sales of high-performance systems. The commerical opportunity within the UK is to capture the added value arising from the fission converter by selling films, materials and/or formulations, or by licensing device structure, materials and process IP into the global PV industry. Further down the supply chain we identify opportunities for materials suppliers, both in the organic and inorganic nanoparticle spheres. We emphasise that we are offering an "add-on" product that will not require redesign of the underlying cell technology or manufacturing process, and that this provides a much more straightforward pathway to impact than for new cell technologies.
Improving the cost-effectiveness of photovoltaic systems will accelerate their deployment, thus bringing global environmental benefits through carbon emissions reduction. At the top of the chain of commercial beneficiaries will be the global photovoltaics industry which will benefit through enhanced sales of high-performance systems. The commerical opportunity within the UK is to capture the added value arising from the fission converter by selling films, materials and/or formulations, or by licensing device structure, materials and process IP into the global PV industry. Further down the supply chain we identify opportunities for materials suppliers, both in the organic and inorganic nanoparticle spheres. We emphasise that we are offering an "add-on" product that will not require redesign of the underlying cell technology or manufacturing process, and that this provides a much more straightforward pathway to impact than for new cell technologies.
Publications
Allardice JR
(2019)
Correction to "Engineering Molecular Ligand Shells on Quantum Dots for Quantitative Harvesting of Triplet Excitons Generated by Singlet Fission".
in Journal of the American Chemical Society
Allardice JR
(2019)
Engineering Molecular Ligand Shells on Quantum Dots for Quantitative Harvesting of Triplet Excitons Generated by Singlet Fission.
in Journal of the American Chemical Society
Alsari M
(2018)
Degradation Kinetics of Inverted Perovskite Solar Cells.
in Scientific reports
Baikie T
(2022)
Thermodynamic Limits of Photon-Multiplier Luminescent Solar Concentrators
in PRX Energy
Chen H
(2018)
Crystal Engineering of Dibenzothiophenothieno[3,2- b ]thiophene (DBTTT) Isomers for Organic Field-Effect Transistors
in Chemistry of Materials
Conaghan PJ
(2018)
Efficient Vacuum-Processed Light-Emitting Diodes Based on Carbene-Metal-Amides.
in Advanced materials (Deerfield Beach, Fla.)
Cossuet T
(2018)
ZnO/CuCrO 2 Core-Shell Nanowire Heterostructures for Self-Powered UV Photodetectors with Fast Response
in Advanced Functional Materials
Davis N
(2019)
Improving the photoluminescence quantum yields of quantum dot films through a donor/acceptor system for near-IR LEDs
in Materials Horizons
Davis NJLK
(2018)
Singlet Fission and Triplet Transfer to PbS Quantum Dots in TIPS-Tetracene Carboxylic Acid Ligands.
in The journal of physical chemistry letters
Fallon K
(2019)
Exploiting Excited-State Aromaticity To Design Highly Stable Singlet Fission Materials
in Journal of the American Chemical Society
Kim VO
(2019)
Singlet exciton fission via an intermolecular charge transfer state in coevaporated pentacene-perfluoropentacene thin films.
in The Journal of chemical physics
Li W
(2017)
Contrasting Effects of Energy Transfer in Determining Efficiency Improvements in Ternary Polymer Solar Cells
in Advanced Functional Materials
Pearson A
(2017)
Silicon phthalocyanines as dopant red emitters for efficient solution processed OLEDs
in Journal of Materials Chemistry C
Pearson A
(2017)
Structure formation and evolution in semiconductor films for perovskite and organic photovoltaics
in Journal of Materials Research
Rao A
(2017)
Harnessing singlet exciton fission to break the Shockley-Queisser limit
in Nature Reviews Materials
Schmidt T
(2018)
All-optical augmentation of solar cells using a combination of up- and downconversion
in Journal of Photonics for Energy
Schnedermann C
(2019)
Ultrafast Tracking of Exciton and Charge Carrier Transport in Optoelectronic Materials on the Nanometer Scale.
in The journal of physical chemistry letters
Schnedermann C
(2019)
A molecular movie of ultrafast singlet fission.
in Nature communications
Thampi A
(2018)
Elucidation of Excitation Energy Dependent Correlated Triplet Pair Formation Pathways in an Endothermic Singlet Fission System.
in Journal of the American Chemical Society
Yang L
(2017)
Conjugated Small Molecule for Efficient Hole Transport in High-Performance p-i-n Type Perovskite Solar Cells
in Advanced Functional Materials
| Description | We have discovered that it is possible to harness triplet excitons generated by the process of singlet fission by attaching fission molecules as ligands on emissive PbS nanoparticles. |
| Exploitation Route | In the development of photon multiplier films to enhance the efficiency of silicon solar cells. |
| Sectors | Energy |
| Description | The singlet fission technology developed in this grant has been transferred to a new start-up, Cambridge Photon Technology. The company is, in collaboration with the University of Cambridge, continuing to improve the performance of photon multiplier films to provide efficiency enhancements in solar cells. It is engaging with potential end users, and has been successful in raising investment to support its research programme and IP portfolio. |
| First Year Of Impact | 2018 |
| Sector | Electronics,Energy |
| Impact Types | Economic |
| Description | Energy Catalyst Round 4 |
| Amount | £232,297 (GBP) |
| Funding ID | 132952 |
| Organisation | Innovate UK |
| Sector | Public |
| Country | United Kingdom |
| Start | 11/2017 |
| End | 10/2018 |
| Description | Materials & Manufacturing Round 2 |
| Amount | £601,670 (GBP) |
| Funding ID | 103757 |
| Organisation | Innovate UK |
| Sector | Public |
| Country | United Kingdom |
| Start | 10/2017 |
| End | 09/2019 |
| Title | Research data supporting "Contrasting effects of energy transfer in determining efficiency improvements in ternary polymer solar cells". |
| Description | GIWAXS data of polymer and polymer:fullerene blend thin films. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2017 |
| Provided To Others? | Yes |
| Title | Research data supporting "Engineering Molecular Ligand Shells on Quantum Dots for Quantitative Harvesting of Triplet Excitons Generated by Singlet Fission" |
| Description | This dataset consists of graphical and tabular data in an Origin file format. The file includes UV-Vis absorption, PLQE, kinetic modelling, transient PL and absorption, steady-state PL and excitation spectra and magnetic field dependent PL measurement data and analysis. Further information about the data collection methods and analysis is available via the journal JACS, at 10.1021/jacs.9b06584. The Origin file "Analysis.opju" contains the data for all plots presented in the paper and SI titled "Engineering Molecular Ligand Shells on Quantum Dots for Quantitative Harvesting of Triplet Excitons Generated by Singlet Fission", along with additional data surrounding the analysis of the presented data. The file is separated into folders sorted by experiment. Figures used in the paper are prefixed with either "Main Fig" or "SI" followed by a brief description of the figure. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2019 |
| Provided To Others? | Yes |
| Title | Research data supporting "Silicon phthalocyanines as dopant red emitters for efficient solution processed OLEDs". |
| Description | Underlying UV-Vis, PL, EL and OLED current-voltage-luminance data for the samples discussed in the main article. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2017 |
| Provided To Others? | Yes |
| Description | Industrial engagment |
| Organisation | Eight19 |
| Country | United Kingdom |
| Sector | Private |
| PI Contribution | Provided materials know-how arising from research programme into industrial partnership for scale-up and development. |
| Collaborator Contribution | Provided scale-up and development pathway. |
| Impact | Innovate UK applications and engagement with cell manufacturers |
| Start Year | 2016 |
| Title | PHOTON MULTIPLIER FILM |
| Description | There is provided a ternary photon multiplier film. The photon multiplier film comprises an organic semiconductor material capable of multiple exciton generation and a luminescent material in a host material, wherein the bandgap of the luminescent material is selected such that the triplet excitons formed as a result from the multiple exciton generation in the organic semiconductor can be energy transferred into the luminescent material. |
| IP Reference | WO2018189527 |
| Protection | Patent application published |
| Year Protection Granted | 2018 |
| Licensed | Yes |
| Impact | Further development of photon multiplier technology |
| Company Name | CAMBRIDGE PHOTON TECHNOLOGY LIMITED |
| Description | Cambridge Photon Technology (CPT) is developing next-generation advanced materials designed to increase the performance of existing silicon solar panels by as much as 15%. The patented photon multiplier material is the only technology of its kind that integrates seamlessly into existing photovoltaic modules without the need to change the production process, meaning manufacturers can realise performance improvements quickly and at scale. The company is a spin-out of the University of Cambridge, and is developing the singlet fission technology initially researched at the Cavendish Laboratory, supported by EPSRC and Innovate UK funding. |
| Year Established | 2019 |
| Impact | The company has attracted investment to support a team of ~4 development scientists. It continues to collaborate closely with the University of Cambridge. |
| Website | https://www.cambridgephoton.com |