Changing the rules: UNSW breakthrough opens door to silicon cells beyond 30% efficiency with singlet fission

A team from UNSW Sydney has published a major advance that could unlock a new generation of high-efficiency silicon solar cells – using singlet fission.

The researchers demonstrate, for the first time, that a new class of stable organic molecules can be integrated with silicon to boost efficiency, while reducing heat and extending panel lifetime.

Most solar cells today convert one absorbed photon into a single electron-hole pair. Singlet fission changes the rules: it allows one high-energy photon to generate two excited electron-hole pairs, effectively doubling the electrical yield from the bluest part of the solar spectrum. Theoretical models suggest that adding a singlet fission layer could improve silicon solar cell efficiency by more than 10%¹.

The use of singlet fission molecules on silicon solar cells has the potential to increase energy conversion efficiencies from 29% to 42%.

Until now, demonstrations of singlet fission with silicon had relied on tetracene, a molecule that is unstable in air and not suitable for commercial use. In their paper Singlet Fission c-Si Solar Cells: Beyond Tetracene², the UNSW team reports success using a robust, photostable alternative, dipyrrolonaphthyridinedione (DPND), that is compatible with crystalline silicon photovoltaics, and scalable.

Lead researcher and UNSW SPREE's Head of School, Professor Ned Ekins-Daukes said, “Crucially, we’ve developed a practical pathway to higher output silicon solar cells, without the cost and complexity of tandems, that industry can now trial.”

DPND, a relatively stable dye, has been used for the first time to augment the number of carriers in silicon for solar cells.

Why it matters

The commercial implications are far-reaching, as the team outlined in their recent editorial, Singlet Fission Provides a Scalable Pathway to High Efficiency Silicon Photovoltaics³.

A tandem, but not really – Most research into the next generation of silicon solar cells is on tandem devices that have at least two junctions, requiring a redesign of the entire cell architecture. In contrast, singlet fission on silicon solar cells can be built upon silicon technologies with minimal changes to the silicon architecture.

Higher power from the same footprint – Silicon modules today typically achieve 20–25% efficiency. Singlet fission could lift that figure beyond 30%, meaning fewer panels are needed for the same energy output, lowering balance-of-system costs and opening applications in space-constrained rooftops, electric vehicles, and building-integrated photovoltaics.

Cooler operation, longer life – By harvesting energy that would otherwise turn to heat, singlet fission reduces silicon cell operating temperatures. Lab and modelling studies suggest panels could run 2.4 °C cooler, extending lifetime by around 4.5 years. This lowers replacement costs and increases the value of long-term power purchase agreements.

Supported by ARENA and premier industry partners

This research is backed by ARENA through its Transformative Research Accelerating Commercialisation (TRAC008) program, with A$4.8 million in funding to help bridge the gap between lab demonstrations and commercial adoption.

Industry partners include a roster of tier-1 manufacturers including Jinko Solar, JA Solar, LONGi, Canadian Solar, DASolar, Leadmicro, Jollywood and Xinhao New Energy, underlining strong global interest in the technology.

 CI Dr Jessica Yajie Jiang (UNSW) said, “For manufacturers, the attraction is clear: more energy from the same module materials, plus cooler running that extends lifetime.”

A two-decade track record of global leadership

The UNSW breakthrough builds on nearly 20 years of collaboration between three of the lead researchers: Professors Tim Schmidt and Ned Ekins-Daukes, and Assoc. Prof. Murad Tayebjee. Schmidt is a leading expert on the science of molecular singlet fission while Ekins-Daukes is an expert in high efficiency photovoltaics, and Tayebjee is an award-winning physical chemist and solar PV engineer.

Recent work by the team, published in Nature Chemistry in 2024 ⁴, showed how the photoluminescence emitted from the singlet fission is linked to the underlying molecular process. This means the light emitted can be used to monitor the process, creating a powerful diagnostic for materials development and quality control in PV manufacturing.

Assoc. Prof. Murad Tayebjee (UNSW) said, “We can now read the light signatures of singlet fission with unprecedented clarity. This opens the door to discovering and optimising a wide range of new materials that could one day boost the efficiency of silicon solar cells.”

What’s next

The UNSW team have filed patent protection and is now working with partners to scale production of DPND molecules and prepare silicon-integrated stacks for pilot-line trials. With strong ARENA support and an international consortium of industry partners, this discovery represents a decisive step towards commercialisation.

As Dr Jiang notes: “We’re now moving from elegant science to practical solar products — and the impact for industry, investors and the environment could be profound.”

Australian researchers are at the forefront of singlet fission research in solar technologies

This breakthrough complements important contributions from other Australian researchers. Supported by ACAP,  a team from ANU, the University of Queensland, and the University of Melbourne recently reported molecular engineering strategies to tune energy levels for silicon-matched singlet fission, published in Advanced Optical Materials in 2023: Toward Silicon-Matched Singlet Fission: Energy-Level Modifications Through Steric Twisting of Organic Semiconductors⁵. Their work highlights pathways for designing new organic semiconductors that can deliver the right energy levels for efficient triplet harvesting in silicon.

Together, these efforts confirm Australia’s position at the forefront of global singlet fission research and its application to next-generation solar technologies.

Explainer: How does singlet fission improve the efficiency of silicon solar cells?            

Photons from sunlight that are within silicon’s bandgap are absorbed and generate one excited electron-hole pair per photon. Photons below silicon’s bandgap are not absorbed and do not generate electrons. High energy photons above silicon’s bandgap (blue and green wavelengths) are absorbed and create one electron but lose excess energy as heat i.e. thermalisation loss.

When a singlet fission material is layered over a silicon cell, it captures the high energy photons and splits it into two excitons that match silicon’s bandgap, and each form an electron-hole pair. This doubles the electrical yield from the blue, high energy photons, and reduced the heat generation.

References

1. Thermodynamic Limit of Exciton Fission Solar Cell Efficiency, Murad J. Y. Tayebjee, Angus A. Gray-Weale, and Timothy W. Schmidt, The Journal of Physical Chemistry Letters 2012 3 (19), 2749-2754, https://doi.org/10.1021/jz301069u 
   

2. Singlet Fission c-Si Solar Cells: Beyond Tetracene, Alexander J. Baldacchino, Matthew W. Brett, Ben P. Carwithen, Shona McNab, Jingnan Tong, Victor Y. Zhang, Nathan L. Chang, Alison Ciesla, Damon M. de Clercq, Simona S. Capomolla, Miles I. Collins, Jessica Yajie Jiang, Munavvar F. M. Kavungathodi, Alvin Mo, Phoebe M. Pearce, Bram Hoex, Dane R. McCamey, Michael P. Nielsen, Jonathon E. Beves, Nicholas J. Ekins-Daukes, Timothy W. Schmidt, and Murad J. Y. Tayebjee, ACS Energy Letters 2025 10 (9), 4596-4602, https://doi.org/10.1021/acsenergylett.5c01930

3. Singlet Fission Provides a Scalable Pathway to High Efficiency Silicon Photovoltaics, Marc A. Baldo, Nicholas J. Ekins-Daukes, Jessica Yajie Jiang, Phoebe M. Pearce, Timothy W. Schmidt, and Murad J. Y. Tayebjee, ACS Energy Letters 0, 10, https://doi.org/10.1021/acsenergylett.5c01944 

4. Magnetic fields reveal signatures of triplet-pair multi-exciton photoluminescence in singlet fission, Feng, J., Hosseinabadi, P., de Clercq, D.M. et al. , Nat. Chem. 16, 1861–1867 (2024). https://doi.org/10.1038/s41557-024-01591-0 
   

5. Toward Silicon-Matched Singlet Fission: Energy-Level Modifications Through Steric Twisting of Organic Semiconductors, C. J. Lee, A. Sharma, N. A. Panjwani, I. M. Etchells, E. M. Gholizadeh, J. M. White, P. E. Shaw, P. L. Burn, J. Behrends, A. Rao, D. Jones, . Adv. Optical Mater. 2024, 12, 2301539. https://doi.org/10.1002/adom.202301539