Cambridge Photon Technology Raises £1.56M to Make Solar Panels 15% More Efficient With a Drop-In Photon Multiplier

November 6, 2025

Cambridge Photon Technology (CPT), the deep-tech spinout from the University of Cambridge, raised £1.56 million in a pre-Series A funding round in November 2025. The round combines £926,000 in equity investment from Cambridge Enterprise Ventures, Spectrum Impact, Tybourne Capital, Providence Investment Company, and SourceSquared, with a £630,000 grant from Innovate UK’s Investor Partnerships: Clean Energy and Climate Technologies programme. The capital will fund expansion of CPT’s R&D operations in Cambridge, acceleration of material testing with global industry partners, and preparation for a larger Series A raise ahead of pilot deployment. CPT aims to bring its first commercial product to market by 2028.

Solar photovoltaics have transformed the global energy landscape over the past two decades. The cost of silicon solar panels has fallen by more than 90% since 2010, making solar the cheapest source of electricity generation in history. But silicon’s physics imposes a ceiling on how much of the sun’s light it can convert to electricity. Theoretical analysis establishes the Shockley-Queisser limit at approximately 33% for single-junction silicon cells; practical commercial panels typically achieve 20-24%. One of the key losses is the fate of high-energy, short-wavelength photons: their energy exceeds what silicon can usefully absorb, so the excess is released as heat rather than electricity. This “spectral loss” represents one of the most significant efficiency gaps in conventional silicon PV.

CPT’s patented photon-multiplier technology directly addresses this loss through a process called photon multiplication: high-energy photons — those in the blue and ultraviolet range — are absorbed by CPT’s material and re-emitted as two infrared photons, each at an energy level that silicon can efficiently absorb and convert to electricity. By converting each wasted high-energy photon into two usable ones, the technology can increase the energy output of a standard silicon panel by up to 15% without any change to the module’s design, architecture, or manufacturing process. The material is applied as a coating that integrates into standard solar module assembly, requiring no capital-intensive retooling by manufacturers. CPT describes this as a “drop-in” solution, meaning that any solar panel manufacturer can adopt it by adding a coating step to existing production lines. This compatibility with standard infrastructure makes it commercially viable in a way that competing approaches — which require new cell architectures, tandem structures, or novel manufacturing equipment — cannot claim.

The significance of a 15% efficiency gain applied at the module level is substantial. Global solar capacity is currently measured in terawatts and growing rapidly. A 15% output increase applied across the installed base would represent an enormous increment of clean electricity generation without requiring additional land, materials, or capital for new installations. For new projects, the same panel area would generate more electricity, improving the economics of every solar project in the world.

Cambridge Enterprise Ventures’ Chris Gibbs described CPT as exemplifying “the kind of transformative innovation needed to accelerate the global transition to sustainable energy,” and noted the firm’s pride in having supported the company since its earliest stage. Innovate UK’s participation through its Investor Partnerships programme — which requires aligned private investment as a condition of grant funding — adds both financial support and an important signal of the UK government’s confidence in CPT’s technology readiness.

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