Tech breakthrough uses ‘wasted sunlight’ to improve solar panel efficiency

• CPT can boost solar efficiency by 15% by using ‘wasted sunlight’
• Average solar energy efficiency is about 22%
• Company hopes to have new technology on market by 2028

Cambridge Photon Technology (CPT), a deep-tech spin out of Cambridge University, has developed and patented solar technology that it says can help silicon panels generate 15% more power by making use of ‘wasted sunlight’. 

In a statement, CPT said its photon-multiplier technology fits into standard solar modules without any expensive changes to the panel system to make use of sunlight that it otherwise would go to waste. The company said this offers “one of the most practical routes” to increasing global solar panel efficiency. 

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As solar panel efficiency rates are around 22%-25%, any new technology that improves the average PV system’s output will help meet solar energy demand.

What is wasted sunlight?

Wasted sunlight very simply refers to sunlight to electricity that reaches solar panels but isn’t turned into electricity. It is ‘wasted’ usually because it is reflected off the panels and turned to heat, which further reduces a panel’s efficiency. This happens because the silicon material on solar panels can only turn a certain amount of sunlight into usable electricity.

The breakthrough comes amid a huge influx of cash for CPT; the company has raised more than £1.5 million in ‘pre-Series A’ funding (investment that usually happens before a much bigger round of funding called ‘Series A’) to ramp production of the photon-multiplier technology.

Dr Claudio Marinelli, CEO of CPT, said the funding shows that the private sector is confident in the technology’s potential to “transform solar efficiency at scale”.

Chris Gibbs, investment director at Cambridge Enterprise Ventures, one of CPT’s investors, said the technology showed the “kind of transformative innovation needed to accelerate the global transition to sustainable energy”.

The company is planning to use the funding to expand its research and development, with a goal of bringing its first product to market in the UK by 2028.

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Written By

Maximilian Schwerdtfeger Content manager

Max joined The Eco Experts as content manager in February 2024 and became deputy editor in 2025. He has written about sustainability issues across numerous industries, including maritime, supply chain, finance, mining, and retail. He has also written extensively for consumer titles like City AM, The Morning Star, and The Daily Express.

In 2020, he covered in detail the International Maritime Organisation’s (IMO) legislation on sulphur emissions and its effects on the global container shipping market as online editor of Port Technology International.

He also explored the initiatives major container ports and terminals have launched in order to ship vital goods across the world without polluting the environment.

Since then, he has reported heavily on the impact made by environmental, social, and governance (ESG) practices on the supply chain of minerals, with a particular focus on rare earth mining in Africa.

As part of this, in 2022 Max visited mines and ports in Angola to hone in on the challenges being faced by one of the world’s biggest producers of rare earth minerals.

His most recent sustainability-related work came much closer to home, as he investigated the eco-challenges faced by independent retailers in the UK, specifically looking at how they can cut emissions and continue to thrive.

Max lives in South London and is an avid reader of books on modern history and ghost stories. He has also recently learned to play the game Mahjong and takes every opportunity to do so. He is also yet to find a sport he doesn’t enjoy watching.

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