Lambda Energy QD retrofit solution for improved photovoltaic efficiency

Governments and companies across the globe have issued numerous pledges to reach net-zero CO2 emissions in the coming decades. However, the long term trends of energy consumption are clear, and the US Energy Information Administration predicts that global energy consumption will double by 2050\. Currently, global primary energy sources are more more than three quarters from fossil fuels. Meeting these pledges, and preventing catastrophic climate change, therefore requires the development of clean energy technologies.


Lambda Energy is a clean energy technology company that exploits the unique optical properties of semiconductor quantum dots to improve the efficiency of silicon solar panels (which account for approximately 95% of installed solar power). Silicon solar panels perform poorly at short wavelengths (i.e., UV, and to some extent also blue) because short-wavelength light is very strongly absorbed by silicon, and so the electron-hole pairs that are generated by the absorption of light are not created in the optimal region of the solar cells, rather at the front surface.

The idea of Lambda Energy's technology is that we absorb these shorter wavelengths using quantum dots before they reach the solar cell itself, and re-emit the light at longer wavelengths (i.e., red) where silicon solar cells exhibit optimal operation, by placing a layer of quantum dots at the surface of the solar panel. This approach is termed luminescent downshifting (LDS).

The idea is not new, however, and in fact the effect was first demonstrated in the 1970s. Despite promising results, however, it has not yet been commercialised. The reasons for this relate to the difficulties of creating stable dispersions of materials that have suitable optical properties, and can survive being exposed to strong sunlight for 25 years or so (the expected lifetime of a solar panel), and moreover doing so in a cost-effective manner.

Thanks to recent developments in nanomaterials processing, we believe it is now feasible to commercialise this technology. This project will develop a prototype LDS film that has the required optical properties to enhance the efficiency of silicon solar panels, can withstand the UV exposure that a solar panel is subjected to, and is suitable for application to existing solar panel arrays that are already installed. This will position us to carry out trials of the technology on existing solar panel arrays that are already installed, with the aim of increasing the power output of these installations by 10%.