BIST Community centre ICIQ and researchers from two Universities in China show how molecular design can enhance copper-based solar devices, in a study published in Advanced Science. This work could mark an important step toward more efficient and stable solar devices.
A team led by Prof. Emilio Palomares at the Institute of Chemical Research of Catalonia (ICIQ), in collaboration with Hainan Normal University and Zhejiang University in China, has published a study in Advanced Science that reports a significant advance in dye‐sensitised solar cells (DSCs). This work could mark an important step toward more efficient, stable solar devices using abundant materials.
With global warming and rising energy demands, improving renewable energy technologies is urgent. Solar power is key among these, but many existing solar cell types are expensive, difficult to manufacture, or use rare materials.
In the current work, Heng Wu, first author, explains why they focussed on these approaches: “DSCs are eco-friendly and cost-effective photovoltaics that perform well in ambient light and can be made flexible and colourful. They’re ideal for portable, indoor, or decorative solar applications.”
One of their goals was to address limitations of typical DSCs, especially how to get higher voltage output and reduce loss of charges, while using more abundant substances (in their case, a copper‐based redox electrolyte).
What are Dye‐Sensitised Solar Cells (DSCs)
DSCs are a type of solar cell where photoactive dye molecules capture sunlight. These dyes transfer the energy to a semiconductor layer, generating an electric current. A liquid electrolyte then resets the dye so the process can continue.
Unlike traditional silicon panels, DSCs can be made semi-transparent or flexible, and their colour can be tuned. This makes them suitable for applications such as building windows or indoor devices. Their main challenge has been lower efficiency and charge losses compared to other solar technologies.
How this research advances the field
Prof. Palomares’ group designed and made two organic dyes, named H6 and H7, which differ in the length of certain chemical chains attached to them. These differences allow the researchers to study how the dye’s structure affects the speed of unwanted reactions such as charge recombination, how long the dye remains excited by light, and how effectively they absorb light over a range of wavelengths.
When using H7 together with a copper‐based electrolyte, the solar cell achieved a photovoltage (open-circuit voltage) of 1.22 volts, one of the highest reported for this kind of system. This high value comes from suppressing recombination of charges at the interfaces, lengthening the excited‐state lifetime of the dye (i.e. the time before the excited dye returns to its ground state without contributing to current), and excellent light absorption.
“Our study shows that by carefully designing the structure of the dyes, we can significantly improve the performance of dye-sensitised solar cells that use copper electrolytes. This includes reaching higher voltages and making better use of the captured light,” adds Prof. Palomares.
Reference publication
Co-Sensitized Solar Cell Achieves 13.7% Efficiency with Bis-Hexylthiophene Dyes
Wu, H.; Moncusí, L. M.; Li, J.; Martinez-Ferrero, E.; Wang, P.; Palomares, E.
Adv. Sci. 2025, e09116
DOI: 10.1002/advs.202509116
