Solar power is the third most used renewable energy source and its popularity is growing.
Determining the efficacy of organic solar cell mixtures is a time-consuming and tired practice, relying on post-manufacturing analysis to find the most effective combination of materials.
Now, an international group of researchers – from North Carolina State University in the US and Hong Kong University of Science and Technology – have developed a new quantitative approach that can identify effective mixtures quickly and before the cell goes through production.
Development of a thin-film solar cell.Image: science photo/Shutterstock
By using the solubility limit of a system as a parameter, the group looked to find the processing temperature providing the optimum performance and largest processing window for the system, said Harald Ade, co-corresponding author and Professor of Physics at NC State.
‘Forces between molecules within a solar cell’s layers govern how much they will mix – if they are very interactive they will mix but if they are repulsive they won’t,’ he said. ‘Efficient solar cells are a delicate balance. If the domains mix too much or too little, the charges can’t separate or be harvested effectively.’
‘We know that attraction and repulsion depend on temperature, much like sugar dissolving in coffee – the saturation, or maximum mixing of the sugar with the coffee, improves as the temperature increases. We figured out the saturation level of the ‘sugar in the coffee’ as a function of temperature,’ he said.
