https://phys.org/news/2018-07-solar-cells-roof-tiles-power.html

One way of improving solar power systems is by introducing new materials. The basic elements of a solar panel converting light into electricity are photovoltaic cells, or solar cells. They are mostly made of polysilicon—a highly pure polycrystalline form of silicon. But scientists are busy looking for alternative materials. Organic polymers with photovoltaic properties are one of the prime candidates to replace polysilicon.

A team of researchers from France (the University of Strasbourg, University of Lyon, Institut de Sciences des Matériaux de Mulhouse, Synchrotron SOLEIL), Russia (Moscow Institute of Physics and Technology, Moscow State University), and Kazakhstan (Nazarbayev University) has described a way of boosting the efficiency of organic solar cells by incorporating fluorine atoms in the polymer. This process, known as fluorination, was previously shown to enhance polymer photovoltaic properties, but the mechanism was poorly understood. The new study clarifies the effect of fluorination on cell efficiency.