Polymer solar cells for flexible power supply2019-12-12
At Karlstad University, there is research on polymer solar cells and how these can be made more stable and effective. Recently, a doctoral thesis was presented on how solar cell materials and functions are affected by contact with air and light.
”By now, almost everybody agrees that climate change is real,” says Vanja Blazinic, PhD in physics. ”We need to phase out fossil fuels and transit to renewable energy sources like sun, wind and water. I’ve carried out studies with a focus on sustainable and effective polymer solar cells.”
The goal is effective and sustainable solar cells
Solar cell research at Karlstad University has a focus on solar cells based on semi-conducting polymers, a special group of polymers that can absorb light and conduct current. Polymer-based solar cells are flexible, light and can be manufactured through common printing methods. In recent years, solar cell record efficiency has improved significantly in the world and the technology is approaching commercialisation. The final challenge is solar cell sustainability, or life span, that is, how long they can keep functioning and convert sunlight to electricity, before materials degrade. The overall aim of research is to improve solar cell stability and increase efficiency through increased understanding of molecular processes. The project was funded by the Swedish Energy Agency and the Research Council.
”Most materials exposed to strong sunlight will fade and age,” says Vanja Blazinic. ”The polymer solar cells have various layers, a photo-active layer converting sunlight to electricity between two layers transporting charges. In my study I exposed the layers to different influences to see where the degradation took place. A new research instrument was used which can reproduce the chemical composition of the photo-active layer with a high degree of dissolution on the nanometer scale. The instrument, which is a combination of atomic force microscopy and infrared spectroscopy, was procured by the research group thanks to a grant from the Knut and Alice Wallenberg Foundation. The aim is to produce more sustainable and efficient solar cells at a reasonable cost.”
Molecular electronics provides flexible solar cells
Solar cells made from polymers, long chains of carbon atoms, are cheaper to manufacture than the present silicon-based cells. Polymer solar cells have many good qualities. They can be made very thin and consist of soft materials so they can bend without breaking. This makes it possible to use polymer solar cells in applications where traditional solar cells cannot be used. Only imagination can limit the contexts in which they can be used, for example, charging the mobile without electricity grid, or providing electricity to rescue operations in natural disasters.
“As a child I was very interested in science and science fiction, and one thing has led to another,” says Vanja Blazinic. “I earned a Master’s degree at the university in Zagreb and my supervisor was active in a research network where Professor Ellen Moons at Karlstad University was a member. Because of this contact, I applied for a doctoral position here in Karlstad, and I’ve enjoyed my time in Karlstad. It’s the right size and I might stay here and start teaching again, which I have done previously and liked very much.”
Download the thesis: Probing the effects of photodegradation of acceptor materials in polymer solar cells: bulk, surface, and molecular level