A professor at the University of Kansas is researching different ways to create painted-on solar panels to help edge away from the use of non-renewable resources.

Wai-Lun Chan, associate professor of physics, and his two Ph.D. students hope to find materials that decrease the cost of solar panels. This will, in turn, make them more accessible to the public.  

The conversation surrounding solar power versus fossil fuels has been a topic of interest for the last few years. According to the Solar Energy Industries Association, from 2006 to 2016, solar power had an annual growth rate of 50%, and within the last 10 years, there has been a 70% decrease in cost. 

Tika Ram Kafle, a Ph.D. student researching under Chan, found this opportunity through his passion of finding a better way to create solar energy. 

“I came from a background where I faced power cuts for more than 12 hours in a day,” Kafle, who's originally from Nepal, said. “So I used to think of alternative sources of energy, and solar energy was one of the alternative sources.” 

When Kafle was applying for his Ph.D., he specifically looked for research surrounding the improvement of solar power.

Chan is currently testing materials to understand how different molecules react with each other, searching for the best materials to combine in order to create these new painted solar panels.  

“So the goal of our research is to look into these new materials and how to make them suitable for different kinds of applications,” Chan said. 

Chan said when materials are received, the team determines which one of the molecules dissolved best into a solution. From there, they use that solution to paint on different surfaces.

The electrons and holes within the materials are essential to this process. At the beginning of the process, the electrons and holes are connected. However, in order to absorb solar energy, the electron needs to separate from the hole to create space. 

The trick, according to Ph.D. student Bhupal Kattel, is finding the correct materials to allow this process to take place. 

“When the solar cell is exposed to sunlight, it should ideally create free negative charges (electrons) and positive charges (vacancies/holes). But in these materials, these newly formed opposite charges tend to collapse with each other and can not come out of the devices,” Kattel said in an email. “So, we are trying to understand how to extract these carriers effectively before they collapse and neutralize."

To find the correct materials, Chan and his team work with chemists who send materials for them to test. From these samples, they can then determine which materials work best for the results they are looking for. 

“The material systems that we are interested in (organic semiconductors) are very interesting — they can be prepared using cheaper technology such as printing or coating and they are flexible like plastic,” Kattel said. “You can imagine how cool it would be if we could coat the windows of our houses or cars using those ultra-thin and transparent materials. If we do that, we can collect enormous energy so conveniently.”