Multiple strategies for improving the stability of organic solar cells will be needed to make the technology more commercially viable.

Creating electricity from sunlight is a promising route to renewable and carbon-free energy, yet the processes to produce this electricity need to be sustainable. A team at KAUST has worked with international colleagues to make one group of emerging materials more efficient, durable and stable.

Silicon underpins the prevailing commercial solar-cell technology, however emerging alternatives made from organic materials, or organic–inorganic hybrids, hold potential if they can be produced more sustainably. These alternatives can be light, flexible and even transparent, making them useful in a much wider range of practical applications.

The Organic/Hybrid Materials for Energy Applications Laboratory (OMEGALAB) focusses on the development of these organic solar cells. Headed by Derya Baran, the lab aims to develop sustainable electronic materials and devices using low-energy processes and with minimal impact on the environment.

Organic solar cells neatly fit this ambition. They can be manufactured using so-called roll-to-roll printing, which may be less expensive and less energy-intensive than traditional solar cells. This, together with the fact that organic materials can be environmentally friendly and abundantly available reduces the technology’s impact.

The efficiency of organic solar cells has been improving and is now as high as 20 percent in the lab: so the scientists at OMEGALAB are also working towards another important goal of making the devices more durable.

One factor that limits the performance of an organic solar cell lies in its morphology, or the arrangement and structure of the different organic components. Stress in the device caused by temperature can alter the morphology and thereby degrade efficiency over time.

The team worked with colleagues at Jianghan University, China, and the University of the Basque Country, Spain, to show that the thermostability of organic photovoltaics can be significantly improved by introducing so-called thermoset materials.

“A cross-linked thermoset matrix is a type of polymer network formed by chemical bonds that create a three-dimensional structure,” explains Jianhua Han, a former postdoctoral fellow from KAUST, now at Julius-Maximilians-Universität Würzburg, in Germany.

Read more at KAUST Discovery.