New method converts waste plastic into high-performance electronics, like solar cells and transistors

Researchers from the University of Delaware (UD) and Argonne National Laboratory have discovered a way to transform a common eyesore – Styrofoam – into a valuable material for electronics. Their approach, detailed in a recent study published in JACS Au, utilizes a chemical reaction to convert waste polystyrene, the plastic found in Styrofoam, into a high-performance conducting polymer known as PEDOT:PSS.

This discovery holds promise for both the electronics industry and the environment. PEDOT:PSS is a versatile material with both electronic and ionic conductivity, making it ideal for various electronic devices. Traditionally, this polymer is synthesized using harsh chemicals. However, the UD and Argonne team successfully employed a milder sulfonation process.

The research, led by Dr. Laure Kayser, an assistant professor at UD's Department of Materials Science and Engineering, began with a simple question: could PEDOT:PSS be derived from plastic waste? Partnering with Dr. David Kaphan, a chemist from Argonne, the team explored the possibility of sulfonating polystyrene, the key component of Styrofoam.

Sulfonation involves replacing a hydrogen atom with sulfonic acid, a process commonly used in creating various products. However, finding the right balance is crucial. Harsh methods offer high conversion but generate harmful byproducts, while milder approaches are less efficient.

The researchers tested various conditions like solvents, ratios of the sulfonating agent, temperature, and reaction time. They designed a method that achieves high polymer sulfonation with minimal defects and impressive efficiency, all while utilizing a milder and more environmentally friendly approach.

"We can make electronic materials from trash, and they perform just as well as commercially available options," says Dr. Kayser. This reduces reliance on virgin materials and offers a valuable pathway for waste management.

The team successfully incorporated their waste-derived PEDOT:PSS into functional electronic devices, including organic transistors and solar cells. The performance of these devices was comparable to those using commercially produced PEDOT:PSS.

This breakthrough holds plenty of implications for the future of electronics and sustainability. Less than 23% of 62 billion kg (137 billion lbs.) of e-waste was documented as properly recycled in 2022 as per the Global E-waste Monitor Report 2024. This is exactly why research similar to this could be key in the future.