Academic journal

A*Star and NTU scientists find a way to recycle old solar panels

SINGAPORE — Recycling old solar panels is a challenge, but scientists in Singapore have found a way to recycle the silicon inside and turn them into materials that can convert heat into electricity.

The team made up of researchers from the Agency for Science, Technology and Research (A*Star) and Nanyang Technological University (NTU) transformed old solar panels into thermoelectric materials.

These materials convert heat into electricity and work similarly to how hydroelectric plants use the movement of water to drive turbines to generate electricity.

The joint study was published in the scientific journal Advanced Materials in March.

Dr. Ady Suwardi, Deputy Director of the Soft Materials Research Department at A*Star’s Materials Research and Engineering Institute, said that by moving heat from side to side, thermoelectric materials generate electricity.

This can then be used for applications such as cooling, added Dr Ady, who co-led the study.

The team found that impurities and defects in the silicon used to make solar cells actually improve the performance of thermoelectric materials.

A solar panel is made up of several solar cells, also called photovoltaic cells.

Separating the materials used to make solar panels and recycling each one is a complex and expensive process, said Associate Professor Nripan Mathews.

Professor Mathews, Head of the Renewable Energy and Low Carbon (Solar) Generation Cluster at the Energy Research Institute @NTU ([email protected]), added that current recycling methods only recover glass and metal support structures for solar panels. .

Solar cells contain a complex mixture of materials such as aluminum, copper, silver, lead, plastic and silicon.

Silicon, extremely pure, constitutes 90% of solar cells. However, this normally ends up in landfills.

This is because the silicon must be chemically treated and remelted to be recycled into pure silicon, Professor Mathews said.

He added that it is difficult, energy-intensive and expensive to recover silicon to create new functional solar cells.

“Although silicon has very little weight in the whole solar panel, it is the most valuable part of it, which is why it is important for us to try to recycle it,” said Professor Mathews.