A new process for the remanufacturing of glass-encapsulated perovskite solar cells differs from conventional recycling by enhancing direct reuse of bulk materials with high environmental impact. The strategy goes beyond recycling by significantly reducing a module’s global warming potential (GWP).

An international team of researchers first examined module materials associated with high environmental impacts. The device studied includes a fluorine-doped tin oxide (FTO) front electrode, compact and mesoporous titanium dioxide, zirconium dioxide and a carbon-based back electrode, all encased with thermoplastic olefins (TPO), polyisobutylene (PIB)-based edge seal and a glass backsheet.

Only about 5% part of the cell stack’s GWP was associated with the materials of manufacture; most of the GWP contribution is linked to the energy and solvents used to deposit solar cell layers. The analysis pointed to the recovery and reuse of glass for the greatest GWP reduction.

Mechanical separation of the backsheet glass was performed by heating the cell up to 140° C, after which the encapsulants were placed in acetone and then peeled off. A bath of methylamine and ethanol liquefied and washed out the perovskite.

“The removal of perovskite and carbon allows reuse of the metal oxide layers deposited on the FTO in order to remanufacture encapsulated perovskite cells,” explained the researchers. “The layer morphology and thickness are preserved. Therefore, carbon deposition and perovskite solution infiltration, followed by the encapsulation with TPO and PIB can be performed again to complete the remanufacturing loop."

The remanufactured encapsulated devices described in ACS Sustainable Resource Management delivered a power conversion efficiency close to 90% of the original solar cells, along with a 33% GWP reduction.

Scientists from Fraunhofer Institute for Solar Energy Systems ISE (Germany), Solaronix SA (Switzerland), École Polytechnique Fédérale de Lausanne (Switzerland), University of Cambridge (U.K.) participated in this study.