Facile eco-friendly process for upcycled sustainable perovskite solar cells

Developing a green technology to eliminate the impact of the toxic element Pb and harmful solvent is a challenge for sustainable perovskite solar cells (PSCs). Herein, we report a facile eco-friendly process for upcycled sustainable PSC by screening the polar Pb solubilizers (N,N-dimethylformamide, DMF, dimethyl sulfoxide, DMSO and butylamine, BA) coupling with multi-function potassium iodide (KI) precipitator. We find that DMF with strong Pb-dissolution capacity and weak coupled C = O − Pb adhesion exhibits superb separation and recovery of Pb from obsolete PSC devices. Subsequent closed-loop management of the DMF completely eliminates its potential harm to the ecological environment. Interestingly, the KI precipitator added to the Pb-containing DMF solution not only induces the formation of high-quality PbI2 and thus high-crystallized defect-less perovskite matrix, but also relieves the residual tensile strain stemming from lattice expansion leading to orderly lattice orientation for perovskite crystallization. As a result, the re-fabricated PSC based on recovered components (PbI2, ITO and Ag) shows a PCE of 22.78 % higher than that (20.76 %) of PSC based on fresh components, also exceeding the reported record efficiency of PSCs based on one or more recovered components. Such a stable, environment-friendly, upcycled process of retired PSCs offers a sustainable pathway for eliminating the adverse factors such as toxic Pb leakage and harmful solvent effluence, and thus boost their competitiveness in future energy market.