Sustainable Solvent Management for Viable Perovskite Solar Cell Recycling Process

Sustainable recycling technologies of perovskite solar cells (PSCs) at the end of life is inevitable for commercialization, which can reduce the environmental impacts as well as re-fabrication cost. Thus, several efforts have been made to recycle toxic Pb compounds and expensive components in PSCs. However, most recycling strategies included dissolving layers such as perovskite and charge transfer layer by using organic solvents, which can cause harmful effects on environmental, health, and safety. Nevertheless, studies related to these toxic solvents used in recycling processes have not yet been considered. <br/>Here, we introduce a novel approach that recovers and reuses toxic solvents used in the recycling process. First, detailed evaluations were conducted to assess the effects of residual substances in PSC-dissolved solvents. Then, two-step dissolution process, which selectively dissolve spiro-OMeTAD and perovskite layer by layer, was introduced to minimize the factors affecting the efficiency reduction. PSCs were immersed in chlorobenzene and N,N′-dimethylformamide (DMF) solvents in sequence, and each solvent was recovered for reuse in the re-fabrication of PSCs. Especially, the recovered DMF was filtered by nano-absorbents for removing and managing toxic Pb ions. The recovered solvents were reused as precursor solvents to re-fabricate PSCs, and the dissolved spiro-OMeTAD also reused without any loss. Our results demonstrate the feasibility of a toxic solvent recycling process for PSC re-fabrication, which achieved a power conversion efficiency of 25.02%, comparable to that of the original PSCs (25.12%), as well as recycling of the dissolved hole conducting materials.