Enhanced performance of fiber-based perovskite solar cell achieved by multi-functional high polymer doping strategy

Toward the realization of efficient, durable, and sustainable fiber-based perovskite solar cells (fb-PSCs), a comprehensive optimization strategy focused on enhancing electron transport layer (ETL), perovskite (PVK) photovoltaic layer, and hole transport layer (HTL) is presented. A champion PCE of 10.66 % with 37.9 % relative enhancement over control has been achieved in the optimized fb-PSC. A significantly improved mechanical resilience and storage durability are also recorded. Decorating the SnO₂ ETL with methylammonium lead triiodide (MAPbI₃) strengthened the ETL/PVK interfacial integrity, and doping the MAPbI₃ layer with the multi-functional polymer of PJ71 remarkably enhanced the PVK layer's crystallization quality, and effectively passivated the grain boundary defects. A CO₂ pre-treatment of the spiro-OMeTAD HTL enhanced its hole conductivity. It is the synergetic combination of these methodologies that mutually contributed to the performance boost of the fb-PSC. The phenomenological model based on layer conductance shows that the PVK layer chiefly influences the device's anti-bending ability, followed by the ETL, and HTL the least impact. To further enhance the PCE of fb-PSCs, optimizing the interface and minimizing the stress-induced defects are essential. These measures, coupled with increasing carrier diffusion length and reducing surface recombination, are key to advancing the fb-PSC performance. An encapsulation with polyolefin elastomer substantially reduced the potential lead leakage of the device, and facilitated its eco-friendly application.