Enhanced efficiency of organic solar cells via Si-based non-conjugated small-molecule electrolyte as cathode interlayer

摘要

As an important approach to commercialize organic solar cells (OSC), research on solution-processable and low-cost interfacial materials with universal applicability has attracted much attention. In this work, three new non-conjugated small-molecules electrolytes (NCSMEs) with silicon as the core atom and sulfonate ion as the terminal group were synthesized, which were further applied as cathode interlayers (CILs) in non-fullerene and fullerene based OSCs. As the result, the power conversion efficiency (PCE) of 15.57% for non-fullerene PM6:Y6-based and 8.96% for fullerene PTB7:PC_(71)BM-based device was obtained, respectively. The improved performance was mostly attributed to the NCSMEs CILs which could mediate the energy barrier to form a better ohmic contact, enhance the charge transmission and collection efficiency, and decrease the charge recombination. It is noteworthy that the synthesized CILs could provide a new strategy for the potential applications of low-cost and highly efficient OSCs.