Enhanced efficiency in organic solar cells by incorporation of small molecule based on tosylate anion

A small molecule electrolyte (SME) based on tosylate anion (FN-NDI-OTs) was synthesized and applied as the cathode interlayer in organic solar cells (OSCs). This material generates a beneficial interface dipole at the cathode interface by the tosylate anion functionality, leading to the improvement of power conversion efficiency (PCE). The device based on the blend of PTB7-Th:PC71BM as the active layer exhibits improved PCE, increasing from 8.79% based on pristine ZnO to 9.53% using the ZnO/SME as the interlayer, which mainly resulted from the Jsc enhancement. These results indicate the potential of SME with tosylate anion as an interlayer in OSCs.