Synthesis and characterization of small molecular electrolyte as an interlayer and its application in organic solar cells

A small molecule electrolyte (SME) based on the iodide ion (FN-NDI-I) was synthesized for organic solar cells as interlayers based on fullerene and non-fullerene systems. The utilization of ITO/ZnO/SME enhances the PCE of the fullerene-based device, with an increase observed from 8.63% (pristine ZnO) to 9.06%. In the non-fullerene case, the PCE of the device based on pristine ITO/ZnO reaches 14.9%. However, due to leakage current, the performance of the device using the ITO/ZnO/SME interlayer decreases to 11.5%. When ITO/SME is employed, the device attains a PCE of 14.5%, which closely approximates the performance of the non-fullerene device based on ITO/ZnO.