Investigating the Role of PM6:Y7 Layer Thickness on Optimizing Non-Fullerene Organic Solar Cells Performance Through Impedance Spectroscopy Analysis

Abstract

Recently, there has been significant improvement in the power conversion efficiency of non-fullerene organic solar cells, exceeding 19%. In this article, we have fabricated conventional sandwich structure of ITO/PEDOT:PSS/PM6:Y7/PDINO/Ag reaching efficiency up to 17.3% along with high generated current density of 30.60 mA/cm 2 for the optimized devices. The thickness of PM6:Y7 layer has been varied to investigate the impact on the overall device behavior. The obtained results showed that the PCE has been enhanced by 15% upon reducing its thickness from 150 nm to 100 nm. Accordingly, current-voltage measurements and impedance spectroscopy analysis through capacitance-voltage, Mott-Schottky analysis and capacitance frequency under different illumination intensities were conducted to evaluate the behaviour of the charge recombination due to thickness variation of the PM6:Y7 photoactive layer.

Keywords

• High efficiency nonfullerene based organic solar cells
• impedance spectroscopy
• charge carrier recombination mechanism