Non-Fullerene-Based Inverted Organic Photovoltaic Device with Long-Term Stability

Abstract

In this work, we developed the PM6:Y6-based inverted structure organic photovoltaic (i-OPV) with improved power conversion efficiency (PCE) and long-term stability by resolving the origins of the performance deterioration. The deep defects between the metal oxide-based electron transport layer and bulk-heterojunction photoactive layer interface were responsible for suboptimal PCE and facilitated degradation of devices. While the density of deep traps is increased during the storage of i-OPV, the penetrative oxygen-containing defects additionally generated shallow traps below the band-edge of Y6, causing an additional loss in the open-circuit voltage. The suppression of interfacial defects by chemical modification effectively improved the PCE and long-term stability of i-OPV. The modified i-OPV (mi-OPV) achieved a PCE of 17.42%, which is the highest value among the reported PM6:Y6-based i-OPV devices. Moreover, long-term stability was significantly improved: ~90% and ~80% retention of its initial PCE after 1200 h of air storage and illumination, respectively.