Enhancing organic photovoltaic performance with 3D-transport dual nonfullerene acceptors

Abstract

We used dual nonfullerene acceptors Y6:FINIC with 3D charge transport features and polymer donor PM6 to fabricate sequential-process heterojunction (SHJ) and bulk heterojunction (BHJ) organic solar cells (OSCs). FINIC has good compatibility with PM6 and Y6, facilitating efficient charge transport. It enhances photon absorption and electron transport, and reduces non-radiative recombination loss, contributing to increased V_OC, J_SC and FFs in both SHJ and BHJ OSCs. Moreover, the SHJ film has a more uniform FINIC vertical distribution and more PM6 at the bottom part of the films relative to the BHJ film, warranting better charge transport and collection. Finally, the SHJ OSCs based on Y6:FINIC yield power conversion efficiency (PCE) as high as 17.8%, higher than that of the BHJ counterpart (16.9%). Both SHJ and BHJ devices based on Y6:FINIC dual acceptors show higher PCEs than Y6-based binary OSCs (16.3% for the SHJ and 16.0% for the BHJ) and FINIC-based binary OSCs (13.4% for SHJ and 13.1% for BHJ).