The Performance Comparison Between Fullerene and Nonfullerene Interlayers in Inverted Organic Solar Cells. Issue 16 (7th July 2020) - Chen, Chunxin
Abstract : Inverted fullerene organic solar cells with cathode modifying layers (CML) of ZnO/electron acceptor/polyethylenimine ethoxylated (PEIE) are fabricated, where electron acceptor is either [6, 6]‐phenyl C71 ‐butyric acid methyl ester (PC71 BM) or a nonfullerene acceptor (IDIC). Compared to the devices based on conventional ZnO and ZnO/PEIE, the ones based on ZnO/PC71 BM/PEIE and ZnO/IDIC/PEIE show increased short‐circuit current densities ( J SC ), demonstrating both PC71 BM and IDIC interlayers enhance the exciton splitting in donor phase located at the bottom of photoactive layer. The nearly same values of J SC based on ZnO/PC71 BM/PEIE and ZnO/IDIC/PEIE imply the PC71 BM and IDIC interlayers have almost identical capabilities of splitting excitons in donor phase, governed by the quadrupolarities and stacking modes of electron acceptors. The PC71 BM and IDIC interlayers passivate the oxygen‐deficient defects of ZnO surface, leading to the increases in fill factor (FF) of device; the ZnO/IDIC/PEIE gives larger FF than the ZnO/PC71 BM/PEIE, indicating IDIC passivate ZnO more effectively than PC71 BM. The current research provides some helpful insights into developing high‐performance electron acceptors. Abstract : The fullerene and nonfullerene interlayers (PC71 BM and IDIC) are compared in inverted organic solar cells, in terms of splitting excitons in adjacent donor phase and passivating the defects of ZnO surface. The influences of the quadrupolarity and stacking mode of electron acceptors on the photocurrent generation of solar cell are discussed.