All-Polymer Solar Cells Based on Fully Conjugated Donor-Acceptor Block Copolymers with Poly(naphthalene bisimide) Acceptor Blocks: Device Performance and Thin Film Morphology

摘要

All-polymer solar cells are fabricated by using poly(3-hexylthiophene) (P3HT) and fully conjugated donor-acceptor (D-A) block copolymer (P3HT-PNBI-P3HT) as donor and acceptor materials, respectively. Atomic force microscopy (AFM) and grazing incidence wide angle X-ray scattering (GIWAXS) analyses reveal that device performance strongly depends on the P3HT:P3HT-PNBI-P3HT thin film morphology. Indeed, theπ-πstacking nanomorphology rich in the edge-on orientation is formed in the P3HT:P3HT-PNBI-P3HT thin film by optimizing the fabrication conditions, for example, thermal annealing temperature and cast solvent. Consequently, the power conversion efficiency (PCE) of 1.60% is achieved with an open-circuit voltage (Voc) of 0.59 V, short-current (Jsc) of 4.43 mA/cm2, and fill factor (FF) of 0.61. These results suggest that P3HT-PNBI-P3HT has the huge potential for the usage as a nonfullerene acceptor material.