A novel donor–donor polymeric dyad of Poly(3-hexylthiophene-block-oligo(anthracene-9,10-diyl): Synthesis, solid-state packing, and electronic properties

A new polymeric dyad of oligo-anthracene-block-poly(3-hexylthiophene) (Oligo-ANT-b-P3HT) has been synthesized as a donor–donor dyad building block for organic photovoltaics. The polymer dyad and oligomer of anthracene-9,10-diyl (Oligo-ANT) are prepared by Grignard Metathesis. The higher order of crystallinity and molecular chains ordering at solid phase reveal the intrinsic optical and electrical properties of polymeric dyad resulting in relatively higher light harvesting ability compared to the oligo(anthracene-9,10-diyl). The UV-visible spectrum of (Oligo-ANT-b-P3HT) in solution shows broad absorption with two sets of absorption from both anthracene and thiophene core units, covering a wide range of the visible spectrum. The test devices of the blends of polymeric dyad with fullerene C₆₁ (PCBM) show improved photovoltaic performance with a power conversion efficiency of 3.26% upon subjecting to pre-fabrication thermal treatments. With optimized morphology of the interpenetrating network and the shorter fluorescence lifetime of the annealed dyad/PCBM blends, the effective charge transfer from the donor dyad to PCBM has evidenced. Thus, these studies will allow further synthetic advances to make potential high crystalline polymeric dyads with significantly improved light harvesting capability.