Benzodifuran‐containing well‐defined π‐conjugated polymers for photovoltaic cells

Abstract

Two well‐defined alternating π‐conjugated polymers containing a soluble electroactive benzo[1,2‐b:4,5‐b′]difuran (BDF) chromophore, poly(BDF‐(9‐phenylcarbazole)) (PBDFC), and poly(BDF‐benzothiadiazole) (PBDFBTD) were synthesized via Sonogashira copolymerizations. Their optical, electrochemical, and field‐effect charge transport properties were characterized and compared with those of the corresponding homopolymer PBDF and random copolymers of the same overall composition. All these polymers cover broad optical absorption ranges from 250 to 750 nm with narrow optical band gaps of 1.78–2.35 eV. Both PBDF and PBDFBTD show ambipolar redox properties with HOMO levels of −5.38 and −5.09 eV, respectively. The field‐effect mobility of holes varies from 2.9 × 10−8 cm2 V−1 s−1 in PBDF to 1.0 × 10−5 cm2 V−1 s−1 in PBDFBTD. Bulk heterojunction solar cell devices were fabricated using the polymers as the electron donor and [6,6]‐phenyl‐C61‐butyric acid methyl ester as the electron acceptor, leading to power conversion efficiencies of 0.24–0.57% under air mass 1.5 illumination (100 mW cm−2). These results indicate that their band gaps, molecular electronic energy levels, charge mobilities, and molecular weights are readily tuned by copolymerizing the BDF core with different π‐conjugated units. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Tandem Synthesis of Photoactive Benzodifuran Moieties in the Formation of Microporous Organic Networks

“…Their electron‐rich nature has enabled them to be applied as redox‐active hole transfer materials in organic light‐emitting devices 5a. Moreover, very recently, anti ‐benzodifuran‐based organic materials have attracted significant attention as photo‐ and redox‐active materials in solar cells and organic field‐effect transistors 5b . anti ‐Benzodifurans can be prepared in the intramolecular cyclization reaction of 1,4‐hydroquinone with two alkyne groups at the 2,5‐positions.…”

“…Recently, benzodifuran‐containing organic polymers have shown promising photoelectrical performances in polymer solar cells 5b. In these photovoltaic devices, benzodifuran moieties acted as electron donors and photosensitizers.…”

Benzo[1,2-b:4,5-b′]difuran-based sensitizers for dye-sensitized solar cells

“…In previous studies we have developed efficient synthetic routes to fully functionalized BDF derivatives. [12][13][14][15][16] On this basis, we have been able to obtain two p-conjugated dyes (Fig. 1) that feature the BDF donor linked to one (Dye-1) and two (Dye-2) standard cyanoacrylic acid acceptors.…”

Evaluating chalcogen heteroatoms in conjugated polymers for organic electronics

“…Until recently, the general lack of synthetic routes to functional BDF has prevented its widespread use. [175][176][177] One of these syntheses produces BDF in a manner analogously to BDT (Scheme 1.1), only differing in the conditions of the alkylation step to give 4a. The incorporation of these BDF monomers into copolymers with benzothiadiazole gave good efficiencies of up to 5%.…”