Indacenodithieno[3,2b]thiophene-Based Wide Bandgap DA Copolymer for Nonfullerene Organic Solar Cells

Herein, a wide-bandgap (2.02 eV) donor-π-acceptor (D-π-A) polymer PIDTT-DTffBTA, composed of a rigid indacenodithieno­[3,2-b]­thiophene (IDTT) and fluorinated benzo­[d]­[1,2,3]­triazole (ffBTA) units as D and A units, respectively, is synthesized. In comparison with its analogue benzodithiophene-alt-benzotriazole copolymer J52 with classic benzodithiophene (BDT) as the D unit, PIDTT-DTffBTA demonstrates a lower-lying HOMO energy level and higher carrier mobilities when paired with a nonfullerene acceptor (NFA) Y6 based on a ladder-type dithienothiophen­[3.2-b]-pyrrolobenzothiadiazole central unit. Thus, PIDTT-DTffBTA:Y6 based organic solar cells (OSCs) exhibit an improved power conversion efficiency (PCE) of 11.05% than that of J52:Y6 (7.15%), which is also the highest value for IDTT-based photovoltaic polymers. This result proves that the IDTT unit is also a promising building block to construct not only NFAs but also p-type photovoltaic polymers

The effect of conjugated π-bridge and fluorination on the properties of asymmetric-building-block-containing polymers (ABC polymers) based on dithienopyran donor and benzothiadiazole acceptors

Inserting a hexylthiophene bridge between DTPa and BTs significantly reduced the intramolecular charge transfer and consequently affected the properties of the resulting ABC polymers.</p