A Highly Crystalline Wide-Band-Gap Conjugated Polymer toward High-Performance As-Cast Nonfullerene Polymer Solar Cells

• A new wide-band-gap conjugated polymer PBODT was successfully synthesized that showed high crystallinity and was utilized as, the active material in nonfullerene bulk-heterojunction, polymer solar cells (PSCs). The photovoltaic devices based on the as-cast blend films of PBODT with ITIC and IDIC acceptors showed notable power conversion efficiencies (PCEs) of 7.06% and 9:09%, with high open-circuit voltages of 1.00 and 0.93 V that correspond to low energy losses of 0.59 and 0.69 eV, respectively. In the case of PBODT:ITIC, lower exciton quenching efficiency and monomolecular recombination are found for devices with small driving force. On the other hand, the relatively higher driving force and suppressed monomolecular recombination for PBODT:IDIC devices are identified to be the reason for their higher short-circuit current density (J(sc)) and higher PCEs. In addition, when processed with the nonchlorinated solvent 1,2,4-trimethylbenzene, a good, PCE of 8.19% was still, achieved for the IDIC-based device. Our work shows that such wide-band-gap polymers have great potential for the environmentally friendly fabrication of highly efficient PSCs.

Ämnesord

NATURVETENSKAP  -- Kemi -- Polymerkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Polymer Chemistry (hsv//eng)

Nyckelord

bulk-heterojunction polymer solar cells; charge-transfer state; crystallinity; energy loss; nonfullerene acceptor; wide-band-gap polymer

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