Abstract
ABSTRACTA low band gap copolymer, P2TI (Eg = 1.6.eV), with bithiophene as donor and isoindigo as acceptor units is designed and synthesized by the direct arylation polycondensation (DAP) method. Absorbance of the polymer spans from 300 to 780 nm. It exhibits an absorption coefficient (ε) of 96 L/g cm in solution at its maxima. A HOMO level of −5.42 eV and LUMO level of −3.72 eV is measured by square wave voltammetry. ITO‐free solar cells fabricated using a P2TI:PCBM71 bulk heterojunction shows a moderate efficiency of 1.02% with a high open circuit voltage of 0.81 V. An intramolecular charge transfer state is found in the relaxation of P2TI in solution, which is generated with a time constant of 2 ps as measured by femtosecond‐transient absorption spectroscopy. Charge carriers were generated in <250 fs in P2TI:PCBM71 films. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 1475–1483
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
