| 초록 |
In this work, a new building block for low bandgap polymers, diketopyrrolopyrrole (DPP) flanked with pyridine (PyDPP), has been synthesized via a simple synthetic route and utilized as an electron-accepting unit for synthesizing a D-A type low band-gap copolymer (PBTPyDPP) by reacting PyDPP with 2,2’-bithiophene (BT) as an electron-donating unit. Since PyDPP acts as strong electron-withdrawing unit, PBTPyDPP had very low HOMO energy level of -5.8 eV which is much lower than TDPP-based copolymers, and thus the PSCs fabricated from PBTPyDPP exhibited a high VOC over 0.9 V, which is one of the highest reported value among DPP-based PSCs to the best of our knowledge, leading to a promising PCE of 4.9%. |
