5,6-Bis(decyloxy)-2,1,3-benzooxadiazole-Based Polymers with Different Electron Donors for Bulk-Heterojunction Solar Cells
文摘
Four donor鈥揳cceptor (D鈥揂) alternating low bandgap photovoltaic copolymers, using 5,6-bisalkoxylbenzooxadiazole (BX) as an electron-deficient moiety and benzodithiophene or 2,7-carbazole or fluorene as an electron-rich unit, were synthesized and well characterized. The copolymers possess good solubilities, high thermal stabilities, broad absorption, as well as low bandgap ranging from 1.52 to 1.73 eV. Their electronic and photovoltaic properties can be easily tuned by incorporating different donor moieties into the polymer backbone. The HOMO levels of the copolymers were determined by the electron-donating segments, while their LUMO levels were mainly dominated by the BX unit. The preliminary photovoltaic device based on PBDT-DTBX:PC61BM gives a PCE value of 2.9%, which shows that BX probably is a promising electron-accepting building block in organic electronics.