| 초록 |
Poly(3-hexylthiophene) (P3HT) is the most widely studied electron-donating material for use in bulk heterojunction (BHJ) solar cells. Although P3HT displays excellent charge transfer (CT) and separation properties, further improvements are needed. Much of the spectral energy is lost by the P3HT’s large energy difference between the lowest unoccupied molecular orbital (LUMO) levels of P3HT (3.2 eV) and the fullerene derivative ( 4.3 eV). We synthesized three classes of quinoxaline (Qx)-based donoracceptor (DA)-type copolymers via a Stille coupling reaction. The Qx unit was functionalized at the 2- and 3-positions with 4-(octyloxy) functionalized at the 2- and 3-positions with 4-(octyloxy)phenyl to provide good solubility and to reduce the steric hindrance. The PCEs of the polymer solar cells were 3.3% [P(T-Qx)], 1.9% [P(BDT-Qx)], and 2.3% [P(BDT-DTQx)], respectively. |
