New electron deficient acceptor-acceptor-acceptor type of monomer unit composed of weak electron accepting benzimidazole and relatively strong electron accepting benzothiadiazole derivatives namely 4,7-bis(6-bromo-1-(2-ethylhexyl)-1H-benzo[d]imidazol-2-yl)benzo[c][1,2,5]thiadiazole (BBB) was synthesized. The Stille polycondensation of the newly synthesized BBB monomer with electron donating 2,6-bis(trimethyltin)-4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b']dithiophene (BDT) afforded donor-acceptor-acceptor-acceptor type of polymer namely 2,6-(4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b']dithiophene)-alt-4,7-bis(1-(2-ethylhexyl)-1H-benzo[d]imidazol-2-yl)benzo[c][1,2,5]thiadiazole (PBDTBBB). The opto-electrical studies revealed that the absorption band of PBDTBBB appeared in the range of 300 nm-525 nm and its highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels were positioned at -5.18 eV and -2.84 eV, respectively. The power conversion efficiency (PCE) of the polymer solar cell (PSC) prepared from PBDTBBB:PC71BM (1:2 wt %) blend was 1.90%.
合成了一种新的电子缺乏型受体-受体-受体型单体单元,该单元由弱电子受体的
苯并咪唑和相对较强的电子受体苯并
硫二
噁唑衍
生物组成,即4,7-bis(6-broMO-1-(2-ethylhexyl)-1H-benzo[d]imidazol-2-yl)benzo[c][1,2,5]thiadiazole (BBB)。新合成的BBB单体与电子给体2,6-bis(trimethyltin)-4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b']dithiophene (BDT)进行Stille缩聚反应,得到一种供体-受体-受体-受体型聚合物,即2,6-(4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b']dithiophene)-alt-4,7-bis(1-(2-ethylhexyl)-1H-benzo[d]imidazol-2-yl)benzo[c][1,2,5]thiadiazole (
PBDTBBB)。光电研究表明,
PBDTBBB的吸收带出现在300 nm到525 nm的范围内,其最高占据分子轨道(HOMO)和最低未占据分子轨道(LUMO)的能级分别定位在-5.18 eV和-2.84 eV。由
PBDTBBB:PC71BM (1:2 质比)混合物制备的聚合物太阳能电池(PSC)的光电转换效率(PCE)为1.90%。