New Low-Band Gap 2D-Conjugated Polymer with Alkylthiobithiophene-Substituted Benzodithiophene for Organic Photovoltaic Cells

[摘要] Two conjugated semiconducting copolymers consisting of 4,7-bis(4-(2-ethylhexyl)-2-thiophene)-2,1,3-benzothiadiazole (DTBT) and benzo[1,2-b:4,5-b']dithiophene with 5-(2-ethylhexyl)-2,2'-bithiophene (BDTBT) or 5-(2-ethylhexylthio)- 2,2'-bithiophene (BDTBT-S) were designed and synthesized as donor materials for organic photovoltaic cells (OPVs). Alkylthiosubstituted PBDTBT-S-DTBT showed a higher hole mobility and lower highest occupied molecular orbital (HOMO) energy level (by 0.08 eV) than the corresponding alkyl-substituted PBDTBT-DTBT. An OPV fabricated using PBDTBT-S-DTBT showed higher VOC and JSC values of 0.83 V and 7.56 mA/cm2, respectively, than those of a device fabricated using PBDTBT-DTBT (0.74 V) leading to a power conversion efficiency of 2.05% under AM 1.5G 100 mW/cm2 illumination.

[学科分类] 化学（综合）

[关键词] Organic photovoltaic cell;Organic thin-film transistor;Power conversion efficiency;Benzodithiophene