含均苯四甲酸二酰亚胺受体单元的共轭高分子的合成及其在有机太阳能电池上的应用

通过Stille反应合成了一系列含有均苯四甲酸二酰亚胺受体单元的共轭聚合物P1～P7.该系列聚合物在常见有机溶剂中溶解性良好,在370～600 nm范围内有较强吸收.通过循环伏安法测量其LUMO能级范围在-3.66～-3.90 eV之间,HOMO能级在-5.25～-6.17 eV之间,在同类分子中接近最低值.通过改变主链中噻吩单元的数量和给电子单元,可以调节分子的能隙,使其电化学能隙在2.45～1.55 eV范围内变化.将含均苯四甲酸二酰亚胺受体单元的P1～P7应用于有机太阳能电池中,作为给体材料与PC61BM共混制成本体异质结聚合物电池,器件开路电压普遍较高.其中基于均苯四甲酸二酰亚胺与二噻吩并噻咯的聚合物P7的器件,在AM 1.5 G,86 mW/cm2光照条件下,开路电压为0.72 V,短路电流为1.22 mA/cm2,能量转换效率为0.27%.

SYNTHESIS AND APPLICATION OF D-A CONJUGATED POLYMERS CONTAINING PYROMELLITIC DIIMIDE AS THE ACCEPTOR UNIT

Seven new conjugated D-A copolymers(P1～P7) containing a strong electron deficient pyromellitic diimide(PMDI) unit and a donor unit such as thiophene,bithiophene,benzo[1,2-b:3,4-b′]dithiophene,and dithieno[3,2-b:2′,3′-d]silole were synthesized by the Stille coupling reaction.P1～P7 possess good solubility in common organic solvents and exhibit strong absorption in the range of 370～600 nm.The electrochemical properties of P1～P7 were investigated by cyclic voltammetry(CV).The CV results indicate that the LUMO energy levels of P1～P7 lie in the range of-3.66～-3.90 eV,while the HOMO energy levels in the range of-5.25～-6.17 eV.The bandgaps of P1～P7 are tunable by incorporating of different donor units.The optical bandgaps for P1～P7 calculated from the absorption edge are 2.53～1.94 eV,and the electrochemical bandgaps are 2.45～1.55 eV.Polymers(P1～P7) containing the PMDI unit were applied to bulk heterojunction polymer solar cells(PSCs).High open circuit voltages(Voc) were obtained for these polymers due to their low HOMO levels.Under AM1.5 G illumination(86 mW/cm2),the PSC based on P7 with a pyromellitic diimide unit and a silole unit displayed an open-circuit voltage of 0.72 V,a short-circuit current of 1.22 mA/cm2 and a power conversion efficiency of 0.27%.