Efficiency enhancement of P3HT/PCBM bulk heterojunction solar cells by attaching zinc phthalocyanine to the chain-end of P3HT
作者:Jea Uk Lee、Young Do Kim、Jea Woong Jo、Jae Pil Kim、Won Ho Jo
DOI:10.1039/c1jm11563d
日期:——
A new solution processable zinc phthalocyanine dye (ZnPc), as an interface modifier between poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) in bulk heterojunction solar cells, was successively synthesized and linked to the chain-end of P3HT through the formation of a coordination complex. ZnPc dye molecules do not aggregate but preferentially locate at the interface between P3HT and PCBM, and thus contribute to the photocurrent generation by both direct photo-excitation and enhancement of charge transfer between P3HT and PCBM. To localize the zinc phthalocyanine dyes at the donor–acceptor interface more effectively, another new organic dye molecule, fullerene-functionalized zinc phthalocyanine (ZnPc-C60) was also synthesized and linked to the chain-end of the P3HT, where ZnPc-C60 contributes not only to the photocurrent generation by direct photo-excitation, but also lowers the interfacial tension, resulting in the reduction of the domain size and the suppression of the macrophase separation of the P3HT/PCBM blend for prolonged thermal annealing. This leads to higher device efficiency with 20% enhancement of the short circuit current and to enhancement of long-term thermal stability of device performance as compared to that of the reference P3HT/PCBM device.
一种新的可溶液加工的锌酞菁染料(ZnPc)被成功合成,并通过形成配位复合物与 P3HT 的链端相连,作为体异质结太阳能电池中聚(3-己基噻吩)(P3HT)与 [6,6]- 苯基-C61-丁酸甲酯(PCBM)之间的界面修饰剂。ZnPc 染料分子不会聚集,而是优先位于 P3HT 和 PCBM 之间的界面上,从而通过直接光激发和增强 P3HT 与 PCBM 之间的电荷转移来促进光电流的产生。为了更有效地将酞菁锌染料定位于供体-受体界面,还合成了另一种新的有机染料分子--富勒烯功能化酞菁锌(ZnPc-C60),并将其连接到 P3HT 的链端、其中,ZnPc-C60 不仅有助于通过直接光激发产生光电流,还能降低界面张力,从而减小 P3HT/PCBM 共混物的畴尺寸并抑制其在长时间热退火后的大相分离。因此,与参考 P3HT/PCBM 器件相比,器件效率更高,短路电流增加了 20%,器件性能的长期热稳定性也得到了提高。