Abstract
A new solution processable zinc phthalocyanine dye (ZnPc), as an interface modifier between poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C 61-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.
Original language | English |
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Pages (from-to) | 17209-17218 |
Number of pages | 10 |
Journal | Journal of Materials Chemistry |
Volume | 21 |
Issue number | 43 |
DOIs | |
State | Published - 21 Nov 2011 |