Promising alkoxy-wrapped porphyrins with novel push-pull moieties for dye-sensitized solar cells
Dye-sensitized solar cells (DSSCs) have been considered as very promising third generation solar cells. Porphyrins are promising candidates as highly efficient sensitizers for DSSCs because of their superior light-harvesting ability in the visible region and their mimicking of photosynthesis. This paper focuses on the structure modification of porphyrin dyes for efficient DSSCs, which was based on a rational design using density functional theory (DFT) before the experiment. We synthesized and fully characterized four porphyrin dyes, named ZLD13, ZLD14, ZLD15 and ZLD16. On one hand, we used 5-ethynylthiophene-2-carboxylic acid to replace 4-ethynylbenzoic acid as the electron-withdrawing anchoring group for the first time. Property studies indicate that the aggregation of porphyrin molecules can be sufficiently suppressed via this modification. On the other hand, 4,4′-di(2-thienyl) triphenylamine moiety, which has been proved to be a electron donor group for triarylamine dyes in our previous reports, was introduced to porphyrin dyes, and energy conversion efficiencies (η) were improved by 76% (ZLD15 vs. ZLD13). After the two modifications, the energy conversion efficiency (η) of ZLD16 is comparable with an N719-based reference cell under the same conditions. Enhancement of photovoltaic performances from ZLD13 to ZLD16 is partly due to the decreased dark current and charge recombination rate. the Partner Organisations 2014.