Synthesis And Application Of Dyes With Novel П-bridges

Dye-sensitized solar cells (DSSCs) are new photovoltic devices with broad application prospects and have attracted significant attention due to their high efficiency and low cost. The dye is the key part in DSSCs, which is responsible for sunlight absorption, convertion of photons to excited electrons and injection the excited electrons to the conduct band of T1O2. Thus, the development of new dyes with satisfactory performance is becoming a new Research focus in the field of DSSCs. DSSCs based on ruthenium complexes with carboxyl bipridine dyes, such as N719, have achieved remarkable conversion efficiency up to11%However, the use of ruthenium complexes dyes, which need for expensive and rare metals with tedious purification processes are major problems for the cost and environmental pollution. Thus, developing novel and highly efficient metal-free organic dyes applied in DSSCs is current research focus.Fluorene and its derivatives are fit asπ-conjugated bridge to be applied in DSSC because of their good planar chemical structure and easily electron density adjusting by changing the substituent groups at9-positon. In this paper we synthesized two dyes (F-1and F-2) with9-fluorenone and9,9-diphenyl fluorene respectively as π-bridges, diphenyl amine as donor and cyano acetic acid as acceptor. Both of these structures were determined by1H NMR,13C NMR and MS. Their optical and electrical properties were also examined by ultraviolet spectra(UV), fluorescence emission spectra and cyclic voltammetry (CV) curves. These new two dyes (F-1and F-2) were also applied to DSSCs as sensitisers. The efficiency of the F-2sensitezed cell was up to5.08%.Dithieno[3,2-b;2’,3’-d]pyrrole(DTP) moiety also has a good planar chemical structure and high elcetron density. Thus, we designed and synthesized a new D-π-A organic dyes (DTP-1) with a N-butyldithieno[3,2-b;2’,3’-d]pyrrole moiety asπ-conjugated bridge, a simple triphenylamine moiety as the electron donor and cyanoacetic acid as the electron acceptor. Its chemical and physical properties were characterized. The DTP-1dye was applied to DSSC to produce1.53%efficiency.