Synthesis And Characterization Of Carbazole Sensitized Dyes In Dye-Sensitized Solar Cells

Dye sensitizer plays a mainly important role in the terms of photoelectric conversion,and which is one of the core member in dye sensitized solar cells. Pure organic dye sensitizers has gradually become the first choice of the dye-sensitized solar cell sensitizer due to its own characteristics. Looking for a high conversion efficiency and simple synthetic method, low-cost organic dye sensitizer become the focus of people’s work around the world.By reading a lot of references, combined with the results of previous studies and the synthesis method, designed seven carbazoles dye sensitizer. We use N-ethyl carbazole as the electron donating group, and the cyanoacetate as the electron-withdrawing group, connecting the two parts together by converting different II bridge bonds. The structures of these dyes are confirmed by1HNMR, mass spectrometry and infrared absorption spectrum.The photophysical and electrochemical properties of these photosensitive dye was studied. These dyes were made into dye-sensitized solar cell devices and studied relationship between the structures of dyes and the cell performances. In addition, the theory of the density functional theory calculations of all dye molecules have been studied.Photophysical and electrochemical properties of the dye molecules is closely related to its structure. The absorption spectral range of the dye can be changed by varying the type of Ⅱ bridge. Experimental data show that the conjugated and coplanar of the dye molecules affect their photophysical properties and intramolecular electron transfer. Steric hindrance of Dye molecules are larger,the plane of the Dye molecules are the worse，which are resulting blue-shifted absorption spectrum of the the dye molecules and the photoelectric conversion efficiency of the battery device down.. Through the density functional theory calculations of dye molecules HOMO and LUMO levels while they are all meeting the dye excited electrons injected into the conduction band of TiO2and dye renewable energy level requirements.We have also tested electrochemical and photovoltaic properties of these dye sensitizers. Analyzed the results,we may get the relationship of these Dye sensitizers which are between the photoelectric conversion efficiency and the structural; Combined with the UV absorption spectrum data of the dye molecules, we can analyzes the relationship between the structure of the photosensitions and absorption spectrum. At the condition of the battery device fabrication unoptimized test case, in which the photoelectric conversion efficiency of the dye Ⅴ、 Ⅵ and Ⅶ are followed by2.03%,4.18%and2.74%.Replace their preparation conditions to be optimized, the photoelectric conversion efficiency may be increased to about5%-6%.