The Synthesis Of Dyes For Dye-Sensitized Solar Cells

Due to their high efficiencies and their potentially low production costs, dye-sensitized solar cells (DSSC) have attracted much attention during the last few years. Sensitized Solar Cell is unique in that it is very durable, lightweight, applicability, and can generate electricity in the low luminosity of indoor and outdoor. DSSC components can be effectively installed in the clothes, tents, electronic billboards, and can also be applied to the installations of solar PV systems in the buildings. Dye-sensitizer plays a key role in dye-sensitized solar cells. Dye sensitizers including metal organic dye sensitizers and non-metallic organic dye sensitizer, ruthenium complex dye which is recognized as the most effective and stable photo-sensitizer, but it is difficult to purify. Non-metallic dyes will be greatly developed because it is easy to design and synthesis molecular and get raw materials.This paper focuses on the synthesis of dye-sensitizer and includes the following three parts:I.4,4'-DimethyI-2,2'-bipyridine was synthesized with economic and high purity, from 4-methylpyridine using Pd/C instead of sodium chips and nickel compounds as catalyst.4,4'-dicarboxylic acid-2,2'bipyridine was directly obtained by using potassium dichromate as the oxidant and concentrated sulfuric acid, concentrated nitric acid as solvent avoid, and there is no byproduct 4-carboxylic acid-4'-methyl bipyridine which is not fully oxidized by potassium permanganate and chromium trioxide. We did research by two steps when preparing the final product, and found that in dark, high-temperature the maximum cis-Ru (dcbpyH2)2 (NCS)2was obtained instead of trans-Ru (dcbpyH2)2(NCS)2. It was possible to reduce the amount of the mixed N-/S-bound isomer to about 2% in higher boiling solvents under prolonged refluxing. At the same time, it can decrease the generation of cis-RudcbpyH2 (SCN)3 and cis-Ru(dcbpyH2)3 when more 20%RuCl3·3H2O was used. Finally, we also synthesize the cis-Ru (dcbpyH2)2(NCS)2 through one-pot method, it can save the solvent, simplify post-treatment, but also can achieve the same effect obtained through two steps.2. The fact that the N3 dye shed off easily when meeting water may be associated with the presence of hydrophilic group in its structure, such as carboxylic acid. After synthesizing the product N3, we also synthesized a novel dye (cis-(4,4'-dicarboxylic acid dimethyl-2,2'-bipyridine)-ruthenium cyanide disulfide) and two dyes intermediates (4,4'-dicyanoacetate-2,2'-bipyridine and 4,4'-diethyl cyanoacetate-2, 2'-bipyridine) in order to increase the capacity of dyes'adsorption ability to TiO2.3. At present, the Pure Organic dyes which have high photoelectric conversion efficiency contain D-π-A structure, and most researches are focused on Triphenylamine-π-A structure. We designed a new kind of Anthracene-π-A dye which uses Anthracene as electron donor. After calculation, we made the conclusion that the energy between the HOMO and the LUMO of the Anthracene-π-A structure is higher than that of Triphenylamine-π-A structure, but they are very close.So a kind of Pure Organic Sensitizer was obtained from 9-Anthraldehyde via reduction by KaBH4, Wittig reaction and Knoevenagel reaction, which includes the unit of Anthracene as electron donor.