Synthesis And Study On The Photovoltaic Properties Of Polymeric Metal Complexes Containing Fluorene And 8-Hydroxyquinoline

Dye-sensitized solar cells (DSSCs) become one of the most promising candidate photovoltaic cells due to the versatile, energy-saving, and environmentally friendly nature compared with inorganic solar cells. A dye is the core of such a cell. Sunlight is harvested by a dye, and then photo-excitation of the dye results in the injection of electrons into the conduction band of the oxide. The dye is one of the most important parts for DSSCs to obtain high efficiency and long life time. Until now, the performances of Ru-complexes have been greatest. However, the use of precious metal ruthenium brings about the high cost and the separation and purification of the dye is also very difficult. So, organic dyes are increasingly applied in DSSCs by virtue of their high molar extinction coefficient, easy preparation and purification, low cost, as well as their rich structures. Generally, donor-π-bridge-acceptor (D-π-A) structure is the common character of organic dyes. It is easy to extend the absorption spectra of dyes, effectively complete electron and charge separation, and hence improve power conversion efficiency of the DSSCs through enhancing electronic push-pull capacity of D-π-A system.Polymeric metal complexes formed by the coordination bonds between organic ligands and metal ions, possess advantages of both macromolecular and metal complexes. As a new kind of molecule materials, polymeric metal complexes have attracted increasing interest for their unique electrical, optical, magnetic properties in many fields.Under the above research background, we have designed and synthesized six D-π-A polymeric metal complexes. The works are listed as following:1. Polymeric metal complexes P1, P2, P3 and P4 have been designed and synthesized with substituted benzene, fluorene and carbazole unit as the electron-donor, 8-hydroxyquinoline metal chelates as the electron-acceptor and fluorene ethylene unit asπ-bridge, and characterized by FT-IR,'H-NMR and Elemental analysis.2. Polymeric metal complexes PF1 and PF2 have been synthesized with substituted benzene unit as the electron-donor, different 8-hydroxyquinoline metal chelates as the electron-acceptor and fluorene schiff unit asπ-bridge, and characterized by FT-IR,1HNMR and Elemental analysis.3. Electrochemical properties of six polymeric metal complexes (P1-P4, PF1 and PF2) have been studied. The results showed that the HOMO and LUMO levels of these polymers could meet the requirements of the sensitizers. The excited dye effectively injected electron into the conduction band of TiO2 and oxidized dye from the redox electrolyte required the electron to achieve regeneration of the dye.4. Thermal stabilities of polymeric metal complexes have been studied. The results showed that polymeric metal complexes possessed excellent thermal stabilities.5. The photovoltaic properties of dye-sensitized solar cells based on polymeric metal complexes have been investigated in this article. The DSSCs fabricated by P1, P2, P3 and P4 exhibited good device performance with power conversion efficiency of up to 0.34%,0.29%, 0.56% and 0.23% under simulated AM 1.5 G solar irradiation. Under the same conditions, the power conversion efficiency of the DSSCs fabricated by PF1 and PF2 were 0.34% and 0.29%, respectively.