Synthesis of copper(II)-imidazole complex modified sandwich-type polyoxometalates for enhancing the power conversion efficiency in dye-sensitized solar cells

摘要

A inorganic-organic hybrids based on copper(II)-imidazole complex modified sandwich-type tungstoantimonite H-6 [Cu(im)(4)] [Na2CU3(H2O)(3)CU(H2O)(2)(SbW9O33)(2)]center dot 36H(2)O(1) (im = imidazole) was hydrothermally synthesized and characterized structurally by single crystal X-ray diffraction analysis. Its central band is composed of four Cu 2+ and two Na + forming a rare plane hexagon, and the sandwich-type anions [Na2CU3(H2O)(3)CU(H2O)(2)(SbW9O33)(2)](8) are further joined into a one-dimensional chain by a [Cu(im)(4)](2+)cation. The Kubelka-Munk function F and electrochemical cyclic voltammetry (CV) indicate that the energy level of 1 match well with the conduction band of TiO2, and compound 1 can act as an electron acceptor to accelerate the transfer of electrons. The UV-vis absorption Spectra of 1 has a wide range, and the absorption range of TiO(2 )can be extended to the visible region to improve the light absorption of TiO2 after doping with TiO2. The incorporation of 1 into TiO2 as the photoelectrodes of Dye-sensitized Solar Cells (DSSCs) improves the J(se) (the short circuit current density) and PCE (the power conversion efficiency) of DSSC, the DSSC assembled with 5%1@TiO2/P25 photoelectrodes has the best performance and its J(se )and PCE is 17.54 mA cm(-2 )and 7.71% respectively, the improvement of the efficiency is 26.8% compared with pure P25 (6.08%). In addition, electrochemical impedance spectroscopy and open circuit voltage decay show that 1 can promote electronic transfer, suppress charge recombination, and extend electronic lifetime.