Dye-sensitized Solar Cells Quasi-solid Electrolyte Codope Modification Research

Quasi-solid state Dye-sensitized Solar Cells(DSSCs) have advantages of simple packaging and preparation technology, diversified materials, long working life and high photoelectric conversion efficiency. With the scientific research value and practical value above, hence Quasi-solid state DSSCs have obtain the considerable technological achievements and long-term development since first present by now.Compared with DSSCs of liquid electrolyte, quasi-solid state DSSCs still have a certain practical gap on photoelectric conversion efficiency. It is mainly due to in the system of composite conducting polymer quasi-solid electrolyte based on PEO/ P(VDF-HFP), I3- and I2 can’t freely move as in liquid electrolyte, limited movement of I3-/I2 also decrease the ionic conductivity seriously and impede permeation with photo-anode, what is more, interface recombination also more serious than that in liquid electrolyte. Therefore modifying agent, crosslinking agent and plasticizer are added into quasi-solid electrolyte to reduce the effects of the above shortcomings. However, single additive often either brings little improvement on photoelectric conversion efficiency, or often act only on short circuit current(JSC) or open circuit voltage(VOC) with promotion effect but not for the other. So this article will study on using compound modifier to further enhance photoelectric conversion efficiency of quasi-solid DSSCs.In this paper, main work is as follows:1. Compared with liquid electrolyte, the ion conductivity of quasi solid polymer electrolyte is lower, ion sport ability is insufficient, free volume of the polymer chain segment is smaller, limiting the increase of JSC. In this paper, the mixed plasticizer of hydroxyethyl methylacrylate(HEMA) and ethylene glycol(EG) are studied on optimization content as modifier, to promote quasi solid dye sensitized solar cell(DSSC) photoelectric conversion efficiency. JSC and photoelectric conversion efficiency can be effectively improved from 13.11 m A/cm2 and 6.11% to15.23 m A/cm2 and 6.79%2. The single modifier often only makes for short circuit current or open circuit voltage,but not for or bad for the other, therefore hinders the further improvement on photoelectric conversion efficiency of thequasi-solid state DSSC. In this paper, the photoelectric performance of the quasi-solid state DSSC before and after modified with the mixture of the thiourea and 4- tert-butyl pyridine(TBP) will be discussed. The quasi-solid state DSSC modified with single thiourea and single TBP will also be studied to illustrate the advantages of mixture modifier on reducing the rate of interface recombination and improving the ionic conductivity. With the mixed-modifier, the JSC,VOC and photoelectric conversion efficiency(η) can be improved to 12.83 m A/cm2, 638.2m V, and 4.63%,compared with the original DSSCs of JSC of 12.46 m A/cm2, VOC of 601.6m V, and η of 4.15%...