Preparation And Application Of The Narrow Bandgap Spinel Powder In Dye-sensitized Solar Cells

Dye-sensitized solar cells(DSSC)is a new type solar cell that imitate photosynthesis.It is composed by Ti02 photoanode absorbed dye,electrolyte and electrode,The Ti02 photoanode play the role of absorbing the dye and transmitting the electrons.Therefore,the performance of TiO2 photoanode play a crucial role in the performance of the entire battery.However,the band gap of TiO2 is 3.2ev,it can absorb the energy of the ultraviolet region.So the utilization of sunlight is very low.So people began to seek ways to improve the performance of the TiO2 photoanode.Compositing the narrow band gap materials to Ti02 can improve the band gap of photoanode,and expand the reaponse range to sunlight.In this paper,the preparation conditions of CoAl2O4 and CoCr2O4 were studied.The spinel powders with whole crystal form and uniform particle size distribution were prepared.The absorbance of the spinel powders and particle morphology were characterized.Different content of spinel was added to Ti02 and the composite photoanode was prepared by screen printing method.X-ray diffraction instrument(XRD),transmission electron microscopy(TEM),UV-visible absorption spectroscopy(UV-Vis),a solar simulator(SS A 50)and Keithley SourceMeter(Keithley2400)?spectrophotometer(SM 25)were used to analysis.the prepared spinel powders and composite thin film cell.The results show that:(1)when the the CoAl2O4 powder sintering temperature of 700°C,the crystalline form is complete,and the particle size of CoAl2O4 powder is 24.8nm and the forbidden bandwidth for 1.69ev;the CoCr2O4 powder sintering temperature of 700 ?,the precursor complete the crystallization,the particle size of 33.5nm and band gap of 1.60ev.(2)Compared with pure Ti02 film,the absorbance of spinel/TiO2 composite film increases.CoAl2O4/TiO2 and CoCr2O4/TiO2 composite films exist absorption peak in the visble range of 550?600nm and 600?700nm,espectively.(3)Compared with the pure TiO2 thin film cell,the short-circuit and conversion efficiency of composite thin film cell increase.When the composite content for 1%,the short-circuit photocurrent and conversion efficiency of CoAl2O4/TiO2 thin film cell increased by 45.8%and 41.7%,those of CoCr2O4/TiO2 composite film cell is increased by 68%and 70%.(4)compared with pure Ti02 thin film battery,the IPCE of CoAl2O4/Ti02 and CoCr2O4/Ti02 composite thin film cells exist peaks in 550??650nm and 600?700nm.