Different Morphology Of Zno Arrays Light Anode Preparation And Its Performance Study

Dye-sensitized solar cell (DSSC) has the advantages of low cost, simple process, stable performance and etc, so it is widely recognized as the most prospected one of solar cells, and it is the new method to promote the efficient utilization of solar energy. Since the research outcomes of professor M. Graztel had been published in the journal Nature in1991, world-wide fever to study DSSC has been set off. But so far the energy conversion efficiency of TiO2-based DSSC is still staying at about11%, and the stability need to be further improved. So other oxide semiconductors have been tried to be used as photoelectrode applied in DSSC in order to replace TiO2, among which, ZnO is the most promising one. In many studies of ZnO photoelectrode, ZnO arrays become the new research direction because of its characteristic of high speed electron transmission. In this article, ZnO arrays with different morphologies were prepared by using hydrothermal method which was low cost and easy to operate, and then assembled as DSSC and tested, aiming to explore the effect of ZnO arrays’morphology on DSSC performance. The concrete research content of this dissertation are as follow:(1) Sol-gel method cooperated with spin-coating process was used to prepare ZnO seed film, the effects of sol concentration and rotation speed on the quality of ZnO seed film were studied, and the best preparation condition was determined as:sol concentration0.75mol/L, rotation speed2500r/min, morphology of product was characterized by SEM, and the result showed that, the product was even and dense nanocrystalline ZnO film, which was made up of gathering fine particles, and the average particle size was50nm.(2) The effect of ZnO seed film on formation of ZnO arrays was studied at the same hydrothermal conditions, the results of SEM and XRD characterization indicated that coating ZnO seed on FTO substrate contributes to form well-ordered and smaller diameter ZnO nanorod arrays along the C axis.(3) ZnO nanorod arrays with different morphologies were prepared when changing the concentration of Zn2+in the precursor solution, it was known from SEM characterization results that the diameter of ZnO nanorod significantly increased when the concentration of Zn2+increased from0.02mol/L to0.20mol/L, but the length hardly changed, so the aspect ratio of ZnO nanorod arrays decreased. J-Vcharacteristic test showed that high aspect ratio and crystal structural integrity was beneficial to improve the DSSC performance of ZnO nanorod arrays.(4) When changing the hydrothermal reaction time under high concentration of Zn2+(0.20mol/L), ZnO arrays with special morphology was obtained, the SEM results showed that the obtained ZnO arrays had pits on the top when the concentration of Zn2+was0.20mol/L and the reaction time was12h. J-Vcharacteristic test indicated that this strange structure do advantage to the performance improvement of dye-sensitized ZnO nanorod array solar cell. The growth and dissolution process of ZnO crystal under high concentration of precursor solution was simulated by use of the growth unit model of anion coordination polyhedron, principles of chemical equilibrium and characteristics of ZnO crystal structure.