Preparation And Photoelectrical Properties Of ZnO@Fe₂O₃ Nanoscale Core-shell Structure

Between the third generation of solar cells,dye-sensitized solar cell（DSSC）has been become a research hotspot because of its advantages of simple preparation technology,simple preparation conditions,lower cost,large area production,flexible bending and so on.In dye-sensitized solar cells,the photoanode is responsible for loading dyes,transmitting electrons and exporting electrons.It is the core part of the whole device.How to increase the specific surface area of the photoanode,suppress the dark reaction,expand the absorption of the photons and increase the load rate of the dye is the most important thing to improve the photoelectric conversion of the dye-sensitized solar cell.A new method for the preparation of spiral ZnO@Fe2O3 core-shell nanorods is proposed in this paper.The specific surface area of ZnO@Fe₂O₃ is larger which had been validated by emission electron microscopy,X ray diffraction and dye absorption.Through photoelectric performance test,it had been proposed that ZnO contacted with Fe₂O₃ would formed n/n heterojunction which was benefit for the photoelectron transport.The mechanism of n/n heterojunction formed had been explained reasonably by Mott-Schottky test.ZnO and ZnO@Fe₂O₃ had been encapsulated as dye-sensitized solar cells.Through a series of photoelectric tests,the effect of large injection in the battery had been proposed in this paper,and a reasonable explanation had been also given.It was concluded that the ZnO@Fe₂O₃core-shell structure could relieve the large injection effect of the battery which was encapsulated by ZnO.The main research work and achievements in this paper are as follows:（1）The similar spiral ZnO@Fe₂O₃ core-shell nanorod photoanode had been successfully prepared for the first time and the optimal process has been studied.It had been found that the specific surface area and the dye load rate had been increased by using XRD,SEM,dye absortion test.Meanwhile,the radiation recombination of ZnO had been weaken.It is noteworthy that this method could created a n/n heterojunction which was benefit for the optical electron transport after ZnO contact with Fe₂O₃.（2）Fe₂O₃ photoanode had been successfully prepared by magnetron sputtering.And ZnO,Fe₂O₃ and ZnO@Fe₂O₃ had been tested by Mott-Schottky.By the way,the flat band voltage had been fitted.The mechanism of n/n heterojunction formed after ZnO contact with Fe2O3had been explained using the fitted flat band voltage.（3）The DSSC using ZnO@Fe₂O₃ core-shell structure had been successfully prepared for the first time in this paper,and the ZnO@Fe₂O₃ after different times of compound cycle treatment was encapsulated into DSSC.It had been found that the optimal solution obtained by 6 cycle compound treatment was larger than ZnO.Meanwhile,the filling factor had been increased too.But the open circuit voltage had been decrease.（4）DSSC had been tested by dark current test,steady-state photocurrent test,electrochemical impedance spectroscopy and light quantum efficiency.It had been found that the DSSC filling factor based on ZnO was lower and the ZnO@Fe2O3 core-shell structure could improve the DSSC’s filling factor.The reason of it had been attribute to the large injection efficiency,not the dark reaction as usual.And a reasonable verification and explanation had been given.