Study On The Preparation Technology And Optical And Electrical Properties Of Mg Or Bi Doped ZnO Nanorods

With the deepening of the degree of industrialization in various countries in the world,traditional fossil energy has been exhausted.Energy problems and pollution problems have gradually emerged,and it is urgent to find a new alternative environmentally friendly energy source.As an inexhaustible energy source,solar energy is rich in resources,but the current utilization efficiency of solar energy is too low.Semiconductor photoelectrode water splitting technology can use solar energy to produce clean and pollution-free hydrogen energy,which has become a research hotspot.The semiconductor ZnO is non-toxic and non-polluting,simple to prepare,and has a wide range of sources.It has certain application prospects in photoelectrochemistry,but its wide band gap makes it basically non-absorption of visible light,which greatly weakens its photoelectrochemical performance.In this paper,by changing the preparation method of the seed layer,doping with magnesium and bismuth elements to adjust the ZnO photoelectrode to improve its photoelectrochemical performance.The main research contents are as follows:ZnO seed layer was prepared on conductive glass（ITO）by electrochemical deposition method and pulsed laser deposition method,and a hexagonal wurtzite crystal ZnO nanorod array was prepared by electrochemical deposition on the basis of the seed layer.The nanorods grow longitudinally with the substrate as the bottom plate,and the surface and sides are smooth.The diameter of the circumscribed circle of the ZnO nanorods prepared by electrochemical deposition is about 550 nm,while the size of the ZnO nanorods obtained by the seed layer prepared by PLD is smaller,and the circumscribed circle of the nanorods is between 150 and500 nm.Fluorescence spectrum test and photoelectrochemical performance test show that the fluorescence intensity of S6 sample prepared by PLD method is lower than that of A1 sample prepared by electrochemical deposition,At the same time,the carrier recombination rate of P6sample is lower and the photoelectrochemical performance is better.The electrochemical deposition method was used to prepare Mg-ZnO nanorods with different doping concentrations.The test results show that the Mg-ZnO sample is still hexagonal wurtzite crystal form,and magnesium successfully replaced the Zn in the ZnO lattice.With the increase of Mg doping content,the diameter of the circumscribed circle of Mg-ZnO nanorods also increases,and the 10%Mg-ZnO samples can reach about 700 nm.Fluorescence spectroscopy and photoelectrochemical performance tests found that the 5%Mg-ZnO sample has the lowest fluorescence intensity,the lowest carrier recombination rate,and the best photoelectrochemical performance.The M-S curve shows that both ZnO and Mg-ZnO nanorods are N-type semiconductors,and the carrier concentration of the 5%Mg-ZnO sample is the largest.The electrochemical deposition method was used to prepare Bi-ZnO nanorods with different doping concentrations.The test results show that the prepared Bi-doped ZnO is still a typical hexagonal wurtzite crystal type,and the diameter of the Bi-ZnO nanorods is reduced,of which 5%Bi-ZnO sample is reduced to about 350 nm.XPS results showed that Bi was successfully doped into ZnO nanorods and existed in the form of Bi³⁺.The fluorescence spectrum test of Bi-ZnO sample shows that the impurity energy level introduced by Bi element doping can reduce the electron-hole recombination rate of the photoelectrode to a certain extent,and the electron-hole recombination rate of 5%Bi-ZnO sample lowest.The photoelectrochemical performance test and the M-S curve prove that Bi-ZnO is an N-type semiconductor,and the 5%Bi-ZnO sample has the highest carrier concentration and the best photoelectrochemical performance.