Preparation And Controllable Growth Of ZnO Nanorod Arrays By Sol-gel Method

One-dimensional ZnO nanorod arrays have good application prospects in the fields of optics,electricity,photocatalysis and photoelectric conversion due to their unique structure.There are many methods for preparing onedimensional ZnO nanorod arrays.Among them,the sol-gel method has simple equipment,low cost,easy doping of elements,precise control of composition,and easy deposition of large-area substrates compared with other preparation methods.It can be used in industrial production,but the growth mechanism of ZnO nanorod arrays prepared by sol-gel method is still unclear,and the controllability of aspect ratio,density and orientation is poor.This study aims to establish a suitable growth model to achieve the purpose of controlled growth of aspect ratio,density and orientation of ZnO nanorod arrays,which is of great significance for promoting the preparation of one-dimensional ZnO nanorod arrays by sol-gel method.In this study,ZnO nanorod arrays were prepared by sol-gel method using scanning electron microscopy(SEM),X-ray diffractometry(XRD),X-ray photoelectron spectroscopy(XPS),transmission electron microscopy(TEM)and fluorescence spectrophotometry(PL).The microstructure,crystal structure and optical properties of ZnO nanorod arrays were systematically studied by the experimental experimental technique.The main research work is as follows:The ZnO nanorod arrays were prepared on the substrate glass by sol-gel method.The effects of preparation parameters on the structure of ZnO nanorod arrays were studied,and the optimal process parameters for the preparation of ZnO nanorod arrays were determined.The results show that the ZnO nanorod array has the best aspect ratio,density and orientation when the doping concentration of Al is 4.0 at.%,the pretreatment temperature is 513 K,the final processing temperature is 823 K,and the final treatment time is 30 min.The in-situ heating was carried out in the preparation process by sol-gel method to study the influence of thermal field on the structure of ZnO nanorod arrays.In-situ heating can make the doping element distribution more uniform to affect the nucleation and growth of ZnO nanorod arrays,and improve the density and aspect ratio of ZnO nanorod arrays.One-dimensional ZnO nanorod arrays were prepared on different substrates with buffer layer by sol-gel method.The effects of substrate surface on the structure of ZnO nanorod arrays were investigated.In addition,the effect of the film interface on the structure of the ZnO nanorod arrays was investigated by controlling the thickness of the single layer film.Based on the comprehensive experimental results and analysis,a suitable growth model was established.The growth of ZnO nanorod arrays firstly forms larger nanoparticles or nanohills through the orientation-joining mechanism.The smaller nanoparticles are oriented in the[0001]direction by the orientation-attachment mechanism,and the Al2O3 precipitated the grain boundaries of the film inhibits the in-plane growth and promots the out-ofplane growth.ZnO nanorod arrays are gradually formed according to competitive growth mechanisms.According to the established growth model,the doping elements were changed,and the effects of co-doped elements on the structure and properties of ZnO nanorod arrays were investigated by co-doping with La and Al.The results show that La and Al are co-doped,and the aspect ratio of ZnO nanorod arrays can be significantly improved with the increase of La doping concentration.When only La is doped,the long diameter of the ZnO nanorod array is relatively uniform,but the orientation is poor.Its optical properties,with the increase of La doping elements,the ultraviolet luminescence peaks appear blue shift,and the intensity of the ultraviolet luminescence peaks increases.