摘要
以Zn(NO3)2为原料,CO(NH2)2为沉淀剂,加入表面活性剂甲基丙烯酸甲酯,经微波加热制备获得颗粒尺度为亚微米级的ZnO。采用X射线衍射(XRD)、扫描电镜(SEM)研究了制备条件对样品结构、形貌的作用;PL方法讨论了其荧光发光光谱。发现采用微波加热法获得的ZnO呈球形,尺度在100nm左右,相比较,传统高温加热获得的样品呈c轴优先取向的短棒状。讨论认为,由于微波辅助方法能够使前驱物温度梯度变化小,表面Zn2+,O2+析出均匀,因此有助于获得球形的粉末粒子。
We reported the preparation of polycrystalline sub-micro ZnO powder using a two-step microwaveassisted synthesis method in which urea and zinc nitrate was used as precipitate to form a uniformity deposition and microwave radiation was employed to form spherical for polycrystalline ZnO particle. The as-prepared ZnO powder was characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and photoluminescence spectra （PL）.
The results showed that zinc nitrate was in decomposing urea solution at 90 ℃ accompany by methyl methacrylate for 2 h. After microwave-assisted radiation, the uniform ZnO spheres were obtained and the particle size was about 50 - 100 nm. For comparing, the non-microwave-assisted sample was also characterized which were c-axis oriented and in rod-like shape. The mechanism on preparation of spherical ZnO powder was discussed in this work. By treatment of microwave radiation, the precursor could be heated in uniform so that Zn^2＋ and O^2- on the surface resolved homogeneously and to promoting spherical ZnO particles easily.
X-ray powder diffraction patterns of ZnO sub-micro particles are illustrated. All peaks can be well indexed to the zincite phase of ZnO. No peaks from any other phase of ZnO and impurities were observed, it indicated the high purity of the obtained ZnO sub-micro particles. The PL spectrum showed that there were two main emission peaks in near ultraviolet and visible region respectively. The violet emission located at 420 nm with a FWHM of 60 nm was assigned to a donor-acceptor-type transition or radiative recombination of electrons in conductive band and holes from the valence band. The blue one at 470 nm with 30 nm FWHM was attributed to recombination of trapped electrons and holes from the valence band.
ZnO particle morphologies were very complex and diversiform in comparison with that of any other semiconductor. So far, monodispersed ZnO particles with well-defined morphological characteristics, such as, ellip-soidal, needle, prismatic, and rod-like shapes have been obtained, but spherical shape have not beendiscussed extensively. This paper pointed out a new application of microwave technology in the preparation of spherical ZnO.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2007年第3期425-428,共4页
Chinese Journal of Luminescence
基金
天津市科技创新能力与环境建设平台项目(06TXTJJC14601)
天津市自然科学基金(07JCYBJC06400)
天津市教委基金资助项目
关键词
均匀沉淀
微波辅助
球形ZnO
PL光谱
uniformity deposition
microwave-assisted
spherical ZnO
PL spectrum
