掺杂ZnO纳米材料的制备及其光电器件的应用研究

发布时间：2018-04-25 15:19

本文选题：ZnO + 掺杂ZnO　；参考：《北京交通大学》2017年硕士论文

【摘要】：ZnO是一种宽带隙的半导体材料,具有优良的光电性能和较高的化学稳定性,在发光器件和太阳能电池等领域有着广泛的应用,受到了研究人员越来越多的关注。近年来,ZnO纳米颗粒由于其特殊的电子结构和潜在的光电应用而受到人们广泛的关注。掺杂是一种有效的调控半导体纳米材料光电性质的重要手段之一,将适量的过渡金属离子掺杂到ZnO纳米颗粒中能够有效的改变其光学性能。本论文选取了 In3+和Mg2+作为掺杂离子,研究了其掺杂离子前后ZnO纳米颗粒的形貌、晶型、光学性质以及电学性质的变化。主要研究内容如下:1、采用溶胶凝胶方法以乙酸锌和四甲基氢氧化铵(TMAH)作为原料制备出尺寸小于10 nm的六方纤锌矿结构的ZnO纳米颗粒,其吸收峰位置位于355 nm,光致发光光谱由位于385 nm处较弱的蓝紫光和位于565 nm处较强的黄绿光组成,前者来源于ZnO的激子发射,而后者主要来源于ZnO内部的缺陷发射。在此基础之上,将乙酸铟作为铟源在ZnO纳米材料中引入In3+制备出ZnO:In3+纳米颗粒,随着In3+掺杂浓度的增加,颗粒的尺寸有所减小,而晶型仍然保持着六方纤锌矿结构。另外,随着掺杂浓度的增加,纳米颗粒的光学带隙从3.17eV变化到3.28eV,说明In3+的引入会增大材料的带隙。为了进一步研究掺杂离子对ZnO纳米颗粒的晶型、尺寸和形貌的影响,我们以乙酸镁作为镁离子的原料,制备出了 ZnO:Mg2+纳米颗粒,结果表明Mg2+掺杂浓度的增加也会造成纳米颗粒尺寸的减小,同时其光学带隙也会有所增加,这可能是由于Moss-Burtein效应造成的。但是,其X射线粉末衍射峰的峰位随着掺杂浓度的增加向较大2θ角方向移动,这可能是由于Mg2+比Zn2+半径小造成的。从两种掺杂不同金属离子的ZnO纳米颗粒的发光光谱我们发现,随着掺杂离子浓度的增加,蓝紫光的发光强度减弱,而黄绿光部分的发光峰强度有所增强,且发光峰位置有所蓝移,这可能是由于随着掺杂离子浓度的增加,光致发光逐渐由ZnO内部的缺陷发射转变为掺杂离子相关的发射。2:我们以无镉半导体量子点Cu-In-Zn-Se作为发光层,以ZnO:In3+纳米颗粒和聚合物poly-TPD分别作为电子和空穴传输层制备了器件结构为ITO/PEDOT:PSS/Poly-TPD/Cu-In-Zn-Se量子点/ZnO:In3+/Al的发光器件,结果表明随着ZnO:In3+纳米颗粒中In3+掺杂浓度的增加,发光器件的启亮电压由3V增加到5 V,In3+掺杂比例为5%时的发光器件的电流效率大于掺杂比例为1%和10%时的发光器件,其最大电流效率可达到0.36 cd/A。
[Abstract]:ZnO is a kind of wide band gap semiconductor material with excellent photoelectric performance and high chemical stability. It has been widely used in the field of luminescent devices and solar cells and has attracted more and more attention. In recent years, ZnO nanoparticles have attracted wide attention due to their special electronic structure and potential optoelectronic applications. Doping is one of the most important methods to control the photoelectric properties of semiconductor nanomaterials. Doping appropriate amount of transition metal ions into ZnO nanoparticles can effectively change their optical properties. In this paper, In3 and Mg2 were selected as doped ions to study the changes of morphology, crystal form, optical properties and electrical properties of ZnO nanoparticles before and after doping. The main research contents are as follows: 1. ZnO nanoparticles with hexagonal wurtzite structure smaller than 10 nm were prepared by sol-gel method using zinc acetate and tetramethylammonium hydroxide (TMAH) as raw materials. The absorption peak is located at 355 nm. The photoluminescence spectra are composed of weak blue violet at 385 nm and yellowish green at 565 nm. The former is derived from the exciton emission of ZnO, while the latter is mainly from the defect emission inside the ZnO. On this basis, ZnO:In3 nanoparticles were prepared by introducing indium acetate as indium source into ZnO nanomaterials. With the increase of In3 doping concentration, the size of ZnO:In3 nanoparticles decreased, while the crystal structure remained hexagonal wurtzite structure. In addition, with the increase of doping concentration, the optical band gap of nanoparticles changes from 3.17eV to 3.28 EV, which indicates that the introduction of In3 will increase the band gap of the material. In order to further study the effect of doped ions on the crystal shape, size and morphology of ZnO nanoparticles, ZnO:Mg2 nanoparticles were prepared by using magnesium acetate as the raw material of magnesium ions. The results show that the increase of Mg2 doping concentration will also decrease the size of nanoparticles and increase the optical band gap, which may be due to the Moss-Burtein effect. However, the peak position of the X-ray powder diffraction peak shifts to a larger 2 胃 angle with the increase of doping concentration, which may be due to the smaller radius of Mg2 than that of Zn2. From the luminescence spectra of two kinds of ZnO nanoparticles doped with different metal ions, we found that with the increase of doping ion concentration, the luminescence intensity of blue violet light decreases, while the luminescence peak intensity of yellowish-green part increases. The blue shift of the luminescence peak position may be due to the change of photoluminescence from the defect emission in ZnO to the dopant ion dependent emission. 2. We use cadmium free semiconductor quantum dot Cu-In-Zn-Se as the luminescent layer. ZnO:In3 nanoparticles and polymer poly-TPD were used as electron transport layer and hole transport layer respectively to fabricate ITO/PEDOT:PSS/Poly-TPD/Cu-In-Zn-Se quantum dots / ZnO: in / Al / Al devices. The results show that the doping concentration of In3 in ZnO:In3 nanoparticles increases with the increase of In3 doping concentration. The current efficiency of the luminescent device is higher than that of the luminescent device with doping ratio of 1% and 10%, and the maximum current efficiency can reach 0.36 cd/ Awhen the starting voltage of the luminescent device increases from 3 V to 5 V in 3%.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;TN15

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