【作者】 王威；

【导师】 胡永明； 顾豪爽；

【作者基本信息】 湖北大学 ， 微电子与固体电子学， 2013， 硕士

【摘要】 铌酸钾钠,(K1-xNax)Nb03,具有较高的机电耦合系数和较低的介电常数,是最具潜力的无铅压电材料之一。目前一维纳米材料的合成方法主要包括水热法、电化学沉积法、模板法、静电纺丝法等。本论文采用静电纺丝技术在衬底上大面积制备铌酸钾钠无铅压电纳米纤维,通过控制静电纺丝过程中的影响参数,实现了对铌酸钾钠纳米纤维的可控合成。制备了基于PDMS封装的元件,并研究其机电转换性能,通过控制叉指电极的间距,得到了相应的输出电压。1、采用溶胶-凝胶工艺与静电纺丝技术相结合,在单晶SiO2/Si衬底上制备钙钛矿结构(K0.5Nao.5)Nb03(KNN)无铅压电纳米纤维,研究静电纺丝实验过程中PVP的浓度、电场强度以及空气湿度等对获得的纳米纤维形貌的影响。在PVP浓度在0.06g/ml-0.08g/ml时形成的KNN纳米纤维均匀且形貌很好,但当PVP浓度过大或过小时,都不能获得形貌良好的纤维；通过控制电场强度的大小来控制纳米纤维的直径尺寸,控制空气湿度等条件来得到形貌良好的纳米纤维,当电压从6KV增加到14KV的过程中,纤维的直径分布呈现抛物线的形式,先增大然后减小,使KNN纳米纤维的直径在70nm-90nm范围,并研究发现当空气湿度控制在<40%时,得到的KNN纳米纤维形貌较好；通过比较不同的退火温度,研究了KNN纳米纤维的不同晶化行为,确定了在650℃退火处理后得到的KNN纳米纤维形貌最佳,获得了具有钙钛矿结构的纳米纤维。2、基于PDMS封装技术组装不同电极间距的KNN纳米纤维的机电转换元件,通过连续按压的方式对元件提供外力,用万用表和电脑连接采集数据,将机械能转换成的电能以电压的方式收集,研究电极间距对输出电压的影响发现随着叉指电极间距的增大,输出电压呈现递增的趋势,输出电压从最小的98mV,到最大225mV,通过多次的重复试验获得脉冲信号输出,相较于基于KNN纳米棒的机电转换特性有了明显的提高。更多还原

【Abstract】 Potassium sodium niobate (K1-xNax)NbO3nano-materials have great protential as a lead-free piezoelectric materials because of its high electromechanical coupling coefficient and low dielectric constant. Now KNN were synthesized by hydrothermal. Sol-gel and template methods. Although the nanorods obtained by those methods are single crystal structure, the length of the nanorods are limited. And can not gain much productions, In order to solve these problems, in this paper we use sol-gel method and electrospinning to prepare of KNN nanofibers. By change the paeameters of the electrospinning process to controllable synthesis of KNN. We also prepared based on PDMS packaging components, and study the mechanical and electrical transformation performance, by controlling the fork refers to the spacing of electrodes, get the corresponding output voltage.First, we use sol-gel method and electrospinning to prepare KNN nanofibers, Perovskite structure of the lead-free piezoelectric nanofibers (Ko.5Nao.5) NbO3(KNN) prepared on single crystal SiO2/Si substrate. By controlled the electrospinning experiment of PVP concentration to gain a nanofiber which the diameter of fibers were gradually increases, However, when the PVP concentration is too large or excessively small, the good morphology of the fibers can not be obtained. And when we controlled the size of the electric field intensity to control the size of the diameter of the nanofibers, and control air humidity conditions to obtain a good morphology of the nanofibers. When the PVP concentration at0.06g/ml-0.08g/ml, the KNN KNN nano-fibers are uniformly formed and have good morphology. When the voltage from6kV to14kV, the diameter of the fiber distribution presented in the form of a parabola, first increases and then decreases, and the KNN nanofiber diameter dimension in the range of70nm-90nm. And we also found that when the air humidity is controlled within the range at <40%, the resultant KNN nanofibers preferably morphology; Compared of different annealing temperatures, the KNN nanofibers have differentlly crystallization behavior, when identified by the annealing treatment at650℃, the nanofiber morphology were the best and the nanofiber have a perovskite structure. Secondly, KNN nano-fiber electromechanical transducer elements based on different electrode spacing of PDMS packaging technology are assembled. To components external force by a continuous press.we achieved to construction, assembly and test of a KNN nanofiber nanogenerator. The results show that nanogenerator can generate positive and negative output voltages under the transient external force (bending or pressing), and if we enlargement the separation distance, the output voltage enlargement, corresponding. We can generate output voltage, from the smallest98mV to the largest of225mV, Compared to the previous based the electromechanical conversion characteristics of the KNN nanorods has been significantly improved.更多还原