Fabrication And Electro-mechanical Transformation Of K_0.5Na_0.5NbO₃Piezoelectric Nanofiber

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.