Fabrication And Characterization Of One-dimensional Ferroelectric And Ferroelectric/Photoluminescence Nanofibers

Due to their excellent electro–mechano-optical properties, ferroelectric and piezoelectric materials have been widely used in actuators, sensors, energy harvesting, and micro-electromechanical systems. With the integration and miniaturization of microelectronics and optoelectronics devices, it is quite necessary to develop high-quality low-dimensional ferroelectric and ferroelectric composite functional materials. In this paper, one-dimensional ferroelectric and ferroelectric/photoluminescence nanofibers were prepared by a sol-gel based electrospinning method. Erbium was introduced into the ferroelectric host Ba Ti O3 with the formula Ba1-3x/2Erx Ti O3(BTO:x Er). The upconversion photoluminescence(UCPL) properties were systematically studied. On the other hand, lead-free(1-y)Bi0.5Na0.5Ti O3-y Ba Ti O3(BNT-BT, BNT-y BT), which exhibited excellent piezoelectric and electromechanical performance with the composition around the morphotropic phase boundary(MPB), were developed using the electrospinning method. The main research results are as follows:1. One-dimensional UCPL BTO:x Er nanofibers were prepared by a sol-gel based electrospinning method and the influence of the crystallization, rare earth ions concentration and temperature on the PL properties were investigated. With the annealing temperature increasing, the characteristic PL intensity significantly enhanced. In addition, the PL intensity increase first and then decrease with the increase of Er concentration. At x=0.02 a maximum PL intensity was obtained. Temperature dependence of the PL spectrum indicated that at ~130 oC, corresponding to the ferroelectric to cubic phase transition, an abnormal increase in the intensity was observed, which was considered to be ascribed to the crystal symmetry change.2. Lead-free BNT-y BT ultrafine fibers around the MPB(y=0,0.04,0.07,0.10) were synthesized by sol-gel based electrospinning method. X-ray diffraction(XRD), high-resolution transmission electron microscopy(HRTEM), and piezoresponse force microscopy(PFM) were utilized to characterize the phase, morphologies, and domain structures along with the nanoscale electromechanical response. Well-crystallized BNT-y BT fibers were obtained with good local piezoelectric response(d33,eff of ~84.0 pm/V,72.6 pm/V,109.0 pm/V,125.2 pm/V corresponding to y=0,0.04,0.07,0.10). It can be noticed that the BNT-0.10 BT exhibited the highest piezoelectric response which is different from the bulk system. This may be originated from the local contribution from the electrostatic response.