Lead oxide

About: Lead oxide is a research topic. Over the lifetime, 2594 publications have been published within this topic receiving 24643 citations.

Lead Free Piezoelectric Materials

Abstract: Lead oxide based ferroelectrics, represented by lead zirconate titanate (Pb(Zr, Ti)O3) or PZT) are the most widely used materials for piezoelectric actuators, sensors and transducers due to their excellent piezoelectric properties. Considering lead toxicity, there is interest in developing piezoelectric materials that are biocompatible and environmentally friendlier. The low density of non-lead based materials can also be an advantage in transducers for underwater and medical imaging due to expected lower acoustical impedance. Another impetus for seeking alternative to lead based compositions is the need for piezoelectric materials for operation at high temperatures. Several classes of materials are now being reconsidered as potentially attractive alternatives to PZT for special applications. The potassium niobate family, KNbO3, exhibits low dielectric constants, large thickness coupling coefficient along certain non-polar directions, and low density, all of which have advantages for high frequency transducer applications. Several compositions belonging to bismuth titanate family, Bi4Ti3O12, such as SrTi4Bi4O15, are promising candidates for high temperature applications. Lead free materials alone (eg. (Na0.5Bi0.5)TiO3) or in solution with PT (BiScO3 – PbTiO3) are also potentially interesting as they combine high piezoelectric activity and, in some cases, relatively high T c . For these families of piezoelectric materials, the processing and piezoelectric response under different conditions of pressure, frequency, and temperature are presently much less understood than for the classical lead containing systems. In this presentation we review and discuss piezoelectric properties of selected lead free compositions (principally for members of the potassium niobate family and bismuth titanate layered compounds) in relation to structural and microstructural features as well as extrinsic contributions (domain walls displacement, conductivity) to their electromechanical properties. It is shown that it is possible to obtain remarkably stable piezoelectric response in some compositions, while others exhibit strong dependence of piezoelectric properties on driving field and frequency. Origins of these different behaviours are discussed.

Properties of piezoelectric ceramics in the solid-solution series lead titanate-lead zirconate-lead oxide: Tin oxide and lead titanate-lead hafnate

Abstract: Co mpositional proximity to a morphotropic t ransformation between two ferroelectric solid-solution phases seems to yie ld ceramic transducers having desirable properties over a wide range of te mperature. Examples of t his phenomenon were observed in the systems PbTi03-PbZr03, PbTi03-PbO:Sn02, PbTi03-PbZr03-PbO:SnO\" and PbTi03-PbHf03. The dielectric and piezoelectric properties of ceramics having compositions in these syste ms and in t he system PbZr03-PbO:Sn02 are described . The composition Pb (Ti .. 5Zr .5,) 0 3 ex hibits a high radial coupli ng coefficient, greater than 0.3, for temperatures as high as 275 0 C and has t he highest g31 constant, 1l .7 X 103 volt -meters per ne\\\\·toll . For the ser ies of compositions containing 30 percent PbO:SnO, in the ternary system PbTi03-PbZr03-PbO:Sn02 the tetragonal composition nearest the morphotropic boundary has the highes t d31 value, 74 X 1012 coulombs per newton . The rhombohedral composition nea rest. the morphotropic boundary sho\\\\'s the least change of frequency co nstant with temperature, a 2 perce nt variat ion over t he range of 25 0 to 225 0 C.

Structure and high-piezoelectricity in lead oxide solid solutions

Abstract: A review of the recent advances in the understanding of piezoelectricity in lead oxide solid solutions is presented, giving special attention to the structural aspects. It has now become clear that the very high electromechanical response in these materials is directly related to the existence of low symmetry monoclinic phases.

Halide-Rich Synthesized Cesium Lead Bromide Perovskite Nanocrystals for Light-Emitting Diodes with Improved Performance

Abstract: To improve the quality and durability of inorganic halide perovskite nanocrystals (NCs), ammonium halide and lead oxide (PbO) were separately employed for the synthesis of NCs with a tunable ratio of metal to halide. The halide-rich circumstance was therefore successfully set up and found to be beneficial for obtaining good quality NCs with high photoluminescence quantum yields and remarkable stability against purification compared to those qualities of previous regular methods with lead halide. The fabricated light-emitting diode (LED) devices with NCs made in a halide-rich circumstance demonstrated performance better than that of devices with NCs made in a halide-poor circumstance. A LED with CsPbBr3 NCs with a 1:4 Pb:Br ratio showed an obvious improved maximal luminance of 12090 cd m–2, a current efficiency of 3.1 cd A–1, and an external quantum efficiency of 1.194%, which were much higher than those of devices with NCs synthesized by the regular method.

Raman spectroscopy as a means for the identification of plattnerite (PbO2), of lead pigments and of their degradation products.

Abstract: The Raman spectra of plattnerite [lead(IV) oxide, PbO2] and of the lead pigments red lead (Pb3O4), lead monoxide [PbO, litharge (tetragonal) and massicot (orthorhombic)], lead white [basic lead carbonate, 2PbCO3·Pb(OH)2] and of their laser-induced degradation products were recorded using a range of different excitation lines, spectrometer systems and experimental conditions. The degradation of PbO2 is more extensive along the pathway PbO2 → Pb3O4 → PbO (litharge) → PbO (massicot) the shorter the wavelength of the excitation line and the higher its power. The Raman spectrum of PbO2, which is black and of the rutile structure, is particularly difficult to obtain but three bands, at 653, 515 and 424 cm−1, were identified as arising from the b2g, a1g and eg modes respectively, by analogy with the corresponding modes of isostructural SnO2 (776, 634 and 475 cm−1). A further oxide was identified, PbO1.55, the Raman spectrum of which does not correspond to that of any of the laser-induced degradation products of PbO2 at any of the wavelengths used. The Raman results are critical to the future use of Raman microscopy for the identification of lead pigments on artworks.