Investigation of structural, optical and dispersion parameters of [formula omitted] (A = Bi, Ce, and Y, with [formula omitted] = 0.0 and 0.1) compounds

V Tuyikeze,L.H Omari,F Fraija

doi:10.1016/j.ijleo.2021.166953

Abstract

Lanthanum titanate nanoparticles of La2−xAxTi2O7 (the undoped is denoted by LTO and the monodoped with Bi, Ce, and Y is denoted by LBTO, LCTO and LYTO, respectively) were prepared by sol-gel route. X-ray diffraction (XRD) reveals that these compounds crystallize as a monoclinic perovskite structure with a space group P21. Optical transmittance and reflectance made it possible to obtain more optical and optoelectronic of studied nanoparticles. The data collected reveal that the samples have a wide band gap (Eg) that varies between 3.50 and 3.88 eV. The dispersion parameters have been studied in terms of a single oscillator by the Wemple and Di-Domenico (WDD) model. The dispersion energy Ed, the excitation energy Eo have a crucial role in identifying the characteristics of optical materials and allow the calculations of the factors required for the design of spectral dispersion and optical communication devices.

Highlights

In recent years, the family of layered perovskite-type structure (LPS) has attracted more attention of researchers because of its multifunctional properties
Very few detailed studies on the optical properties of lanthanum titanate La2Ti2O7 have been reported in the literature, the aim of our work is to study these properties in order to help optoelectronics manufacturers interested in this material
The majority of the observed peaks are indexed according to the monoclinic structure with a space group P21, which is corresponding to PDF 96-100-9077 (ICDD,2006) card [24]

Summary

Introduction

The family of layered perovskite-type structure (LPS) has attracted more attention of researchers because of its multifunctional properties. This family has the general formula AnBnO3n+2, where n is the number of octahedral layers [1,2]. As one of the A2B2O7 structures, lanthanum titanate La2Ti2O7 has being the subject of several research due to its attractive properties such as ferroelectric and piezoelectric for hightemperature applications including automotive, aerospace and energy production [6,7]. Ferroelectrics with a layered perovskite-type structure (LPS) are good candidates for high-temperature applications due to their high Curie point (> 1200 °C), such as La2Ti2O7 (LTO, TC = 1461 °C) [8,9]. The layered structure of the La2Ti2O7 compound has a considerable interest due to its electrical, optical, and photocatalytic properties [10,11]

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