E-tirucalli latex mediated green biogenic synthesized Dy³⁺ doped and Bi³⁺ co-doped nano perovskite lanthanum aluminum oxide: structure, morphology, luminescence and dielectric studies

Abstract

Perovskite structured LaAlO₃, LaAlO3:Dy³⁺ and LaAlO₃:Dy³⁺:Bi³⁺ (One mol%) nano materials were prepared by green biogenic method using of Euphorbia-tirucalli plant latex as a fuel. Rhombohedral structure with space group R 3 m having crystallite size of 18–28 nm was attained using X-ray diffraction spectra. The absorption peaks at 426 cm⁻¹, 677 cm⁻¹ and 825 cm⁻¹ for the spectral range between 840 cm⁻¹ to 400 cm⁻¹ would be endorsed to the characteristic metal oxide (M = La and/or Al) bonding. Irregular, flakes type surface and its constituents shown by scanning electron microscopy attached with energy dispersive spectra. Band gap energy by reflectance spectra shows 2.77–3.10 eV. Luminescence property exhibits the maximum wavebands at 450–490 nm, 540–580 nm and 650–675 nm resembles to the electron transition from ⁴F_9/2 → ⁶H_15/2, ⁴F_9/2 → ⁶H_13/2 and ⁴F_9/2 → ⁶H_11/2 levels, respectively, monitored at 265 nm. Also, spectra show the enhanced emission intensity when Bi³⁺ ion is co-doped. Color chromaticity and correlated color temperature of 7705 K confirm the practical usage as one of the component in cool white light emitting diodes. High dielectric for LaAlO₃ and conductivity contribution measured by Cole–Cole plot indicate that the appearance of semicircle at higher frequency zone signifies the grain contribution. Also, the resistance is increased for Dy³⁺ doped and Bi³⁺co-doped samples for the frequency range from 100 Hz to 8 MHz at room temperature. Hence, these materials are used in electronic storage, high frequency meter application and CMOS devices.

Graphic Abstract