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 LaAlO 3 , LaAlO3:Dy 3+ and LaAlO 3 :Dy 3+ :Bi 3+ (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 4 F 9/2 → 6 H 15/2 , 4 F 9/2 → 6 H 13/2 and 4 F 9/2 → 6 H 11/2 levels, respectively, monitored at 265 nm. Also, spectra show the enhanced emission intensity when Bi 3+ 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 LaAlO 3 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 Dy 3+ doped and Bi 3+ 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.

High performance of broad excitation and narrow emission green phosphor NaAl11O17:Eu2+, Mn2+for backlight displays

“…The value of R c was calculated to be 12.69 Å (>5 Å), suggesting that the electric multipolar interaction plays a major part in the energy transfer process from Eu 2+ to Mn 2+ ions. Furthermore, to better understand the ET process, the following formula was calculated to judge the type of electric multipolar interaction: 40–42 I S0 / I S ∝ C n /3 where I S0 is the emission intensity of the Na 0.8 Al 11 O 17 :0.20Eu 2+ phosphor, I S is the emission intensity of the Na 0.8 Al 11− y O 17 :0.20Eu 2+ , y Mn 2+ phosphors at the contraction x , C represents the total concentration of Eu 2+ and Mn 2+ ions, and n denotes the type of electric multipolar interaction. The three kinds 6, 8 and 10 of n values corresponded to the dipole–dipole, dipole–quadruple, and quadruple–quadruple interactions, respectively.…”

“…The value of R c was calculated to be 12.69 Å (45 Å), suggesting that the electric multipolar interaction plays a major part in the energy transfer process from Eu 2+ to Mn 2+ ions. Furthermore, to better understand the ET process, the following formula was calculated to judge the type of electric multipolar interaction: [40][41][42]…”