Reddish-orange emission from sol-gel derived Sm3+-doped Sr2La8(SiO4)6O2 phosphors

Singh, Vijay Pal and Lakshminarayana, G and Prabhu, Nimitha S and Kamath, Sudha D and Singh, N and Ashraf, Sara (2021) Reddish-orange emission from sol-gel derived Sm3+-doped Sr2La8(SiO4)6O2 phosphors. Optik, 227. ISSN 0030-4026

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In this study, Sr2La8-x(SiO4)6O2:xSm3+ (where x=(0.01 ≤ x ≤ 0.11)) phosphors were prepared successfully via the sol-gel route. Their structural properties were evaluated through fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) measurements. The XRD patterns confirmed the purity of the prepared compound that had an average crystallite size of ~38.8 nm. From the FTIR spectra, various stretching and bending vibrations of the SiO4 units were identified. The band observed at 540 cm− 1 was attributed to the normal vibration mode of La-O. The optical properties of the prepared phosphor were assessed through diffuse reflection spectroscopy and photoluminescence measurements. The diffuse reflectance spectrum exhibited seven peaks from the Sm3+ ions corresponding to f-f transitions from the ground state, 6 H5/2, to the excited states, 6 G7/2, 4 D7/2, 4 D3/2, 6 P7/2, 4 L15/2, 6 P3/2, and ( 4 I11/2, 4 I13/2). Out of all these transitions, the peak at 407 nm is the most prominent, this peak come from the 6 H5/2→6 P3/2 transition, which offers the maximum absorption. The phosphor’s excitation spectrum revealed a charge-transfer (CT) band that extended from 220 to 270 nm and was centered around 240 nm. The excitation spectra also exhibited several transitions of the Sm3+ ion, among these, the transition corresponding to 403 nm was chosen as the pumping wavelength owing to its promi�nence. The most intense emission peak was observed at 599 nm, this corresponds to the 4 G5/ 2→6 H7/2 transition. This emission’s CIE chromaticity coordinates placed it in the reddish-orange region, suggesting that the titled phosphor is suited for orange-red LEDs and the red component in WLEDs

Item Type: Article
Uncontrolled Keywords: Photoluminescence Sol-Gel Phosphor Reddish-orange emission
Subjects: Engineering > MIT Manipal > Physics
Depositing User: MIT Library
Date Deposited: 05 Oct 2021 09:18
Last Modified: 05 Oct 2021 09:18

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