Investigations of Photoluminescence Properties of CaxMg2-xSi2O6:yEu2+ (x = 0.5-1.25, y = 0.015-0.035) Phosphors

Juan Lu; Chia-Ching Su; Cheng-Shong Hong; Guoxiang Peng; Cheng-Fu Yang

doi:10.3390/ma16052032

Investigations of Photoluminescence Properties of Ca_xMg_2-xSi₂O₆:yEu²⁺ (x = 0.5-1.25, y = 0.015-0.035) Phosphors

Materials (Basel). 2023 Mar 1;16(5):2032. doi: 10.3390/ma16052032.

Authors

Juan Lu¹, Chia-Ching Su², Cheng-Shong Hong², Guoxiang Peng³, Cheng-Fu Yang^{4

5}

Affiliations

¹ Department of Creative Design, Dongguan City University, Dongguan 523000, China.
² Department of Electronic Engineering, National Kaohsiung Normal University, Kaohsiung 811, Taiwan.
³ School of Ocean Information Engineering, Jimei University, Xiamen 361021, China.
⁴ Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung 811, Taiwan.
⁵ Department of Aeronautical Engineering, Chaoyang University of Technology, Taichung 413, Taiwan.

Abstract

Previously, there were almost no relevant studies on developing the optimal Ca_xMg_2-xSi₂O₆:yEu²⁺ phosphor composition for its finest optical properties. This study employs two steps to determine the optimal composition for Ca_xMg_2-xSi₂O₆:yEu²⁺ phosphors. First, CaMgSi₂O₆:yEu²⁺ (y = 0.015, 0.020, 0.025, 0.030, 0.035) was used as the primary composition of specimens synthesised in a reducing atmosphere of 95% N₂ + 5% H₂ to investigate the effect of Eu²⁺ ions on the photoluminescence properties of each variant. The emission intensities of the entire photoluminescence excitation (PLE) and photoluminescence (PL) emission spectra of the CaMgSi₂O₆:yEu²⁺ phosphors initially increased as the concentration of the Eu²⁺ ions increased, peaking at y = 0.025. The cause of the variations across the entire PLE and PL spectra of all five CaMgSi₂O₆:yEu²⁺ phosphors was investigated. Because the CaMgSi₂O₆:0.025Eu²⁺ phosphor had the highest PLE and PL emission intensities, in the next step, Ca_xMg_2-xSi₂O₆:0.025Eu²⁺ (x = 0.5, 0.75, 1.0, 1.25) was used as the primary composition to investigate the effect on the photoluminescence properties when the CaO content varied. We also show that the Ca content has an apparent effect on the photoluminescence properties of Ca_xMg_2-xSi₂O₆:0.025Eu²⁺ phosphors, and the optimal phosphor composition is Ca₀.₇₅Mg₁.₂₅Si₂O₆:0.025Eu²⁺ because it has the largest PLE and PL values. X-ray diffraction (XRD) analyses of Ca_xMg_2-xSi₂O₆:0.025Eu²⁺ phosphors were performed to identify the factors responsible for this outcome.

Keywords: Ca content; CaxMg2-xSi2O6:yEu2+; concentration quench effect; phosphors; photoluminescence properties.

Grants and funding

This research was supported by projects under Nos. MOST 110-2622-E-390-002, MOST 110-2221-E-390-020, and MOST 111-2221-E-390-018.