Structural, optical, and dielectric properties of Co²⁺: Zn₂SiO₄ glass-ceramics for blue phosphor used in optoelectronic devices

Highlights

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Co²⁺ doped Zn₂SiO₄ (Co²⁺: Zn₂SiO₄) was fabricated using the recycled waste white rice husk ash (WRHA) based on empirical formula (Co₃O₄)_1.0[(ZnO)_55.0(WRHA)_45.0]_99.0 and produced by using melt-quenching technique.

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β- Zn₂SiO₄ started to form at 750 ℃ and single phase of α-Zn₂SiO₄ remain stable at 950 ℃.

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One triplet absorption band occurred at around 450 - 700 nm attributed to ⁴A₂ → ⁴T₁ (⁴P) optical transition of Co²⁺ ions that gives blue colour towards the Co²⁺: Zn₂SiO₄ sample.

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Emission spectroscopy of Co²⁺: Zn₂SiO₄ exhibit five different peaks corresponded to blue emission (~416 nm, ~441 nm, ~461 nm and ~484 nm) and green emission (~527 nm) under excitation at 325 nm.

Abstract

For the first time, the author reported the fabrication and characterizations of Co²⁺ doped Zn₂SiO₄ (Co²⁺: Zn₂SiO₄) using the recycled waste white rice husk ash (WRHA) based on empirical formula (Co₃O₄)_1.0[(ZnO)_55.0(WRHA)_45.0]_99.0 and produced by using melt-quenching technique. The precursor glass was heat treated at 700 ℃ until 950 ℃. The X-ray diffraction (XRD) result of Co²⁺: Zn₂SiO₄ showed that β- Zn₂SiO₄ started to form at 750 ℃ and single phase of α-Zn₂SiO₄ remain stable at 950 ℃. The Fourier transform infrared spectroscopy (FTIR) confirmed the formation of Co²⁺: Zn₂SiO₄ by showing eight significant vibrational bands. One triplet absorption band occurred at around 450 to 700 nm attributed to ⁴A₂ → ⁴T₁ (⁴P) optical transition of Co²⁺ ions that gives blue colour towards the Co²⁺: Zn₂SiO₄ sample. Emission spectroscopy of Co²⁺: Zn₂SiO₄ exhibit five different peaks corresponded to blue emission (~416 nm, ~441 nm, ~461 nm and ~481 nm) and green emission (~527 nm) under excitation at 325 nm. Such luminescence properties making Co²⁺: Zn₂SiO₄ as a potential phosphor material especially in providing blue emission supported by the excellent dielectric properties.