Unique light-induced degradation in yellow-emitting K₂SiF₆:Mn²⁺ phosphor

Journal Article · Tue Oct 07 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4897363· OSTI ID:22305748

Oyama, Takuya; Adachi, Sadao ^[1]

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1. Division of Electronics and Informatics, Faculty of Science and Technology, Gunma University, Kiryu-shi, Gunma 376-8515 (Japan)

Photo-induced luminescence intensity degradation in yellow-emitting K₂SiF₆:Mn²⁺ phosphor is studied using x-ray diffraction measurement, photoluminescence (PL) analysis, PL excitation (PLE) spectroscopy, PL decay analysis, and electron spin resonance (ESR) measurement. The yellow-emitting K₂SiF₆:Mn²⁺ phosphor exhibits remarkable degradation in the PL intensity under Xe lamp exposure. Coherent laser irradiation also induces degradation and its degree is in the order of He–Cd (λ = 325 nm) > Ar⁺ (488 nm) > He–Ne laser (632.8 nm). The degradation mechanism is proposed to be due to change in the valence state of manganese ions from Mn²⁺ to Mn³⁺ by the photooxidation (Mn²⁺ → Mn³⁺) or disproportionation reaction (2Mn²⁺ → Mn⁺ + Mn³⁺). The ESR measurement confirms the decreased Mn²⁺ spin density in the sample exposed with Xe lamp. The PLE spectrum suggests that the excitation of Mn³⁺ ions occurs through energy transfer upon absorption of exciting radiation by the Mn²⁺ ions. Thermal annealing of the degraded samples at ≥200 °C causes a blueshift in the PL emission band with an appearance of the Mn⁴⁺-related sharp red emission lines.

• OSTI ID: 22305748
• Journal Information: Journal of Applied Physics, Vol. 116, Issue 13; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
ANNEALING
ELECTRON SPIN RESONANCE
ENERGY TRANSFER
EXCITATION
FLUORINE COMPOUNDS
LASER RADIATION
MANGANESE ADDITIONS
MANGANESE IONS
OXIDATION
PHOSPHORS
PHOTOLUMINESCENCE
POTASSIUM COMPOUNDS
SILICON COMPOUNDS
SPECTRA
SPECTROSCOPY
SPIN
VISIBLE RADIATION
X-RAY DIFFRACTION