Photoluminescence and thermal stability of yellow-emitting Sr-α-SiAlON:Eu2+ phosphor

Eu2+‐doped strontium aluminum silicon nitrides having α‐SiAlON and polytypoid structures

“…Peak wavelengths (λ em ) and full widths at half maximum (FWHM) of the emission spectra of Sr 0.31 Al 0.62 Si 11.38 N 16 :Eu and Sr 2.97 Eu 0.03 Al 6 Si 24 N 40 excited with 400 nm wavelength light were 583 nm and 87 nm, and 584 nm and 91 nm, respectively. These emission peaks were close to those reported for Sr‐α‐SiAlON:Eu (Sr 0.355 Eu 0.02 Al 0.77 Si 11.23 N 15.98 O 0.02 , λ em =578 nm) and Ca‐α‐SiAlON:Eu (Ca 0.355 Eu 0.02 Al 0.77 Si 11.23 N 15.98 O 0.02 , λ em =581 nm) excited under 400 nm light irradiation . These emissions were explained by the allowed 4f 6 5d→4f 7 transition of Eu 2+ .…”

“…Two broad bands were observed at 297 nm and 386 nm in the excitation spectrum monitored with 590 nm emission from Sr 0.31 Al 0.62 Si 11.38 N 16 :Eu. Two similar bands with peaks at 288 nm and 399 nm were shown for the excitation spectra measured for Sr‐α‐SiAlON:Eu and Ca‐α‐SiAlON:Eu . Shioi et al.…”

“…Various visible light emissions have been realized by partial substitution of Eu 2+ for Ca 2+ and Sr 2+ in nitrides and oxynitrides. From the beginning of the nitride phosphor research, aluminum silicon oxynitrides, M ‐α‐SiAlON: M m/v Al m+n Si 12− m − n N 16− n O n ( M =Ca, Sr, Li, Ce, Eu, v: a valence number of M atom), have been representative phosphors . The framework of M ‐α‐SiAlON consists of corner‐sharing (Si/Al)(O/N) 4 tetrahedra and is isostructural with α‐Si 3 N 4 .…”

“…succeeded in preparing Sr‐α‐SiAlON:Eu 2+ at 2000°C and a nitrogen gas pressure of 1 MPa by reducing the m and n values to 0.7‐0.8 and 0.0‐0.05, respectively . They analyzed the crystal structure of Sr‐α‐SiAlON:Eu 2+ by Rietveld analysis for the powder synchrotron X‐ray diffraction (XRD) pattern and measured the peak of emission at 575 nm by 400 nm‐light excitation for a sample with a composition of Sr 0.355 Eu 0.02 Al 0.77 Si 11.25 N 15.98 O 0.02 . Seventy‐four percent of the emission intensity at room temperature was maintained at 300°C.…”

Thermally Stable Pyrochlore Y2Ti2O7: Eu3+ Orange–Red Emitting Phosphors

“…The thermal quenching temperature for Y 1.55 Ti 2 O 7 :0.45Eu 3+ phosphor is much higher than the surface temperature of LED chips, typically 200°C, generated during the LEDs action. This high thermal quenching temperature is even comparable to the nitride‐ or oxynitride‐based phosphors (e.g., Ca 2 Si 5 N 8 :Eu 2+ and Sr‐α‐SiAlON) . Note that the well‐documented Eu 3+ ‐activated molybdate red phosphors show much lower quenching temperature, for example, Li 3 Ba 2 Gd 3 (MoO 4 ) 8 :Eu 3+ only remain 60% of the RT emission intensity at 200°C .…”