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Synthesis of RE 6– x Ca 1.5 x Si 11 N 20 O ( RE = Yb, Lu; x ≈ 2.2) with Lu 6– x Ca 1.5 x Si 11 N 20 O:Ce 3+ Offering Interesting Spectral Properties for Yellow‐Emitting Phosphors in 1pcLEDs
Author(s) -
Gamperl Lisa,
Krach Georg,
Schmidt Peter J.,
Schnick Wolfgang
Publication year - 2019
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201901206
Subject(s) - phosphor , chemistry , crystal structure , crystallography , luminescence , full width at half maximum , x ray crystallography , rietveld refinement , doping , analytical chemistry (journal) , diffraction , materials science , optics , physics , optoelectronics , chromatography
The oxonitridosilicates RE 6– x Ca 1.5 x Si 11 N 20 O ( RE = Yb, Lu; x ≈ 2.2) were synthesized starting from RE F 3 , CaH 2 , and ”Si(NH) 2 ” in a radiofrequency furnace at 1600 or 1400 °C, respectively. The crystal structure was solved and refined from single‐crystal X‐ray diffraction data of dark red Yb 6– x Ca 1.5 x Si 11 N 20 O crystals in the trigonal space group P 31 c (no. 159) with a = 9.8281(10), c = 10.5968(13) Å and Z = 2. The structure represents a filled variant of the Er 6 Si 11 N 20 O structure type, in which the charge difference caused by substitution of trivalent Yb 3+ with bivalent Ca 2+ is balanced by occupation of an additional third cation site. Synthesis of Lu 6– x Ca 1.5 x Si 11 N 20 O:Ce 3+ resulted in a yellow powder with yellow luminescence. Powder X‐ray data were analyzed by Rietveld refinement based on the crystal data obtained from Yb 6– x Ca 1.5 x Si 11 N 20 O. The Ce 3+ doped compound exhibits a broad emission (fwhm ≈ 168 nm/≈ 5100 cm –1 ) with a maximum at λ em ≈ 565 nm. The emission extends more in the red spectral range compared to YAG:Ce 3+ , thus making it an interesting phosphor for warm‐white single phosphor converted light‐emitting diodes (1pcLED) with an improved color rendering index.