Enhanced Thermal Stability of Red‐Emitting Sr₂Si₅N₈:Eu²⁺ Phosphors from Triggered Applicable Trap Level via Rare Earth Ions Co‐Doping

Abstract

To solve the problem of thermal stability of the red‐emitting phosphor Sr2Si5N8:Eu2+ with great valuable luminescence performance, trivalent rare earth ions Ln3+ (Ln = Dy, Ho, Er, Tm, Nd, and Pr) are co‐doped into Sr2Si5N8: Eu2+ lattice to form thermally robust phosphors Sr2Si5N8:Eu2+,xLn3+(Lnx‐258, 0 ≤ x ≤ 0.05). The successful incorporation of rare earth ions in the crystal structure and the regulation of luminescent properties are proven by a variety of material characterization techniques and analysis. Although the co‐doping of the selected rare earth ions reduces the luminescence intensity of the phosphor, the Dy0.01‐258 sample still has a high external quantum efficiency (EQE) of 78.6%. More importantly, the co‐doping of Dy3+ with x = 0.01 significantly improves the luminescent thermal stability of phosphors at high temperature and the luminescence intensity of Dy0.01‐258 samples at 200 °C can be maintained at 94.7% of room temperature. The thermoluminescence spectrum shows that the defects brought about by co‐doping of Dy3+ with x = 0.01 introduce trap energy levels, which can compensate for the Eu2+ luminescence at high temperature. At the same time, the cathodoluminescence mapping and spectra show that the phosphor has a high saturation current under high‐energy electron bombardment, which indicates that this nitride phosphor also has the potential to be used in field emission display (FEDs). Based on its extraordinary EQE and thermal stability data, this nitride phosphor is the first‐rate among the red phosphors for pc‐wLEDs, and has excellent application prospects in FEDs.

Remarkable near-infrared emission enhancement of Cr3+-activated BaGe4O9: the role of lithium ions

“…The ionic radius differences between Li + and host cations (Table S1, ESI†) are all over 30%, surpassing the limit of an acceptable ionic radius difference for atomic substitution. 18 Li + substitution for Ba 2+ would lead to lattice contraction, due to the smaller ion radius of Li + compared to Ba 2+ . However, this hypothesis contradicts the results of the Rietveld refinements.…”

Progress of Ce3+/Eu2+ doped phosphors for violet chip based full-spectra lighting

“…17c. 207 Van Krevel first reported the orange-red M 2 Si 5 N 8 :Eu 2+ phosphor, with the component M variation, and the emission peaks can be tuned from 570 to 680 nm. Later, researchers studied thermal stability enhancement, e.g.…”

“…The thermoluminescence spectrum reveals that the defects brought about by Dy 3+ introduce trap energy levels, which can compensate for the Eu 2+ luminescence at high temperatures. 207…”

Effects of oxygen vacancies on the optical and electrical performances of silicon-based Er doped Ga2O3 films

“…As a kind of traditional effective luminescent material, rare earth ions have been widely used in the illumination and display fields owing to the high intensity and constant emission wavelength [18][19][20]. Among all the rare earth elements, erbium (Er) has attracted extra attention because the abundant energy levels within Er 3+ ions make the optical excitation easily accessible, and the ∼1.54 µm intra-4f transition of Er 3+ ions from 4 I 13/2 to 4 I 15/2 is situated in the minimum loss-window of quartz fiber, strategically important for the exploration of silicon-based light sources [21,22].…”