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

Abstract

Pyrochlore‐structured Y2Ti2O7 doped with Eu3+ activators via high‐temperature solid‐state reaction shows thermally stable orange‐red emission under near ultraviolet excitation. The concentration of Eu3+ activators was observed to influence both the intensity and color point of photoluminescence of Y2−xTi2O7:xEu3+ phosphors. The optimal doping concentration is around x = 0.45 determined by photoluminescence intensity; at this concentration, the luminescence branch ratio R/O=I(5D0−7F2)/I(5D0−7F1), named as the luminous intensity ratio of 5D0–7F2 (R) and 5D0–7F1 (O) transition is also at maximum, about 0.46. This orange–red emitting phosphor Y1.55Ti2O7:0.45Eu3+ shows excellent thermal stability in luminescence intensity, retaining 84% of room‐temperature luminescence at 250°C. Therefore, Y1.55Ti2O7:0.45Eu3+ phosphors may have great potential as an orange–red component for white light‐emitting diodes, especially for the high‐power devices.

Luminescent Properties of Eu3+-Activated Fluorogermanate Based Red Phosphor with High Thermal Stability

“…is within the error range associated with measurement and calculations. The activation energies are close to those of Y 2 Ti 2 O 7 :Eu 3+ (E a = 0.445 eV), 22 LaMgAl 11 O 19 :Eu 3+ (E a = 0.3 eV), 23 and Bi 2 SrTa 2 O 9 : Eu 3+ (E a = 0.25 eV). 15…”

“…Recently, the crystal structure of the first alkaline earth metal fluorogermanate (Sr 4 Ge 2 O 7 F 2 ) has been proposed by Akella et al 9 The optical properties of Eu 3+ have been investigated extensively due to their applications in the field of lighting and display. [10][11][12][13] Eu 3+ ion is usually used as a fluorescent probe to study the crystal structure of specific crystal. In general, the intense emission features are associated with the 5 D 0 → 7 F 1 transition (magnetic-dipole transition) and 5 D 0 → 7 F 2 transition (electric-dipole transition).…”

Color‐Tunable Up‐Conversion Emission and Infrared Photoluminescence and Dielectric Relaxation of Er3+/Yb3+ Co‐Doped Bi2Ti2O7 Pyrochlore Thin Films

“…In fact, cubic pyrochlore A 2 B 2 O 7 structures have been reported as host matrices for trivalent lanthanide activators . First principles calculation also shows that pyrochlore Bi 2 Ti 2 O 7 has a relatively low phonon energy.…”

Structure and photoluminescent properties of (200)-oriented Eu-doped CeO2 thin films fabricated on fused silica substrates by chemical solution deposition

“…Similar quenching phenomenon has been reported in various rareearth doped phosphors, and differs for different rare-earth ions, hosts, structures, grain sizes and annealing temperatures [27]. The quenching effect of Eu 3+ ions has been considered to be contributed by Eu-Eu energy transfer, phonon-assisted dipole and multi-pole energy transfer [28]. The Eu-Eu energy transfer is Eu-Eu distance dependent, which is effective only when the Eu-Eu distance is smaller than 5 Å [29].…”