Novel Garnet-Structure Ca₂GdZr₂(AlO₄)₃:Ce³⁺ Phosphor and Its Structural Tuning of Optical Properties

Abstract

Aluminate garnet phosphors Ca2GdZr2(AlO4)3:Ce(3+) (CGZA:Ce(3+)) for solid-state white lighting sources are reported. The crystal structure and Mulliken bonding population of the CGZA:Ce(3+) have been analyzed. The larger 5d ((2)D) barycenter shift εc and smaller phenomenological parameter 10Dq of Ce(3+) in CGZA are related to the larger covalent character of Ce-O. The tuning spectral properties of the Ce(3+)-doped CGZA-based isostructural phosphors are presented. The splitting of cubic crystal field energy level (2)Eg in Ca2REZr2(AlO4)3:Ce(3+) (CREZA:Ce(3+)) (RE = Lu, Y, and Gd) increases as the radius of RE(3+) increases, and the splitting of (2)Eg may dominate the difference of spectroscopic red-shift D(A) in CREZA:Ce(3+). The splitting of the (2)Eg in CaGd2ZrSc(AlO4)3:Ce(3+) (CGZSA:Ce(3+)) phosphors increases seemly due to the decreasing of the covalent character of Ce-O. Thermal quenching properties of Ce(3+)-doped CGZA-based isostructural phosphors are also presented and analyzed. For CREZA:Ce(3+) phosphors, the increasing of the radius of RE(3+) results in an enhancement of thermal quenching. The quenching of CGZSA:Ce(3+) is obviously stronger mainly due to the smaller energy difference between the lowest 5d excited state and 4f ground state.

Synthesis, Structure, and Photoluminescence Properties of Ce3+-Doped Ca2YZr2Al3O12: A Novel Garnet Phosphor for White LEDs

“…Therefore, the 5d centroid shift is estimated to be 17 643 cm −1 , which is ∼3300 cm −1 larger compared to LuAG. 11 Meanwhile, the value of 10D q , 10 the splitting between the barycenter of T 2g and E g , is calculated to be 15 151 cm −1 , or ∼3600 cm −1 smaller than that of LuAG. This implies that the redshift of Ce 3+ emission in CYZA mainly arises from the nephelauxetic effect, while in LuAG it is mostly ascribed to the crystal field inducements.…”

The Energy Transfer and Thermal Stability of a Blue‐Green Color Tunable K2CaP2O7:Ce3+,Tb3+ Phosphor

“…RE ions can emit fascinating colors thanks to their special 4 f shell configuration. Different excitation energies and almost all the visible light spectrum from violet to red can be obtained by combining different RE ions and varying the ratio of dopants . In the green spectra region, Tb 3+ is a typical activator for its intrinsic emission peaking at around 545 nm originating from 5 D 4 to 7 F 5 transition.…”

“…Fortunately, Ce 3+ ions could be introduced as a sensitizer to intensify Tb 3+ emission . Meanwhile, the codoped phosphor generally exhibits f‐d absorption band of Ce 3+ ranging from UV to visible light relying on the nature of base materials, which significantly broadens the application of Tb 3+ ion. Ce 3+ and Tb 3+ codoped phosphors (e.g., MgZn 2 (PO 4 ) 2 :Ce 3+ ,Tb 3+ , Ca 3 Gd 7 (PO 4 )(SiO 4 ) 5 O 2 :Ce 3+ ,Tb 3+ , and Ca 2 Al 3 O 6 F:Ce 3+ ,Tb 3+ ) have been widely investigated, and the remarkable sensitization effect from Ce 3+ to Tb 3+ occurs in a variety of inorganic salts.…”

A blue-emitting Sc silicate phosphor for ultraviolet excited light-emitting diodes

“…Eu 2+ and Ce 3+ are the most commonly used activator for blue emitting phosphors. 7,8 The emission of Eu 2+ originating from the 30 4f 6 5d -4f 7 electronic transition is sensitive to the crystal field and covalency, exhibits broad emission bands from blue to red. 9,10 Eu 2+ -doped phosphors usually reveal strong absorption band in the region of 250-400 nm, which matches well with the emission of UV and n-UV LED chips.…”