Violet‐blue emission property of the cerium‐ion doped CaHfO₃: Doping and temperature dependence

Abstract

We investigated the emission property of perovskite CaHfO polycrystals with various concentrations of cerium ion (Ce ). With a wide range of UV photoexcitation, we observed a strong emission near 430 nm which should originate from 5d-4f transitions in the Ce ions. Combining these emission spectra with the photoluminescence excitation spectra, we estimated the Stokes shift to be 6700 cm , irrespective of the Ce ion doping concentration. We found that the violet-blue emissions in Ce ions showed non-trivial temperature dependence in their peak position and intensity. We found interesting low-temperature behavior of the violet-blue emission, which might be attributed to the thermal lattice effect in CaHfO . We also discussed our results with those of the similar materials, perovskite zirconates. Our systematic studies provide useful information on the host material CaHfO for a future study on the violet-blue emission of Ce ions.

Efficient Blue–Violet Phosphor with Small Stokes‐Shift for Full‐Spectrum Lighting

“…This means ΔS of the phosphors should be small enough to inhibit nonradiative energy loss during the emission process. [ 16 ] Indeed, most of the reported blue–violet phosphors can only be efficiently excited by the light shorter than 365 nm, such as Ca 2 MgSi 2 O 7 :Ce 3+ ( λ ex = 327 nm, λ em = 386 nm), [ 17 ] CaHfO 3 :Ce 3+ ( λ ex = 335 nm, λ em = 430 nm), [ 18 ] β ‐Ca 3 (PO 4 ) 2 :Ce 3+ ( λ ex = 269 nm, λ em = 400 nm) [ 19 ] and Ca 3 Al 4 ZnO 10 :Ti 4+ ( λ ex = 265 nm, λ em = 370 nm), [ 20 ] which severely limits their practical applications. In addition, phosphors with small ΔS are also important for other packaging technologies.…”

Energy Diagrams of Lanthanide Energy Levels in Perovskite‐Type Calcium‐Based Double Oxides Examined by X‐Ray Photoelectron Spectroscopy

“…CaHfO 3 has a wide energy gap and shows various luminescence by Ln 3+ doping. [ 48–51 ] Because of the large bandgap, violet‐blue luminescence from Ce 3+ ions can be observed in Ce 3+ ‐doped CaHfO 3 and energy transfer from Ce 3+ to Tb 3+ was reported for application to white LEDs. Although these luminescent perovskite‐type materials are anticipated for various applications, the information of the Ln 4 f levels referred to the HLs is scarcely available so far in these materials except for CaTiO 3 .…”

Synthesis and scintillation properties of Ce-doped CaZrO3single crystals

“…[16][17][18][19] CaHfO 3 has a high melting temperature above 2,400 °C, 20) thus the reports of the synthesis of CaHfO 3 are almost limited to ceramic or powder form. 21,22) After this pioneering research, by using a high temperature floating zone (FZ) method, we successfully obtained Ce-doped CaHfO 3 crystal and it exhibited a short decay time and comparable light yield with a commercial Bi 4 Ge 3 O 12 scintillator. 23) Analogous to CaHfO 3 , we focused on CaZrO 3 where Hf is changed to Zr.…”