Dy and Eu activated Ca₃B₂O₆ phosphors for near ultraviolet‐based light‐emitting diodes

Abstract

The Dy‐ and Eu‐activated Ca3B2O6 phosphors were synthesized by a high‐temperature solid‐state reaction technique and their structural and luminescent properties were investigated. The phosphors are characterized by X‐ray diffraction, photoluminescence spectra, and Commission International de I'Eclairage (CIE) chromaticity coordinates. It is found that the charge compensator Na+ plays an important role in modifying the emission spectral profiles of Dy and Eu ions in the phosphors. The ratio of the emission located at the yellow wavelength portion to that located at the blue wavelength region of the Dy3+ ions can be apparently tuned by changing the Na+ content. The luminescence intensity of the phosphors can be enhanced with introducing Na+ ions as well. The emission colors of Dy/Eu codoped phosphors change from blue to white and successfully acquire the superior white light emission (x = 0.330, y = 0.329) by appropriately tuning the Na+/Dy3+ content and the excitation wavelength. The energy transfer process from Eu2+ to Dy3+ and Eu3+ occurs in the Dy/Eu codoped phosphors, providing a further approach to modify the emission spectral profile of the examined phosphors. The phosphors presented here have promising applications in the fields of light‐emitting diodes.

Huge enhancement of Sm2+ emission via Eu2+ energy transfer in a SrB4O7 pressure sensor

“…[31][32][33][34][35] Thanks to the large absorption in the UV region of Eu 2+ in many host materials, this ion may exhibit excellent sensitization effects to other lanthanide ions. [36][37][38][39][40] According to energy transfer (ET) mechanism, [41][42][43] such a process occurring from sensitizer (Eu 2+ ) to activator ions can effectively enhance emission of the luminophore. A host material based on the SrB 4 O 7 crystal structure is a good choice for effective combination of sensitizing properties of Eu 2+ ions with the targeted Sm 2+ activator ions, to enhance luminescence performance of the system.…”

Chemical bond parameters, bond energy and the local crystal sites of Eu3+ in Ca5(BO3)3F:1% Eu3+ phosphor

“…However, the excitation and emission spectra of Eu-doped Ca 3 B 2 O 6 are completely different with our luminescence properties of Eu-doped Ca 5 (BO 3 ) 3 F. The former shows an emission band peaking at 422 nm and excitation peaks at 362, 380 and 394 nm ( λ em = 616 nm). These prove that the different luminescence of Eu is due to Eu occupying the different sites in the Ca 5 (BO 3 ) 3 F. 26 …”

“…The emission spectrum at an excitation wavelength of 266 nm is shown in Fig. 3(d 26 When the Eu 3+ ion deviates from the center of the inversion, due to the opposite parity conguration in the 4f conguration, the parity selection in the crystal is relaxed and the 5 D 0 / 7 F 2 electric dipole transition will occur. If the Eu 3+ ion is located in the non-inversion center, its emission spectrum will be dominated by the 5 D 0 / 7 F 2 electric dipole transition, and the emission spectrum will be around 610 nm.…”

Ratiometric optical thermometry based on a Dy3+, Eu3+ co-doped GdAl3(BO3)4 phosphor

“…Besides, the energy transfer from Dy 3+ to Eu 3+ has been recognized in the study of luminescence color modulation with Dy 3+ and Eu 3+ co-doped phosphors. [21][22][23][24][25] It may also alleviate or intensify the thermal quenching of emissions from Eu 3+ or Dy 3+ , thus increasing the difference between the thermal sensitivities of their emissions.…”