Tuning Emission from Greenish to Blue via Chemical Composition Modulation in Solid Solutions (Sr_1–yCa_y)₂Sb₂O₇:Bi³⁺ under near-UV Light Excitation

Abstract

The Bi3+ ion, with an exposed 6s2 energy level sensitive for an external coordination environment, possesses complex and intriguing luminescent properties in various host lattices. Herein, we successfully prepared a new type of antimonate phosphor (Sr1–y Ca y )2Sb2O7:Bi3+ with controllable color emitting properties from greenish to blue stimulated by near-ultraviolet (UV) light. There are two emitting bands at 495 and 528 nm that go along with two crystallographic distinct Bi3+ sites in the Sr2Sb2O7 host. With increasing Ca constituents, enhancement of torsion resistance and the nephelauxetic effect would lead to the blue-shift of emitting bands. The internal quantum efficiency (IQE) of Sr2Sb2O7:0.03 Bi3+ and Ca2Sb2O7:0.03 Bi3+ was measured to be 51% and 62%, respectively. Finally, a white illuminating lamp was produced by using a 365 nm UV chip, blue phosphor Ca2Sb2O7:0.03 Bi3+, greenish phosphor Sr2Sb2O7:0.03 Bi3+, and red phosphor CaAlSiN3:Eu2+. This work can provide design insights into turning the emitting colors of Bi3+ doped phosphor by chemical composition modulation of the host lattice.

Closing the Deep-Blue Gap: Realizing Narrow-Band Deep-Blue Emission with Strong n-UV Excitation by Cationic Substitution for Full-Spectrum Warm W-LED Lighting

“…Usually, Bi + shows emission in the near-infrared region, Bi 2+ shows strong red–orange emission, and Bi 3+ emits strongly in the UV to green regions . Many Bi 3+ -doped phosphors excited with n-UV show similar blue luminescence properties. ,, Thus, the deep-blue emission is attributed to Bi 3+ . X-ray photoelectron spectroscopy (XPS) spectra of Sc 2 Si 2 O 7 :Bi 3+ and pure α-Bi 2 O 3 (99.99%) as a reference are shown in Figure S1.…”

“…22 Many Bi 3+doped phosphors excited with n-UV show similar blue luminescence properties. 20,23,24 Thus, the deep-blue emission is attributed to Bi 3+ . X-ray photoelectron spectroscopy (XPS) spectra of Sc 2 Si 2 O 7 :Bi 3+ 1a), which is attributed to the change in the crystal field strength and nephelauxetic effect around Bi 3+ with a reduction in the ionic radius.…”

Multiple Strategies to Approach High-Efficiency Luminescence Controllable in Blue/Cyan/Green-Emitting Bi3+-Activated Phosphors

“…It has been reported that n-UV LED chips + RGB phosphors (strategy three) is an effective method to solve the above problems, which can achieve whole-visible-spectrum white lighting. 12,13 However, this kind of pc-WLED still has the defect of cyan gap. If this problem can be solved, the lighting quality will undoubtedly be greatly improved.…”

“…Moreover, this combination of pc-WLED has a low Ra (<80) due to the lack of red and cyan light in the spectrum, which does not meet the requirements of high-quality white light illumination. − The second strategy also has the problem of intense blue light. It has been reported that n-UV LED chips + RGB phosphors (strategy three) is an effective method to solve the above problems, which can achieve whole-visible-spectrum white lighting. , However, this kind of pc-WLED still has the defect of cyan gap. If this problem can be solved, the lighting quality will undoubtedly be greatly improved. , Therefore, it is necessary to develop a high-efficiency cyan-emitting phosphor to close the cyan gap.…”

Effects of activated Sr 2+ ion content on strong blue‐emitting Ca 2 Sb 2 O 7 materials for high‐quality WLED devices

“…However, the investigation on its self‐host emission is not enough. Although Zhao et al prepared the tuning‐emission (Sr 1−y Ca y ) 2 Sb 2 O 7 :Bi 3+ phosphors and further considered that the luminescent behaviors originated from the featured emission of 1 S 0 → 3 P 1 (Bi 3+ ), 29 we identified that the self‐host emitting Ca 2 Sb 2 O 7 phosphors could reveal a strong pure blue emission with high color purity (90.78%) and QY (60.04%); and then it would exhibit color‐turning behaviors with the change of Sr 2+ ion content. Furthermore, some characterizations of crystal structure, elemental composition, morphology, thermal stability, luminescent dynamics, density functional theory (DFT), and luminescent efficiency for the resultant samples would be also investigated in detail in this work.…”