Bismuth activated blue phosphor with high absorption efficiency for white LEDs

Qi-wu, Dong; Xiong, Puxian; Yang, Jiaojie; Fu, Yubin; Chen, Weiwei; Yang, Fengli; Ma, Zhijun; Peng, Mingying

doi:10.1016/j.jallcom.2021.160960

Cited by 37 publications

(20 citation statements)

References 66 publications

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“…In order to understand the dynamic luminescence characteristics of BGG:0.5%Bi glass, the fluorescence decay curves of the three PL peaks (430 nm: λ ex = 315 nm; 780 nm: λ ex = 330 nm; 1120 nm: λ ex = 350 nm) are plotted in Figure 3D–F. The decay curve can be fitted into a double‐exponential equation 35 :

\begin{equation}I\left( t \right) = {A}_1\exp \left( { - \frac{t}{{{\tau }_1}}} \right) + {A}_2\exp \left( { - \frac{t}{{{\tau }_2}}} \right)\end{equation}

…”

Section: Resultsmentioning

confidence: 99%

Heat treatment to regulate bismuth valence toward enhanced radiation resistance in barium gallo‐germanate glass

et al. 2022

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Due to the excellent infrared transparency, low phonon energy, and high rare‐earth solubility, germanate laser glass has attracted much attention in mid‐infrared fiber lasers for potential coherent laser radar systems, optical detection, remote sensing, and laser surgery. However, radiation‐induce darkening often occurs in fiber lasers that operate in radiation environment. Here, we report a useful strategy to improve the radiation resistance by adding multivalence Bi ions and discuss its radiation resistance mechanism. In order to study the effect of valence states on the radiation resistance of barium gallo‐germanate glass, we adjust the valence states of Bi ions by heat treatment, the potential mechanism of which is discussed in detail based on the absorption, photoluminescence (PL), and Raman spectra. The absorption, electron paramagnetic resonance, and photoluminescence spectra have proved the interconversion of Bi ions between low and high valence, which inhibits the formation of Ge‐related electron center (GEC) and non‐bridging oxygen hole center defects in the irradiation process. In addition, the Bi3+ content increased by heat treatment is beneficial to serve as electron‐trapping centers in γ‐ray irradiation, thus further reducing the formation of GEC. This study provides a simple method to achieve Bi valence regulation, so as to improve the radiation resistance.

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\begin{equation}I\left( t \right) = {A}_1\exp \left( { - \frac{t}{{{\tau }_1}}} \right) + {A}_2\exp \left( { - \frac{t}{{{\tau }_2}}} \right)\end{equation}

…”

Section: Resultsmentioning

confidence: 99%

Heat treatment to regulate bismuth valence toward enhanced radiation resistance in barium gallo‐germanate glass

et al. 2022

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“…As one of the tricolor phosphors for preparing n-UV W-LEDs, blue phosphors have always been widely studied. − However, the blue phosphors have mainly focused on rare-earth-doped systems (Eu 2+ , Ce 3+ ), such as BaAl 12 O 19 :Eu 2+ , RbNa 3 (Li 3 SiO 4 ) 4 :Eu 2+ , and NaK 2 Li[Li 3 SiO 4 ] 4 :Ce 3+ . In these systems, reabsorption in the visible light region due to their 4f–5d spin-allowed electronic transitions limits the improvement of high-quality W-LED lighting applications .…”

Section: Introductionmentioning

confidence: 99%

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

Liu

Peng

Fu³

et al. 2022

ACS Sustainable Chem. Eng.

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Since the strong blue light from the conventional blue chip has negative effects on human health, near-ultraviolet (n-UV) white light-emitting diodes (W-LEDs) have been widely studied. However, the photoluminescence spectrum generated by tricolor (blue, green, and red) phosphors contains a notable cavity in the deep-blue region (400−430 nm), which reduces the color quality. In this work, we report a novel series of narrow-band deepblue-emitting phosphors with strong n-UV excitation, Ln 2 Si 2 O 7 :Bi 3+ (Ln = Gd, Y, Lu, Sc), and realize the tuning of emission from 422 to 403 nm via cationic substitution, which bridges the deep-blue gap. All of these phosphors are effectively excited by n-UV radiation at approximately 370 nm and exhibit narrow-band deep-blue emission with a full width at half-maximum (FWHM) < 50 nm. Among them, Sc 2 Si 2 O 7 :Bi 3+ generates 403 nm deep-blue emission with a 38 nm FWHM under 372 nm n-UV excitation, with high luminescence intensity and excellent thermal stability. Finally, 365 nm n-UV-pumped phosphor-converted (pc) W-LED devices are fabricated by combining Sc 2 Si 2 O 7 :Bi 3+ and commercially available phosphors, and they have a high colorrendering index (Ra) of 95.4 and a low correlated color temperature (CCT) of 3736 K. This result suggests that these phosphors have potential applications in full-spectrum warm white lighting.

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“…Because the ionic radius of Bi 3+ in CN = 6 is R = 1.03 Å. [ 38 ] Therefore, the difference in ionic radius and coordination environment between Bi 3+ and Ba 2+ /Zn 2+ is relatively large, which limits the doping content of Bi 3+ ions in Ba 2+ lattice sites. When the doping content is low, the Bi 3+ ions can randomly occupy the Zn 2+ and Ba 2+ lattice sites, showing two emission peaks (425 and 590 nm).…”

Section: Resultsmentioning

confidence: 99%

Single Bi³⁺ Ultrabroadband White Luminescence in Double Perovskite via Crystal Lattice Engineering toward Light‐Emitting Diode Applications

Liu

Xiong

et al. 2022

Advanced Optical Materials

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Single‐phase white luminescence phosphors are emerging for potential phosphor‐converted white light‐emitting diodes (pc‐WLEDs) and alternatives to trichromatic phosphor blends. In this work, Ba2ZnWO6:Bi3+ phosphors are prepared by a high‐temperature solid‐state reaction method and the luminescent properties are investigated. The broadband excitation from 250 to 400 nm is perfectly matched with the emission of nearly ultraviolet (n‐UV) InGaN chip, which ultrabroadband emission band (full width at half maximum = 217 nm) can cover a wider luminescence region. Li+/Na+/K+ codoping is more desirable for the ultrabroadband emission of Ba2ZnWO6:0.006Bi3+ due to the charge compensation and rationally designed lattice distortion while improving the thermal stability of the phosphor. Furthermore, tunable emissions can be achieved either by changing the content of doped ions or the excitation wavelength due to the different occupation of Ba2+ and Zn2+ sites by Bi3+ ions. Finally, single‐phase warm WLED ((x, y) = (0.4170, 0.4035)) devices with a correlated color temperature of 3329 K and color rendering index of Ra = 75.3 are successfully prepared using Ba2ZnWO6:0.006Bi3+, 0.03Na+ phosphor, and 365 nm InGaN chips. These results indicate that Ba2ZnWO6:Bi3+ has excellent potential as phosphor for n‐UV pc‐WLEDs and provides new ideas for the application of ultrabroadband emitting phosphors in WLEDs.

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Bismuth activated blue phosphor with high absorption efficiency for white LEDs

Cited by 37 publications

References 66 publications

Heat treatment to regulate bismuth valence toward enhanced radiation resistance in barium gallo‐germanate glass

Heat treatment to regulate bismuth valence toward enhanced radiation resistance in barium gallo‐germanate glass

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

Single Bi³⁺ Ultrabroadband White Luminescence in Double Perovskite via Crystal Lattice Engineering toward Light‐Emitting Diode Applications

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Bismuth activated blue phosphor with high absorption efficiency for white LEDs

Cited by 37 publications

References 66 publications

Heat treatment to regulate bismuth valence toward enhanced radiation resistance in barium gallo‐germanate glass

Heat treatment to regulate bismuth valence toward enhanced radiation resistance in barium gallo‐germanate glass

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

Single Bi3+ Ultrabroadband White Luminescence in Double Perovskite via Crystal Lattice Engineering toward Light‐Emitting Diode Applications

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Single Bi³⁺ Ultrabroadband White Luminescence in Double Perovskite via Crystal Lattice Engineering toward Light‐Emitting Diode Applications