- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
High concentration Eu3+-doped NaYb(MoO4)2 multifunctional material: Thermometer and plant growth lamp matching phytochrome PR
摘要： Phytochromes PR and PFR are distributed in various organs of plant, phytochrome PR absorbs red light and phytochrome PFR absorbs far-red light, respectively, so the flower induction, etc. can be controlled by changing the ratio of red light to far-red light. The emission of Eu3+ (transition from 5D0/7F2) is located at the red range and matches with the absorption band of PR. Herein, we synthesized successfully NaYb(MoO4)2: Eu3+ phosphors with the high doping concentration (50%) by hydrothermal method with further calcinations. The LED device was also fabricated by the blue InGaN chip combined with the red phosphors NaYb(MoO4)2: 50%Eu3+ based on the excellent luminescent intensity. Moreover, the effect of temperature on the excitation intensity ratio of MoO4 2- to Eu3+ has also been studied, which provided the possibility of simultaneous luminescence and temperature measurement. This work is the first time to use Eu3+ as a red source matching PR, and the red phosphors have potential value to control plant growth.
关键词： Down-conversion luminescence,Temperature sensing,LEDs,Plant cultivation,Red phosphors
更新于2025-09-23 15:22:29
-
Photoluminescence Characteristics of Sm3+-doped LnBWO6 (Ln=La, Gd and Y) as New Orange-red Phosphors
摘要： A series of Sm3+-doped LnBWO6 (Ln=La, Gd and Y) phosphors with orange-red light emitting in pure phase were prepared by high temperature solid-state process. The crystal structure, photoluminescence properties, decay lifetimes and thermal stability properties of those as-prepared samples were investigated. Those phosphors can be efficiently excited by near-UV and blue light and emitted orange-red luminescence with color coordinates (0.622, 0.377). Among those LnBWO6 (Ln=La, Gd and Y) hosts, the emission intensities of Sm3+-doped LaBWO6 are the strongest ones. The optimum doping concentration and critical energy transfer distance of Sm3+ ions in LaBWO6 were determined. The fluorescence concentration quenching mechanism was attributed to the dipole-dipole interaction between the Sm3+ ions. The fluorescent thermal quenching studies showed Sm3+ doped LaBWO6 had high thermal-stable properties. The present work suggested that Sm3+-doped LnBWO6 (Ln=La, Gd and Y) as orange-red phosphors exhibited potential application in white LED.
关键词： red phosphors,concentration quenching,energy transfer,white LEDs,luminescent properties
更新于2025-09-23 15:22:29
-
Enhanced deep-red emission from Mn <sup>4+</sup> /Mg <sup>2+</sup> co-doped CaGdAlO4 phosphors for plant cultivation
摘要： Mn4+ doped oxide phosphors are under intensive investigation owing to their low manufacture cost and attractive luminescent features for indoor plant cultivation applications. However, it is still a challenge to develop Mn4+ doped oxides with high luminescence efficiency and thermal stability. Herein, Mn4+-Mg2+ pairs are incorporated into a CaGdAlO4 host to reduce non-radiative channels formed by Mn4+-Mn4+-O2- clusters. The photoluminescence and quantum efficiency are significantly enhanced after the introduction of Mg2+ ions to the host. A prolonged Mn4+ decay time is also obtained from the Mn4+/Mg2+ co-doped samples. Intense red emission with a narrow peak at 712 nm due to the 2Eg → 4A2g transition of Mn4+ ions is observed under 335 nm excitation. The LED fabricated by coating the synthesized phosphor on a 365 nm near-UV chip exhibit intense deep red emission with CIE chromaticity coordinates of (0.712, 0.285). The results indicate the Mn4+/Mg2+ co-doped CaGdAlO4 phosphors may be applied to the plant cultivation fields.
关键词： red phosphors,plant cultivation,LEDs,photoluminescence,Mn4+
更新于2025-09-19 17:15:36
-
Effects of Gd3+ codoping on the enhancement of the luminescent properties of a NaBi(MoO4)2:Eu3+ red-emitting phosphors
摘要： A series of NaBi(MoO4)2:Eu3+ and NaBi(MoO4)2:Eu3+, Gd3+ phosphors were prepared using a sol-combustion method. NaBi(MoO4)2:Eu3+ with a tetragonal scheelite structure was obtained by heat treatment at 600–800 °C. The effects of the synthetic temperature and Eu3+ concentration on the luminescent properties of the NaBi(MoO4)2:Eu3+ phosphors were investigated. Under blue excitation at 464 nm, the NaBi(MoO4)2:Eu3+ sample exhibited a strong red emission peak at 618 nm, which originated from the 5D0→7F2 transition of Eu3+. Furthermore, Gd3+ ions were codoped into NaBi(MoO4)2:Eu3+ to enhance the luminescent intensity of NaBi(MoO4)2:Eu3+, Gd3+ due to energy transfer between Gd3+ and Eu3+. The results indicated that the NaBi(MoO4)2:Eu3+, Gd3+ red phosphor could be applied to white light-emitting diodes to achieve excellent properties, such as a high color rendering index and low correlated color temperature.
关键词： NaBi(MoO4)2,Energy transfer,Luminescence enhancement,Codoping,Red phosphors
更新于2025-09-19 17:15:36
-
Elucidating the structure and optimising the photoluminescence properties of Sr2Al3O6F: Eu3+ oxyfluorides for cool white-LEDs
摘要： Herein, Sr2Al3O6F in hexagonal symmetry was synthesized via a solid-state methodology. The X-ray diffraction pattern of Sr2Al3O6F was refined by the Rietveld refinement with lattice parameters a = 17.8232(1) ? and c = 7.2168(0) ?. The stability of the crystal structure is further confirmed from the results of bond valence sums and the global instability index. The theoretical calculations of the electronic and optical behaviors of the Sr2Al3O6F were analyzed by density functional theory and the obtained results of the lattice parameters and direct bandgap were found close to the experimental data. The chemical states and elemental composition of Sr2Al3O6F were also authenticated by X-ray photoelectron spectroscopy (XPS). To evaluate the suitability of the Sr2Al3O6F structure as high efficient red phosphor, a series of Eu3+ doped Sr2-xEuxAl3O6F (x = 0.0 to 0.10) were synthesized, which showed intense red-orange emission (5D0→7F1,2) at UV and blue excitations. The photoluminescence intensity corresponding to 5D0→7F2 transition decreased significantly for x = 0.10 due to the luminescence quenching. Nevertheless, further enhancement in photoluminescence of Sr1.9Al3O6F: Eu0.1 sample was realized with the substitution of 0.1 mol Ba2+ ion for 0.1 mol Sr2+ ion. The various radiative properties of the emission bands were also analyzed through the Judd-Ofelt theory. The optimized Sr1.8Al3O6F: Ba0.1/Eu0.1 phosphor showed high red color purity (> 95%), and moderate thermal stability of around 72% at 150 oC, suggesting that it could be an ideal red component for white-LEDs. A white-LED comprising the commercial yellow phosphor and the optimized sample showed bright white light having the CRI of 80.5%, CCT of 5510 K, and CIE of (0.33, 0.36) indicating that Sr1.8Al3O6F: Ba0.1/Eu0.1 phosphor is an appropriate red component for cool white-LEDs.
关键词： Eu3+-doping,Rietveld refinement,Hexagonal Sr2Al3O6F,density functional theory,white-LEDs,red phosphors
更新于2025-09-19 17:13:59
-
Improved luminescence properties of a novel red dodec-fluoride phosphor Ba <sub/>3</sub> Sc <sub/>2</sub> F <sub/>12</sub> :Mn <sup>4+</sup> with extraordinary thermal stability for WLED application
摘要： Mn4+-activated red phosphors have recently attracted tremendous attention for their fascinating performance in white light emitting diodes (WLEDs) application to achieve warm white light, while the thermal stability of fluoride is still considered as a drawback. Herein, we report a novel red phosphor composed of Ba3Sc2F12:Mn4+ (BSF:Mn), in which, the emitting centers of Mn4+ ions are locating in the sites of Sc3+ ions. The photoluminescence of BSF:Mn varies with the concentration of K2MnF6, reaction temperature, and the concentrations of NH3·H2O in reaction system. Partly substituting Ba2+ with Ca2+ decreases the luminescent intensity of BSF:Mn. By employing the as-prepared phosphor BSF:Mn as a red component, a high-performance WLED with a correlated color temperature (CCT) at 4796 K and a color rendering index (CRI) of 85.2 was obtained. The phosphor BSF:Mn keeps undecomposed up to 800 oC, therefore, this work exhibits a strategy to explore a novel Mn4+-doped fluoride with particularly thermal stability.
关键词： luminescent properties,thermal stability,Ba3Sc2F12:Mn4+,Mn4+-activated red phosphors,WLEDs
更新于2025-09-19 17:13:59
-
Transition metal ion Co-Doped MgO–MgF2-GeO2:Mn4+ red phosphors for white LEDs with wider color reproduction gamut
摘要： Mn4+-activated non-rare-earth based red phosphors are excellent down conversion materials for phosphor-converted light-emitting diode (pc-LEDs) based solid-state lighting applications. However, the low quantum efficiency of Mn4+ activated red phosphors under InGaN based blue LED excitation hinders their use in phosphor-converted LEDs. To enhance the absorption at an excitation wavelength of around 420 nm in Mn4+-doped MgO-MgF2-GeO2 (MGF: Mn4+), which is a conventional red-emitting lamp phosphor, we doped MGF: Mn4+ phosphors with transition metal oxides (Sc2O3, Lu2O3, Y2O3, and La2O3) replacing MgO. When excited using 420 nm light, the absorption ratio of the synthesized phosphors with Sc2O3 (Sc-MGF:Mn4+) was 58% with an internal quantum efficiency (IQE) of 55% as compared to the 35% IQE of the pristine MGF-Mn4+ phosphor. White LEDs were fabricated using Sc-MGF-Mn4+ (red), and β-SiAlON:Eu2+ (green) on InGaN chips (λem = 450 nm) and their performance was compared to the optical performance of LEDs fabricated using K2SiF6:Mn4+ as the red phosphor. According to the National Television System Committee (NTSC) standard, the color reproduction coverage with an Sc-MGF:Mn4+ phosphor-loaded white LED was 121% by the International Commission on Illumination (CIE) 1976, and 80% by the BT.2020 standard. The coverages are 9% and 6% higher than the coverages of LEDs fabricated using K2SiF6:Mn4+ as the red phosphor according to the NTSC and BT.2020 standards, respectively. Our simple approach to enhance the IQE of Mn4+ activated phosphors by co-doping transition metal oxides can be extended to other Mn4+ activated phosphor systems for applications that require enhanced absorption, higher luminescent emission intensity, and a wider gamut of color reproduction.
关键词： MgO-MgF2-GeO2,Mn4+ activated red phosphors,Solid-state lighting,White LEDs,BT.2020
更新于2025-09-12 10:27:22