DALTON TRANSACTIONS
·
2020
·Vol. 49
·期 11
·3606-3614
·
IF 4.174
Yibing Wu,Yixi Zhuang,Rong-Jun Xie,Kaibin Ruan,Xinhua Ouyang
Red emitters based on CaAl12O19:Mn4+ have been attracting extensive attention due to their advantages of being rare-earth-free and chemically stable. However, their relatively low luminescence efficiencies will seriously hinder their application in light-emitting diodes (LEDs). In this regard, the promising red phosphors of CaAl12O19:Mn4+ were synthesized with enhanced luminous efficiency by introducing the coexisting phase of MgAl2O4. Importantly, an approximately 5 times enhancement of integrated intensity in the emission spectrum was observed for the phosphor with the coexisting phase compared to that with a single phase. Their crystal structures, morphologies and photoluminescence properties and the mechanism of improved luminescence were systematically investigated. Upon exciting them by using near-ultraviolet or blue LEDs, an efficient red emission was achieved with a maximum peak at ∼658 nm. In order to evaluate their potential application, a warm white LED and a plant growth LED were fabricated by using the prepared phosphors in combination with YAG:Ce3+ and InGaN-based blue chips.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry C
·
2017
·Vol. 5
·期 34
·8828-8835
·
IF 5.256
Yibo Chen,Kuanglun Wu,Jin He,Zhengbin Tang,Jianxin Shi,Yiqin Xu,Zhao-Qing Liu
The rational and delicate synthesis of Mn4+ activated red-emitting oxide phosphors with high photoluminescence quantum yield (PLQY) and photo-stability for developing high-quality w-LEDs still remains a great challenge. Herein, we demonstrate a simultaneous ion co-substitution design strategy to synthesize a red-emitting Lu3Al5O12:Mn4+,Mg2+ garnet phosphor delicately with the assistance of MgF2. The Mn4+ activated garnet phosphor exhibits superior moisture resistance properties and high PLQY (ca. 72.41%), which emits a bright and narrow-band red light peaking at ∼670 nm due to the 2E–4A2 spin-forbidden transition of Mn4+ upon UV excitation. Remarkably, MgF2 as a charge compensator & flux can not only accelerate the solid state reaction, but also greatly improve the emission intensity. Furthermore, by employing the as-prepared Lu3Al5O12:Mn4+,Mg2+ as a red component, we fabricate a warm w-LED with a high color rendering index (Ra = 81.4) and low color temperature (CCT = 4766 K) based on a UV chip and commercial blue and yellow phosphors.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Chemistry
·
2022
·
IF 7.613
B. Han,X. Yang,J. Ren,L. Liu,E. Zhao,X. Zhu,J. Zhu,H. Ma,A. Li,P. Teng
Indoor artificial cultivation of plants is a novel technology applied to agriculture, and the emission band of luminescent materials can be matched with the needs of plants to promote plant growth. In this contribution, novel Mn 4+ doped Sr 2 GdTaO 6 (SGTO) deep-red phosphor was synthesized. This material was characterized, in detail, by X-ray diffractometer, SEM, and photoluminescence emission spectra. Sr 2 GdTaO 6 :Mn 4+ (SGTO:Mn 4+ ) can be effectively excited by near-ultraviolet (NUV) light, and the broadband emission of deep-red light matches the absorption band of plant phytochromes P R and P FR . The optimum doping concentration of Mn 4+ in SGTO was 0.6 mol%, and the concentration quenching mechanism was attributed to dipole-quadrupole ( d - q ) electric interaction. The photoluminescence emission intensity of SGTO:0.006Mn 4+ at 423 K is 80.6% of that at room temperature and the internal quantum efficiency of SGTO:0.006Mn 4+ is 36.09%. Finally, the performance of the commercial 440 nm light-emitting diode chip/SGTO:0.006Mn 4+ encapsulated light-emitting diode device was stable and can meet the needs of plants for the blue and red light. The results showed that SGTO:0.006Mn 4+ deep-red phosphor is expected to be a phosphor suitable for indoor plant growth lighting.
研究领域:
农业科学
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材料科学
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光学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2019
·Vol. 102
·期 10
·5910-5918
·
IF 3.094
Renping Cao,Xinyan Lv,Yaqin Ran,Longxiang Xu,Ting Chen,Siling Guo,Hui Ao,Xiaoguang Yu
Li 5 La 3 Ta 2 O 12 :Mn 4+ (LLTO:Mn 4+ ) phosphors are prepared in air via high-temperature solid-state method and investigated for their crystal structures and luminescence properties. LLTO:Mn 4+ phosphor under excitation at 314 nm shows deep-red emission peaking at 714 nm due to the 2 E→ 4 A 2 transition of Mn 4+ ion. The excitation bands in the range 220 - 570 nm are attributed to the Mn 4+ - O 2- charge-transfer band and the 4 A 2g → 4 T 1g , 2 T 2g , and 4 T 2g transitions of Mn 4+ , respectively. The optimal Mn 4+ ion concentration is ~0.4 mol%. The concentration quenching mechanism in LLTO:Mn 4+ phosphor is electric dipole-dipole interaction. The luminous mechanism and temperature quenching phenomenon are explained by the Tanabe-Sugano energy level diagram and the configurational coordinate diagram of Mn 4+ in the octahedron, respectively. The experimental results indicate that LLTO:Mn 4+ phosphor has a potential application prospect as candidate of deep-red component in light-emitting diode (LED) lighting.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2015
·
IF 2.605
Renping Cao,Qingqiang Xiong,Wenjie Luo,Donglan Wu,Xiao Fen,Xiaoguang Yu
A series of SrAl [4−(4 x )/3] O 7 : x Mn 4+ (0≤ x ≤1.4 mol%) and Sr (1−0.06/2) Al [4−(4×0.008)/3] O 7 :0.008Mn 4+ ,0.06R + (R + =Li + , Na + , and K + ) phosphors are synthesized by a conventional solid-state reaction method in air. The PLE bands peaking at~325, 395, and 470 nm and the strongest PL band peaking at~660 nm are assigned to the 4 A 2 → 4 T 1 transition of Mn 4+ ion and O 2− –Mn 4+ change transfer band, 4 A 2 → 2 T 1 , 4 A 2 → 4 T 2 , and 2 E → 4 A 2 transitions, respectively. The optimum Mn 4+ doping concentration is about 0.8 mol%. Li + , Na + , and K + ions used as charge compensator can improve observably the PL intensity of SrAl 4 O 7 :Mn 4+ phosphor with excitation 325 nm. The fluorescence lifetimes of SrAl [4−(4×0.008)/3] O 7 :0.008Mn 4+ and Sr [1−0.06/2] Al [4−(4×0.008)/3] O 7 :0.008Mn 4+ ,0.06 R + (R + =Li + , Na + , and K + ) are 0.958, 0.97, 1.113 and 0.965 ms, respectively. The luminous mechanism is explained by schematic energy level diagram of Mn 4+ ion. These experiment results indicate that SrAl 4 O 7 :Mn 4+ ,R + (R + =Li + , Na + , and K + ) phosphors can be used as red emitting phosphor candidate for white LEDs based on a UV (~325 nm) and near UV (~395 nm) bands of LEDs chip.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2021
·Vol. 104
·期 10
·5077-5085
·
IF 3.784
Zhaowu Wang,Haipeng Ji,Zongtao Zhang,Jian Xu,Deliang Chen
The cation exchange method has been demonstrated to be efficient in doping Mn 4+ ions into various fluorides to synthesize the red-emitting LED phosphors. This paper, however, reports the challenge in using this method to dope Mn 4+ into the Na 2 SiF 6 single crystals, to prepare the fluoride phosphor in single-crystal form, a state-of-the-art study in the white LED lighting field. The millimeter-sized Na 2 SiF 6 single crystals with a uniform columnar morphology (2–3 mm in length) were successfully grown in solution by a slow cooling process after optimizing the precursors. Then, the crystals were soaked in the HF solution dissolved with K 2 MnF 6 to implement Mn 4+ -doping via the cation exchange process. Evaluation of the Mn 4+ -doping behavior reveals that the Mn 4+ ↔ Si 4+ cation exchange is less efficient in the case of single crystal host compared with the polycrystalline powdery ones and by-reactions also occur which generates new phases. The Na 2 SiF 6 single crystals doped with Mn 4+ exhibit a series of discrete sharp peaks with intense zero phonon line emission at 617 nm under 450 nm blue irradiation. This study may trigger the exploration of new single crystal fluoride phosphor.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2020
·Vol. 8
·期 18
·6299-6305
·
IF 7.059
Xinlong Dong,Yuexiao Pan,Yajun Jia,Rongjing Liu,Hongzhou Lian,Jun Lin
Mn4+-activated red phosphors have recently attracted tremendous attention for their fascinating performance in white light emitting diode (WLED) applications, achieving warm white light, while the thermal stability of fluorides 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 located 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 the reaction system. Partly substituting Ba2+ with Ca2+ decreases the luminescence 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) of 4796 K and a color rendering index (CRI) of 85.2 was obtained. The phosphor BSF:Mn remains undecomposed up to 800 °C; therefore, this work provides a strategy to explore a novel Mn4+-doped fluoride with particularly good thermal stability.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Wei Chen,Yinzi Cheng,Linli Shen,Chenyang Shen,Xiaojuan Liang,Weidong Xiang
To achieve efficient phosphors that address the shortage of red emission for use in white light emitting diodes (WLED), a series of red-emitting phosphors of Sr 2 MgGe 2 O 7 doped with different concentrations of Mn 4+ have been successfully fabricated by a high-temperature solid-state method. The crystal structure properties including the phase purity were analysed by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Absolute quantum yield, temperature stability, and lifetime were utilized to characterize the samples. Furthermore, the excitation spectra of the samples exhibit two broad absorption bands with peaks located at approximately 308 nm and 419 nm, which could be excited by near-UV/blue LED light. The emission spectra range from 600 nm to 700 nm and exhibited a sharp peak at 659 nm due to the 4 E→ 4 A 2 spin- and parity-forbidden transition of Mn 4+ . The optimal Mn 4+ doping concentration in the Sr 2 MgGe 2 O 7 host is determined to be 0.7%. The critical energy transfer distance of these phosphors is calculated to be about 26.61 Å, and the concentration quenching mechanism is proved to correspond to a dipole-dipole interaction. The luminescence of the Sr 2 MgGe 2 O 7 :Mn 4+ phosphors decrease gradually with increasing temperature, and the Sr 2 MgGe 2 O 7 :Mn 4+ sample exhibits better thermal stability than the commercial Sr 2 Si 5 N 8 :Eu 2+ red phosphors. The warm WLED is fabricated by combining the Sr 2 MgGe 2 O 7 :0.7%Mn 4+ and YAG:Ce 3+ phosphor with a 420-nm blue LED chip to explore its possible applications in warm WLED.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
LUMINESCENCE
·
2023
·Vol. 38
·期 9
·1562-1571
·
IF 2.9
Fadong Li,Yaosen Ye,Ruirui Cui,Jun Zhang,Cong Xu,Hui Xu,Gangyi Zhang,Chaoyong Deng
A series of Mn 4+ -doped and Mn 4+ ,K + -co-doped Ba 2 LaTaO 6 (BLT) double-perovskite phosphors was synthesized using a high-temperature solid-state reaction. The phase purity and luminescence properties were also studied. The optimum doping concentration of Mn 4+ and K + was obtained by investigating the photoluminescence excitation spectra and photoluminescence emission spectra. The comparison of BLT:Mn 4+ phosphors with and without K + ions shows that the photoluminescence intensity of K + -doped phosphors was greatly enhanced. This is because there was a charge difference when Mn 4+ ions were doped with Ta 5+ ions in BLT. Mn 4+ –K + ion pairs were formed after doping K + ions, which hinders the nonradiative energy transfer between Mn 4+ ions. Therefore, the luminescence intensity, quantum yield, and thermal stability of phosphors were enhanced. The electroluminescence spectra of BLT:Mn 4+ and BLT:Mn 4+ ,K + were measured. The spectra showed that the light emitted from the phosphors corresponded well with chlorophyll a and phytochrome P R . The results show that the BLT:Mn 4+ ,K + phosphors had good luminescence properties and application prospects and are ideal materials for plant-illuminated red phosphors.
研究领域:
材料科学
·
植物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ECS Journal of Solid State Science and Technology
·
2023
·Vol. 12
·期 7
·076018
·
IF 2.2
Xuan Gu,Xiao-Yu Sun,Zheng He
Mn4+ doped BaLa2Al2O7 phosphors were developed after a sintering process at 1400 °C for 3 h. The phase and luminescence performance of them were researched. The XRD patterns confirm single phase of the Mn4+ doped BaLa2Al2O7 phosphors. Upon the UV light excitation, the Mn4+ doped BaLa2Al2O7 phosphors emit strong deep-red emission. The concentration-dependence emission spectra demonstrate that the critical concentration for Mn4+ ion in BaLa2Al2O7 host is 0.006. On the basis of the temperature-dependence emission spectra, the activation energy for Mn4+ has been calculated as 0.292 eV, which suggests excellent thermostability of the Mn4+ activated BaLa2Al2O7 phosphors.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Yuanjing Wang,Yayun Zhou,Enhai Song
Mn 4+ -activated fluoride red phosphors have a bright prospect for improving the warm white light-emitting diodes (W-LEDs) performances, whereas there remains some challenges in synthesis, such as reducing the consumption of toxic HF and improving Mn 4+ doping efficiency. Herein, a new phosphor (NH 4 ) 2 NaScF 6 :Mn 4+ (NNSFM) was synthesized by an ammonium salt conversion method, which can effectively reduce HF consuming, enhance reaction rate and doping efficiency. The synthesis mechanism, luminescence properties and W-LEDs performances of the as-synthesized NNSFM have been investigated. Moreover, the lattice structure and doping position have been investigated in detail by the density functional calculations (DFT), which show that Mn 4+ could occupy the Sc 3+ crystallographic site in this structure and simultaneously produce a Na vacancy ( V Na ' ) for charge compensation. Using the NNSFM as red-light component, a warm W-LED device with a high color rendering index (CRI, Ra = 80.6) and low correlated color temperature (CCT = 3006 K) has been achieved. This work presents a new Mn 4+ doped fluoride red phosphor and also develops an environmentally friendly strategy for synthesizing Mn 4+ doped fluoride phosphors.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Yuanjing Wang,Yayun Zhou,Hong Ming,Yifei Zhao,Enhai Song,Qinyuan Zhang
Mn4+ non-equivalent doped fluorides with high color purity red emission and relatively short decay time are crucial for wide color gamut displays and emerging applications, whereas the low quantum efficiency (QE) restrains their further applications. Herein, the luminescence of Mn4+ non-equivalent doped fluoride K2NaAlF6:Mn4+ (KNAF:Mn4+) is significantly enhanced via a heterovalent co-doping strategy, where the luminescence intensity is obviously increased by ∼85%, but the decay time is almost unchanged. The experimental characterization and density functional theory (DFT) calculations provide an understanding of the luminescence enhancement mechanism of heterovalent co-doping, which is enabled by simultaneously improving the stability of Mn4+ and reducing the number of quenching centers (defects and impurities). Combining the short-decay-time (τ = 4.03 ms) emission KNAF:Mn4+, Mg2+ and long-decay-time (τ = 9.23 ms) emission K2SiF6:Mn4+, a novel monochromatic multiplexing mode in the millisecond order is presented, which can be decoded not only in high-efficiency by a digital camera but also with a high security. This work provides a new optical multiplexing for the information security applications and also inspires the design of high-efficiency Mn4+-activated luminescent materials.
研究领域:
材料科学
·
光学
·
信息科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）