OPTICAL MATERIALS
·
2020
·
IF 2.779
Lu Chen,Fang Lei,Haohong Chen,Luqiao Yin,Ding Zhou,Ying Shi,Teng Ma
A novel Eu 3+ doped SiO 2 -B 2 O 3 -Al 2 O 3 -CaO-Na 2 O based borosilicate glass was designed to embed YAG: Ce for PiGs. It exhibits intense Eu 3+ red emission with the average decay times of 6.8 μs and has the thermal conductivity of about 0.9 W/(mK) (five times that of silicone resin). The doped Eu 3+ is over 10 mol% without any concentration quenching. The PiGs show variable decay time of Ce 3+ , which results from the tunable interface defects explained by the pseudo-solid solubility mechanism. The color of the WLEDs changes from cool white (6004 K) to warm white (3799 K) with more yellow emission added. The obtained maximal luminous efficiency and color rendering index are about 68 lm/W and 78, respectively. The anti-thermal quenching power of the PiGs is three times that of PiS based on the luminescent reduction. The PiG system can be used potentially for resin-free high power WLEDs.
研究领域:
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
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Wei Wang,Hang Yang,Meiqian Fu,Xinyang Zhang,Mengyu Guan,Yi Wei,Chun Che Lin,Guogang Li
Thermal quenching is still a pivotal challenge for phosphor materials in white light emitting diodes lighting applications. Herein, we propose an effective strategy to design a near zero-thermal-quenching green emission in zero-thermal-expanding Zn 4 B 6 O 13 host based on unique 3D isotropic cage structure. The integrated emission intensity of Zn 4 B 6 O 13 :Mn 2+ could maintain 103% of initial intensity at 150 °C and 98% at 250 °C under blue light excitation. During the low-frequency vibrations, the unchanged bonds and angles induce the zero thermal expansion, and the unaffected lattice and coordination environment contribute the nearly unchanged emission intensity during the heating process. In addition, an efficient self-reduction of activators in the studied system is ascribed to vacancy and interstitial oxygen defects act as donors to provide electrons. This work initiates a novel strategy to construct thermally-stable and self-reductive phosphors for multiple optical applications.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 18
·6220-6226
·
IF 6.4
Dayu Huang,Ziyong Cheng,Qiuyun Ouyang,Hongzhou Lian,Jun Lin
The lattice defects that occur in material preparation processes are closely related to carrier migration. The carrier migration can be regulated by artificially modulating the defects to improve the luminescence performance, which is important for the development and application of luminescent materials. Here, we achieved a 3.29-fold increase in the high-temperature luminescence intensity by introducing Mn2+ to generate Cl vacancy defects in Cs2CdCl4. Due to thermally induced electron de-trapping, Cs2CdCl4:Mn2+ also displays anti-thermal quenching (ATQ) behavior and good thermal quenching resistance (329% at 175 °C). The increase in the photoionization effect and de-trapping of the captured electrons from shallow trap states were appropriately attributed to this exceptional phenomenon, based on thermoluminescence (TL) analysis. Based on comprehensive optical characterization, thermoluminescence and temperature-dependent X-ray diffraction (XRD), we reveal that the Cl vacancy trap state generated by Mn doping is the reason for the enhanced PL in air. The discovery of these materials helps to better understand the optical properties of all-inorganic perovskites.
研究领域:
材料科学
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光学
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2024
·
IF 4.3
Shaokun Ling,Yaxiong Wang,Xiaoyan Qin,Chang Chen,Chunchun Lu,Jidong Chen,Sen Liao,Yingheng Huang,Lei Hou
Although being applied in various fields, white light emitting diodes (WLEDs) still have drawbacks that urgently need to be conquered: the luminescent intensity of commercial phosphors sharply decreases at working temperature. In this study, we calculated the forming energy of defects and confirmed that the VNa defect state can stably exist in β-NaGdF4, by density functional theory (DFT) calculation. Furthermore, we predicted that the VNa vacancies would provide a zero thermal quenching (ZTQ) property for the β-NaGdF4-based red-light phosphor. Then, a series of β-NaGdF4:xEu3+ and β-NaGdF4:0.25Eu3+,yYb3+ red-light phosphors were synthesized by the hydrothermal method. We found that β-NaGdF4:0.25Eu3+ and β-NaGdF4:0.25Eu3+,0.005Yb3+ phosphors possess ZTQ properties at a temperature range between 303–483 K and 303–523 K, respectively. The thermoluminescence (TL) spectra were employed to calculate the depth and density of the VNa vacancies in β-NaGdF4:0.25Eu3+ and β-NaGdF4:0.25Eu3+,0.005Yb3+. Combining the DFT calculation with characterization results of TL spectra, it is concluded that electrons stored in VNa vacancies are excited to the exited state of Eu3+ to compensate for the loss of Eu3+ luminescent intensity. This will lead to an increase of luminescent intensity at high temperatures and facilitate the samples to improve ZTQ properties. WLEDs were obtained with CRI = 83.0, 81.6 and CCT = 5393, 5149 K, respectively, when phosphors of β-NaGdF4:0.25Eu3+ and β-NaGdF4:0.25Eu3+,0.005Yb3+ were utilized as the red-light source. These results indicate that these two phosphors may become reliable red-light sources with high antithermal quenching properties for WLEDs.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Liangjun Zhou,Wenxi Wang,Dekang Xu,Zhenyu Wang,Zhibin Yi,Min Wang,Zhouguang Lu
Thermal quenching of luminescence is the most critical problem for rare earth doped phosphors used in light-emitting diodes (LEDs). Herein, we demonstrate that thermal quenching can be considerably suppressed via the negative thermal expansion effect in Zr(WO 4 ) 2 that serves as host for Eu 3+ red emission. The photoluminescence (PL) intensity is surprisingly enhanced by 130% when the temperature is raised from room temperature to 100 °C. As temperature further increases to 160 °C, the PL intensity turns to reduce, which is still 1.4 times of that at room-temperature. Moreover, Zr(WO 4 ) 2 :15%Eu phosphor has good durability, which still exhibits strong red luminescence (only 13% loss) after being kept in 85 °C/85% relative humidity chamber for 240 h. The anti-thermal quenching of Eu 3+ luminescence can be ascribed mainly to the following two factors: first one is the thermal-enhanced energy transfer between Eu 3+ ions induced by the contraction of Zr(WO 4 ) 2 unit-cell volume that leads to the strong structural rigidity of host lattice; second one would be electron traps in the host that favors the increase of electrons on the excited energy levels. This important anti-thermal quenching effect induced from the negative thermal expansion of the host matrix may stimulates a novel and efficient approach to design highly thermal stable phosphors for next-generation LEDs.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Nature Communications
·
2025
·Vol. 16
·期 1
·1-11
·
IF 15.7
Suo Hao,Zhao Peihang,Zhang Xin,Guo Yang,Guo Dongxu,Chang Jiwen,Chen Jiangkun,Li Panlai,Wang Zhijun,Wei Hanlin,Zheng Weilin,Wang Feng
Lanthanide-doped nanocrystals are promising for photon frequency upconversion with substantial spectrum tunability. However, the utilization of the upconversion process has been constrained by low luminescence efficiency, which may further attenuate at elevated temperatures due to thermal quenching. Herein, we report a versatile strategy to boost upconversion luminescence across a wide temperature range by surface coordination of small organic molecules. Mechanistic investigations affirm that the organic surface layer passivates defects and isolates high-energy surface oscillators, thereby preventing the dissipation of excitation energy. The energy preserving effect becomes more prominent with increasing temperatures, especially in a humid environment. Accordingly, the upconversion emission of NaGdF 4 :Yb 3+ /Tm 3+ nanocrystals is substantially enhanced in the ambient environment after ligand coordination, accompanied by an additional emission augmentation with increasing temperature to 443 K. By leveraging this anomalous optical response to thermal stimuli, we further establish full-color thermochromic upconversion switching for advanced anti-counterfeiting and logic encryption technologies.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
OPTICAL MATERIALS
·
2023
·
IF 3.9
Lifang Wu,Jun Wang,Wenzhi Wu
In this work, photoluminescence (PL) intensity and stability of CsPbBr 3 /PbBrOH powders synthesized by one-pot method are enhanced through the encapsulation of poly (vinyl acetate) (PVA) in water. Understanding the function of PbBrOH and PVA matrix for photogenerated transition can be achieved through temperature-dependent steady-state and time-resolved PL. The enhanced PL quantum yield (65.9%) and longer lifetime indicate the strengthened structural stability and a significant reduction in nonradiative recombination of CsPbBr 3 . Negative thermal quenching can be observed and interpreted using a multilevel PL transition model. Through nanosecond time-resolved PL spectra under femtosecond laser excitation, it is revealed that the PL position shows a redshift (∼8 nm) with time delay due to the reduction of band-filling effect during the recombination of photoexcited carriers. PVA further encapsulates CsPbBr 3 /PbBrOH powders to form a flexible film, which exhibits excellent thermal and water stability due to the dual protective effects of PVA and PbBrOH. The experimental investigation demonstrates that CsPbBr 3 encapsulated by PbBrOH and PVA possesses excellent luminescent and water-resistant characteristics, making it a new choice for practical applications in LEDs and screen printing.
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 LUMINESCENCE
·
2020
·
IF 3.28
Yaochun Qiang,Yanan Liu,Jiayuan Chen,Shaopeng Liu,Lulu Zhang,Haojian Kang,Feiyan Xu,Zongliang Xiao,Weixiong You,Lei Han,Xinyu Ye
It is well known that green-emitting phosphor plays a key role in a phosphor-converted white LED with high color rendering index. Here, a novel green phosphor BaY 1·95 Al 2 Ga 2 SiO 12 :0.05Ce 3+ with high quantum yield , low thermal quenching and excellent water resistance is reported. The green phosphor can be easily prepared by the conventional solid-state reaction method at 1325 °C for 4 h in a reducing atmosphere. The compound is cubic and crystallizes in space group I a 3 ‾ d with refined lattice parameters of a = 12.1451(3) Å. The phosphor can be effectively excited by the mainstream commercial blue LEDs (445–465 nm), its emission peak is observed at 517 nm and the absolute quantum yield under 450 nm excitation is as high as 96.2% at 25 °C. The green phosphor exhibits good resistance toward thermal quenching, with the luminescence intensity at 150 °C only decreasing by 11% of the value at 25 °C. In addition, the green phosphor has a very good water resistance, and its luminescence intensity remains almost unchanged when it is soaked in water for more than 300 h. The white LED fabricated by employing the green phosphor shows excellent optical properties with Ra = 92.4, CCT = 3304 K and CIE 1931 chromaticity coordinates as (x = 0.4178, y = 0.3985). All experimental results indicate that BaY 1·95 Al 2 Ga 2 SiO 12 :0.05Ce 3+ is an outstanding green phosphor which has great potential to be used for the phosphor-converted white LEDs with excellent color rendering.
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
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Jianxu Wang,Yan Xie,Junlan Guo,Xuemei Yao,Xue Geng,Jing Gao,Xuyao Feng,Zijing Zhou,Yuanyuan Liu,Bin Deng,Ruijin Yu
Novel apatite-type NaCa 3 Bi(PO 4 ) 3 F: x Sm 3+ (0.01 ≤ x ≤ 0.30) orange-red-light phosphors were synthesized through the solid-state method at high temperature. The crystal structure, energy band structure , density of state, phase purity, particle morphology , photoluminescence properties, thermostability, and luminescence decay of the phosphors were comprehensively characterized. When λ ex = 404 nm, the optimal NaCa 3 Bi(PO 4 ) 3 F:0.05 S m 3+ phosphor showed the orange-red emission (597 nm). The NaCa 3 Bi(PO 4 ) 3 F:Sm 3+ phosphors exhibited abnormal thermal quenching properties as their emission intensity increased by about 2.57% from 300 to 380 K. Their intensity at 440 K was still 1.01-fold stronger than that at room temperature. The abnormal thermal quenching mechanisms were well explained via the coordinate configuration scheme. The thermal activation energy ( E a ) was calculated to be 0.79 eV. The color purity of all the phosphors reached 99.9%. Ultimately, a white light-emitting diode (w-LED) was fabricated based on the tri-color RGB method. The color rendering index and the chromaticity coordinates of the fabricated w-LED were 89 and (0.310, 0.319), respectively. Thus, these high thermostability NaCa 3 Bi(PO 4 ) 3 F:Sm 3+ orange-red phosphors can be potentially used in w-LED applications.
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
MOLECULES
·
2025
·Vol. 30
·期 9
·1945
·
IF 4.6
Zaifa Yang
In recent years, rare earth ion and transition metal ion co-doped fluorescent materials have attracted a lot of attention in the fields of WLEDs and optical temperature sensing. In this study, I successfully prepared the dual-emission Mg3Ga2SnO8:Eu3+,Mn4+red phosphors and the XRD patterns and refinement results show that the prepared phosphors belong to the Fd-3m space group. The energy transfer process between Eu3+and Mn4+was systematically investigated by emission spectra and decay curves of Mg3Ga2SnO8:0.12Eu3+,yMn4+(0.002 ≤ y ≤ 0.012) phosphors and the maximum value of transfer efficiency can reach 71.2%. Due to the weak thermal quenching effect of Eu3+, its emission provides a stable reference for the rapid thermal quenching of the Mn4+emission peak, thereby achieving good temperature measurement performance. The relative thermometric sensitivities of the fluorescence intensity ratio and fluorescence lifetime methods reached a maximum value of 2.53% K−1at 448 K and a maximum value of 3.38% K−1at 473 K. In addition, the prepared WLEDs utilizing Mg3Ga2SnO8:0.12Eu3+phosphor have a high color rendering index of 82.5 and correlated color temperature of 6170 K. The electroluminescence spectrum of the synthesized red LED device by Mg3Ga2SnO8:0.009Mn4+phosphor highly overlaps with the absorption range of the phytochrome PFRand thus can effectively promote plant growth. Therefore, the Mg3Ga2SnO8:Eu3+,Mn4+phosphors have good application prospects in WLEDs, temperature sensing, and plant growth illumination.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Chunyang Zhang,Yifan Wang,Zexiong Wang,Shilong Zhao,Ruoshan Lei,Shiqing Xu
The development of ultrasensitive thermometric phosphors has become an active area of research due to their appealing applications in the contactless temperature detection field. Herein, the scheelite-related compounds—CaGd 2 (WO 4 ) 4 : Nd 3+ , Yb 3+ and CaGd 2 (MoO 4 ) 4 : Nd 3+ , Yb 3+ , which exhibit high sensing capacity—are successfully prepared and systematically characterized. The X-ray diffraction analysis reveals that CaGd 2 (WO 4 ) 4 : Nd 3+ , Yb 3+ exhibits the monoclinic structure, whereas CaGd 2 (MoO 4 ) 4 : Nd 3+ , Yb 3+ is in the tetragonal phase. The maximum phonon cut-off energy of CaGd 2 (WO 4 ) 4 : Nd 3+ , Yb 3+ is 929 cm −1 , slightly larger than that of CaGd 2 (MoO 4 ) 4 : Nd 3+ , Yb 3+ (904 cm −1 ). Irradiated by 980 nm laser, PL spectra consist of the Nd 3+ : 4 F j → 4 I 9/2 (j = 7/2, 5/2, 3/2) and Yb 3+ : 2 F 5/2 → 2 F 7/2 emissions located in the near-infrared (NIR) range. Negative and positive thermal quenching behaviors are observed for the emissions of Nd 3+ (754, 802, and 868 nm) and Yb 3+ (1008 nm), respectively, attributed to the cooperative effects of the phonon-assisted energy transfer process of Yb 3+ → Nd 3+ and excited state absorption process of Nd 3+ . Moreover, the host material can affect the luminescence properties, thermal enhancement factor of the NIR anti-Stokes emission, and thermal sensing performance of the Nd 3+ -Yb 3+ pair. Consequently, CaGd 2 (MoO 4 ) 4 : Nd 3+ , Yb 3+ exhibits higher sensing sensitivity (S r-max = ∼6.00%K −1 ) than CaGd 2 (WO 4 ) 4 : Nd 3+ , Yb 3+ (S r-max = ∼5.56%K −1 ). This study provides useful information for the construction of high-performance ratiometric thermometers based on the inverse thermal dependence of the NIR emissions of Nd 3+ and Yb 3+ ions.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2022
·
IF 10.508
Chaojie Li,Jiyou Zhong
Broadband near-infrared (NIR) light source based on phosphor-converted light-emitting-diode (pc-LED) is crucial for applications in medical diagnosis, food quality analysis, and night vision fields, motivating the development of highly efficient and thermal robust NIR phosphor materials. Herein, a novel Cr3+-doped garnet phosphor Y3In2Ga3O12:Cr3+ emerges from a fundamental study of the Ln3In2Ga3O12 (Ln = La, Gd, Y, and Lu) family. Upon 450 nm excitation, this material presents a broadband NIR emission covering 650–1100 nm with a peak located at 760 nm and a full width at half maximum of 125 nm. This material also possesses an ultrahigh internal quantum efficiency (IQE = 91.6%) and absorption efficiency (AE = 46.6%), resulting in an external quantum efficiency as high as 42.7%. Moreover, the emission intensity of this material at 150 °C maintains 100% of the initial intensity, showing a rare zero-thermal-quenching property. Fabricating an NIR pc-LED device by using this material, an excellent NIR output power of 68.4 mW with a photoelectric efficiency of 15.9% under 150 mA driving current can be obtained, which exhibits much better performance than the devices fabricated by using some reported efficient NIR materials. Therefore, this work not only provides an ultraefficient and thermally robust broadband NIR material for spectroscopy application but also contributes to the foundation of design rules of NIR materials with high performance.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）