Article
Materials Science, Multidisciplinary
Yun Tang, Ben Liu, Nan Yan, Xiaoqiang He, Hudie Yuan, Yalou Xin, Hongfeng Yin
Summary: In this study, red-emitting MAPbBr(3-x)I(x) QDs-coated YAG:Ce (A-YAG@QDs) composites were successfully prepared to fabricate WLED with compensated red emission. The dispersion and sinking-related issues between QDs and YAG:Ce were effectively avoided through chemical coordination interactions. The resulting WLED exhibited warm white light with low CCT, high Ra, and high value of saturated red color component R9, making it suitable for indoor lighting applications.
Article
Computer Science, Information Systems
Naiqi Pei, Xuan Yang, Bin Xie, Xiaobing Luo
Summary: This study investigates the variation in photothermal parameters of QD-WLEDs during aging and analyzes the effects of QDs and the LED package on their optical performance. Different optimization strategies for optical quality and lifetime in LED design process are proposed based on optical and thermal analysis.
Article
Chemistry, Multidisciplinary
Zishan Yan, Tong Chen, Lingpeng Yan, Xinghua Liu, Jingxia Zheng, Fu-de Ren, Yongzhen Yang, Bin Liu, Xuguang Liu, Bingshe Xu
Summary: White-light emitting carbon dots (WCDs) with high color rendering index (CRI) were prepared through a one-step solvothermal reaction. The WCDs emit white light by combining red, yellow, green, and blue lights. The high CRI value of 97 achieved in WLEDs using the WCDs as phosphors is among the highest reported. Additionally, multicolor LEDs can be fabricated using the four multicolor CDs as phosphors.
Article
Optics
Mengna Yin, Xiaozhen Wei, Yanqin Miao, Di Zhang, Guoliang Wang, Huixia Xu, Hua Wang, Fei Chen
Summary: A novel and ultra-simple all fluorescent di-chromatic white organic light-emitting diodes (WOLEDs) with high color rendering index and color stability have been achieved by using only three non-doped organic layers. The emission spectra could be easily improved by changing the thickness of the charge adjusting layer.
JOURNAL OF LUMINESCENCE
(2021)
Article
Engineering, Electrical & Electronic
Xuehua Shen, Huanting Chen, Wenjie Zhang, Xiaoxi Ji, Yan Yi
Summary: This paper focuses on dynamic dimming for phosphor-converted (PC) white LEDs to achieve adjustable correlated color temperature (CCT) and adequate color rendering index (CRI) by compensating for red/green spectra. The proposed tunable dimming models involve multi-physics effects and the nonlinear characteristics are observed. Experimental verifications show good agreement between calculations and measurements, indicating the effectiveness of the proposed models in understanding photometric characteristics and visual perception of illumination.
IEEE PHOTONICS JOURNAL
(2023)
Article
Materials Science, Multidisciplinary
S. C. Hong, S. T. Gwak, S. Park, G. J. Lee, J. -G. Lee, J. -H. Ko, S. Y. Joe, Y. Kim, T. Park, Y. W. Ko
Summary: The study demonstrates that the use of red quantum dot films can enhance the color-rendering properties of white light-emitting-diodes (LEDs) modules, leading to an improved overall color rendering index (CRI). The design of quantum dot films and optical cavities plays a crucial role in enhancing both the efficiency and color rendering properties of LED lighting.
CURRENT APPLIED PHYSICS
(2021)
Article
Engineering, Environmental
Suk-Young Yoon, Yang-Hee Kim, Dae-Yeon Jo, Jung-Ho Jo, Sun-Hyoung Lee, Hyun-Min Kim, Yuri Kim, Sun-Kyo Kim, Heesun Yang
Summary: Metal chalcogenide I-III-VI quantum dots have shown promising potential for optoelectronic applications due to their environmentally friendly composition, high fluorescence, and compositional flexibility. By using highly reactive anionic sources and varying the nominal x values, multinary Zn-Cu-Ga-Se1-xSx QDs with emission tunability from blue to deep red were efficiently synthesized in this work. The resulting QDs exhibited high photoluminescence quantum yields and were utilized in the fabrication of a high-performance white lighting non-Cd QD-light-emitting diode, achieving exceptional color rendering index and peak luminance.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Materials Science, Multidisciplinary
Hsiang-Ling Shen, Jiun-Yi Lien, Chin-Wei Lu, Zu-Po Yang, Hai-Ching Su
Summary: Low-color-temperature white light-emitting electrochemical cells (LECs) based on mixed CdZnSeS/ZnS quantum dots (QDs) and an ionic transition metal complex (iTMC) carrier injection layer are demonstrated. These white LECs exhibit white electroluminescence (EL) with a low correlated color temperature (CCT) < 1800 K and a high color rendering index (CRI) > 90 under lower currents. Removing the blue QDs from the white QD LECs not only prevents the CCT from increasing under a higher device current but also improves the device efficiency.
ORGANIC ELECTRONICS
(2023)
Article
Materials Science, Multidisciplinary
Hao Liu, Zhongwen Li, Feng Nan, Rongfang Feng, Zhengzhong Zhang, Yongfu Liu
Summary: This study investigated a cyan phosphor with a suitable excitation wavelength and high thermal stability, which plays a key role in color conversion in white LEDs. The phosphor exhibits a high internal quantum efficiency and excellent thermal stability.
MATERIALS RESEARCH BULLETIN
(2023)
Article
Materials Science, Ceramics
Ruitong Song, Zhiqin Yang, Hongzhi Zhang, Xiaoqin Tang, Yuxin Liu, Jing Zhu
Summary: To solve the problem of inefficient excitation of Eu3+-activated red phosphors at -365nm, a color-tunable phosphor Na3Ca4(TeO3)(PO4)3 (NCTP):Dy3+,Eu3+ was prepared using the energy transfer between Dy3+ sensitizer and Eu3+ activator. Under 363nm excitation, the luminous color was adjusted to red due to the efficient Dy3+-> Eu3+ energy transfer controlled by dipole-dipole interaction. Moreover, the introduction of Dy3+ sensitizers enhanced the structural rigidity and resulted in high luminescence thermostability.
CERAMICS INTERNATIONAL
(2023)
Article
Optics
Wei Li, Nan Ma, Balaji Devakumar, Xiaoyong Huang
Summary: This study presents a new efficient blue-light-excited Ce3+-doped CaY2HfScAl3O12 green phosphor with broad emission bandwidth and high quantum efficiency. The potential application of this phosphor in fabrication of full-spectrum LED lighting is demonstrated.
JOURNAL OF LUMINESCENCE
(2023)
Article
Chemistry, Multidisciplinary
Seung Chan Hong, Jae-Hyeon Ko
Summary: By studying a remote-type white LED, which consisted of a red quantum-dot film and a yellow phosphor plate, it was found that the sequence of the two color-conversion films had a significant impact on the color-rendering properties. The optimized configuration showed a high color rendering index of more than 90, thanks to the enhanced red component via the quantum-dot film. For the design of high-power white LED devices, it is necessary to place the color-conversion films below the diffuser plate to eliminate color dispersion depending on the viewing angle. These findings suggest that high-power and high color-rendering white LED devices can be achieved using two vertically-stacked color-conversion materials, providing long-term stability due to the remote design.
Article
Chemistry, Multidisciplinary
Gi Jung Lee, Seung Chan Hong, Jung-Gyun Lee, Jae-Hyeon Ko, Taehee Park, Young Wook Ko, Sergey Lushnikov
Summary: A new type of remote red quantum-dot (QD) component was designed and fabricated to improve the color-rendering properties of conventional white LED lightings. The red QD caps placed over white LEDs enhanced the red components in the long-wavelength range resulting in an increase of the color rendering index (CRI).
Article
Astronomy & Astrophysics
Milan S. Dimitrijevic, Magdalena D. Christova, Nenad Milovanovic, Sylvie Sahal-Brechot
Summary: Stark broadening parameters, full widths at half intensity maximum, and shifts for 34 multiplets of singly charged zinc ion were calculated using impact semiclassical perturbation formalism. The parameters due to collisions with electrons, protons, and helium ions were obtained for various electron densities and temperatures. The results were used to demonstrate the influence of Stark broadening mechanism on Zn II spectral lines in stellar atmospheres.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Optics
Xiankun Zheng, Lijin Wang, Jialin Bai, Han Zhang, Hanzhuang Zhang, Aiwei Tang, Wenyu Ji
Summary: The low device efficiency of quantum-dot light-emitting diodes (QLEDs) based on CuInZnS quantum dots is mainly attributed to trap-related recombination and is sensitive to temperature and hole-transporting layers. A higher efficiency can be achieved by using hole-transporting layers with low highest occupied molecular orbital energy levels.
LASER & PHOTONICS REVIEWS
(2023)
Article
Optics
R. B. Adamov, G. A. Melentev, I. V. Sedova, S. V. Sorokin, G. V. Klimko, I. S. Makhov, D. A. Firsov, V. A. Shalygin
Summary: This study investigates the THz luminescence in doped nanostructures with GaAs/AlGaAs quantum wells under interband optical pumping. The results show that the spatial separation of donors and acceptors can greatly enhance the integrated intensity of THz emission.
JOURNAL OF LUMINESCENCE
(2024)
Article
Optics
Yanru Li, Lei Zhong, Sha Jiang, Yutong Wang, Binyao Huang, Guotao Xiang, Li Li, Yongjie Wang, Chuan Jing, Xianju Zhou
Summary: In this study, a ratiometric luminescent thermometry based on dual-emission centers was developed using co-doped CaNb2O6 phosphors with Bi3+ and Pr3+. The obtained samples exhibited good thermosensitive and thermochromic characteristics, with a maximum absolute sensitivity of 0.09 K-1 @ 528 K and a maximum relative sensitivity of 2.17 % K-1 @ 453 K.
JOURNAL OF LUMINESCENCE
(2024)
Article
Optics
Yujing Gong, Yeqing Wang, Zhiyuan Wang, Yijian Sun, Yi Yu
Summary: Single crystals of Dy3+ single-doped and Dy3+/Tb3+ co-doped CaYAlO4 were grown and analyzed. The incorporation of Tb3+ resulted in increased absorption and emission cross sections. The fluorescence lifetimes and branching ratios of the yellow emission were affected by the presence of Tb3+. The deactivation effect of Tb3+ ions and energy transfer mechanism were also discussed.
JOURNAL OF LUMINESCENCE
(2024)
Article
Optics
Lu Chen, Zhuangzhuang Ma, Jian Chen, Wang Guo
Summary: This study focuses on enhancing the thermal robustness of phosphor converter materials by preparing composite ceramics of YAG:Ce combined with high-thermal-conductivity MgO. The composite ceramics showed high density and thermal conductivity at the optimum temperature of 1400℃. Stable laser-driven white light was obtained under blue laser excitation.
JOURNAL OF LUMINESCENCE
(2024)
Article
Optics
Yuwei Wu, Chunhui Niu, Lei Wang, Mingqing Yang, Shiyu Zhang
Summary: Er3+-doped germanate-tellurite glasses were prepared and their structure, luminescent, and temperature-sensing properties were studied. The glass exhibited large values of O2 and O6 and its luminescence intensity varied with temperature.
JOURNAL OF LUMINESCENCE
(2024)
Article
Optics
Kensei Ichiba, Takumi Kato, Kenichi Watanabe, Yuma Takebuchi, Daisuke Nakauchi, Noriaki Kawaguchi, Takayuki Yanagida
Summary: In this study, Eu-doped YVO4 single crystals with different concentrations were fabricated to evaluate their photoluminescence and scintillation properties. The results showed that the samples doped with Eu exhibited emission peaks due to 4f-4f transitions in PL and scintillation spectra. Based on the pulse height spectra, the light yield of the Eu-doped samples increased with increasing Eu concentration, while the afterglow level decreased.
JOURNAL OF LUMINESCENCE
(2024)
Article
Optics
Daiwen Xiao, Hei-Yui Kai, Anjun Huang, Menglin Song, Ka-Leung Wong, Peter A. Tanner
Summary: The emission spectra of Cs2NaEuCl6 nanoparticles synthesized by the hot injection method are explained. The dispersion of the nanoparticles in alkane solvents in the experiment allows the determination of the magnetic dipole radiative rate for the D-5(0) -F-7(1) channel in vacuum, which is in agreement with the calculated value.
JOURNAL OF LUMINESCENCE
(2024)
Article
Optics
Italia V. Barbosa, Geraldine Dantelle, Alain Ibanez, Lauro J. Q. Maia
Summary: The thermal response and luminescence properties of different oxide matrices were evaluated to design more accurate thermal probes. It was found that thermal probes emitting in BW-II provide better thermal sensing with higher signal-to-noise ratio. Additionally, doping Nd3+ in Y2O3 matrix maximizes luminescence intensity, making it a promising matrix for thermal sensing.
JOURNAL OF LUMINESCENCE
(2024)
Article
Optics
Xin Li, Yu Zhang, Hongrui Ren, Lunlong Xie, Yinsheng Di, Mengqing Han, Zhaohui Bai, Quansheng Liu, Liangliang Zhang, Jiahua Zhang
Summary: This study successfully prepared phosphor samples based on Ca3-xLuxSc2-xMgxSi3O12:Ce3+ and investigated their luminescence properties. With the increase in Lu-Mg concentration, the peak of the sample redshifted, but the thermal stability gradually decreased. The LD devices made from CLSMS:Ce3+ fluorescent materials showed a decrease in cyan-green light and an increase in red light as the Lu-Mg concentration increased.
JOURNAL OF LUMINESCENCE
(2024)
Article
Optics
Tim Pier, Julia Hopster, Thomas Juestel
Summary: This study investigates and reports on several samples of cerium-activated gallium-based garnet phosphors. The optimal activator concentration was found to be 1 atom-%. The size of non-emitting lanthanide ions and the molar concentration of cerium strongly influenced the crystal field splitting, which in turn shaped the excitation and emission wavelengths.
JOURNAL OF LUMINESCENCE
(2024)
Article
Optics
Guijie Zhao, Wei Shi, Xin Xin, Fengcai Ma, Yongqing Li
Summary: This study reveals for the first time the proton transfer pathways and changes in the photophysical properties of P-TNS with three intramolecular hydrogen bonds. The reaction mechanism and driving force for the proton transfer process are explained through analysis of potential energy surface, frontier molecular orbitals, and hydrogen bond parameters, among others.
JOURNAL OF LUMINESCENCE
(2024)
Article
Optics
Li He, Jinshu Huang, Zhengce An, Haozhang Huang, Yu Zhao, Kexin Zhong, Bo Zhou
Summary: In this study, we designed a NaYF4:Yb3+/Tm3+@NaYF4 core-shell nanostructure to achieve thermochromic upconversion and high thermal sensitivity. We found that the blue upconversion emission of Tm3+ decreased while the deep-red emission increased with elevating temperature. The sample also showed a gradual emission color change from blue to purplish-red, and the optimal relative sensitivity reached 2.79% K-1.
JOURNAL OF LUMINESCENCE
(2024)
Article
Optics
Rupesh A. Talewar
Summary: A series of Li2TiO3 phosphors doped with Mn4+ and codoped with Mn4+ and Er3+ were synthesized, which demonstrated the ability of Mn4+ ions to absorb UV-Vis photons and subsequently transfer energy to Er3+ ions, resulting in the emission of near-infrared light. These materials have the potential to enhance the absorption efficiency of Er3+-based luminescent materials.
JOURNAL OF LUMINESCENCE
(2024)
Article
Optics
Xingyuan Ma, Jianfeng Li
Summary: Carbon quantum dots (CQDs) with tunable photoluminescence properties have been synthesized using suitable carbon and dopant sources in an aqueous system. The synthesized CQDs exhibited blue, green, yellow, and red emissions, and solid-state luminescence was achieved through the preparation of solid-state fluorescent films and phosphors. This study provides important technical support for the future development of CQDs synthesis.
JOURNAL OF LUMINESCENCE
(2024)
Article
Optics
De Bin Fu, Yang Bing Xu, Yu Teng Zhang, Shan Ting Liu, Xiao Fei Yang, Sheng Hua Liu
Summary: A pair of new chiral molecules, (S)-4 and (R)-4, have been designed and synthesized by introducing valine-containing groups at symmetrical positions on the periphery of an indolo[3,2-b]carbazole unit. These molecules exhibit aggregation-induced circular dichroism (AICD) properties in DMF/water mixtures, and in a mixture with 99% water fraction, they show strong, mirror-image, blue circularly polarized luminescence (CPL) signals.
JOURNAL OF LUMINESCENCE
(2024)