查找使用阿拉丁产品的科研文献

Impact of nitridation on the up-conversion luminescence property of Yb3Al5O12: Er3+ phosphors upon 980 nm excitation

Xiangping Li,Zhipeng Guan,Ziru Liu,Rensheng Shen,Yan Li,Runpu Zhou,Hongquan Yu,Lei Li,Baojiu Chen

In this work, the nitriding method was used to improve the up-conversion (UC) luminescence intensity and temperature sensing sensitivity of phosphor materials. Yb 3 Al 5 O 12 : Er 3+ and partially nitrided Yb 3 Al 5 O 12-1.50 x N x : Er 3+ phosphors by using AlN as nitrogen source were prepared via solid-state reaction method. The influence of nitridation on the UC luminescence and temperature sensing properties of Yb 3 Al 5 O 12 : Er 3+ phosphors upon 980 nm excitation were discussed. Almost pure red UC emission was obtained, and the intensity of the red UC emission of the samples was enhanced by 25 % after nitridation. Meanwhile, the absolute temperature sensitivity respectively derived from the intensity ratios of the green and red emissions increased by 5 % and 50 % after nitridation. Judd-Ofelt theory was utilized to analyze the change of the crystal field environment around Er 3+ and confirmed that the introduction of N 3– reduced the symmetry around Er 3+ and strengthened the covalence between Er 3+ and ligands, which may result in the enhancement of UC emission intensity and temperature sensing sensitivity. The experiment proved that Yb 3 Al 5 O 12 : Er 3+ red UC phosphors had potential application in luminescence imaging and temperature sensors.

Upconversion luminescence enhancement of β-NaYF4: Er3+/Ho3+ by introducing Ca2+ and multicolor tuning by 980 nm pulse excited

Yuzhen Sun,Huifang Bi,Tao Wang,Leilei Sun,Zexin Li,Haining Song,Fenglei Sun,Haifeng Zhou,Guangjun Zhou,Jifan Hu

NaYF 4 :10Er/0.5Ho/30Ca@NaYF 4 is designed to achieve up-conversion luminescence color adjustment under 980 nm excitation. Ho 3+ doping enhances the red emission level of the system and changes the characteristic green emission into red emission. Importantly, Ho 3+ doping increases the difference in pumping time between green and red excited states. Under short pulse-width laser excitation, the red excited state does not have enough time to be populated, which weakens the emission of red emission, and the ratio of green to red emission will change. It is an effective up-conversion luminescence enhancement method to change the symmetry of crystal field around lanthanide ions by doping Ca 2+ . The green and red emission intensities of NaYF 4 :10Er/0.5Ho/30Ca doped with 30% Ca 2+ ions are 9.0 and 6.3 times higher than those of Ca 2+ free samples, respectively.

Hydrophobic Anticancer Drug Delivery by a 980 nm Laser-Driven Photothermal Vehicle for Efficient Synergistic Therapy of Cancer Cells In Vivo

Kai Dong,Zhen Liu,Zhenhua Li,Jinsong Ren,Xiaogang Qu

Graphical A novel 980 nm laser-driven hydrophobic anticancer drug-delivery platform based on hollow CuS nanoparticles is constructed in this work. The excellent synergistic therapy combining drug treatment and photothermal ablation of cancer cells both in vitro and in vivo is demonstrated, which opens up new opportunities for biological and medical applications.

Synthesis and up-conversion luminescence of Ho3+ and Yb3+ co-doped La7P3O18 phosphors

Hao-tian ZHU,Hai-rui GUO,Qi-jing ZHENG,Chun-yan GUAN,Li-ping ZHU,Hai-bin LI,Jin-yu YANG

Ho 3+ and Yb 3+ co-doped La 7 P 3 O 18 up-conversion phosphors were prepared by a high-temperature solid-state process. XRD results reveal that the samples are mixtures of monoclinic structure La 7 P 3 O 18 crystals with P 21/ n space group and minor LaPO 4 crystals. UV—Vis DRS results indicate that La 7 P 3 O 18 crystal is an indirect semiconductor with an optical band gap of 4.10 eV. After 980 nm laser excitation, the Ho 3+ and Yb 3+ co-doped La 7 P 3 O 18 phosphors show the characteristic blue (486 nm), green (550 nm), and red (661 nm) luminescence peaks of Ho 3+ ions. The peak at 661 nm dominates in the up-conversion luminescence spectra of samples. Meanwhile, with the increase of Ho 3+ and Yb 3+ doping content, the up-conversion luminescence intensity increases first and then decreases. By increasing the doping contents of Ho 3+ and Yb 3+ up to 1 at.% and 10 at.%, respectively, concentration quenching may appear by an electric quadrupole– electric quadrupole interaction process. The pumping power dependence of luminescence indicates that the green and red emissions of samples are excited by a two-photon absorption process. The color coordinates of Ho 3+ and Yb 3+ co-doped La 7 P 3 O 18 crystals locate in the orange—red region.

Ultraviolet Upconversion Emissions of Gd3+ in β-NaLuF4:Yb3+,Tm3+,Gd3+ Nanocrystals

Song Weiye,Guo Xingyuan,He Guanghui,Qin Weiping

β-NaLuF4:20%Yb,0.5%Tm,x%Gd (x = 10,20, 30) nanocrystals were synthesized by high temperature thermal decomposition method. X-ray diffraction (XRD) show the as-prepared samples are characteristic of a pure β-NaLuF4. Transmission electron microscope (TEM) investigations indicate the nanocrystals have particle size of ∼85 nm with good monodispersity and well-defined crystallographic facets. Particularly, under 980 nm excitation, upconversion (UC) emissions in the UV range of 270–320 nm were observed in these nanocrystals, which further prove that β-NaLuF4 is an excellent host for building UV compact solid-state lasers or fiber lasers.

Tricolor Upconversion Phosphors of LiYO2:RE3+/Yb3+ (RE = Tm, Ho, Eu) for Metamerism Anti-Counterfeiting and 3D Volumetric Display

Shanshan Zhao,Dechao Yu,Benchun Li,Saima Kanwal,Tiantian Shen,Jincheng Wu,Songlin Zhuang,Dawei Zhang

The development of blue/green/red tricolor upconversion (UC) phosphors under invisible light irradiation has attracted significant interest in emerging applications such as anti-counterfeiting, three-dimensional (3D) optical data storage, and solid-state 3D displays. In this study, a series of LiYO 2 :RE 3+ ,Yb 3+ (RE = Tm, Ho, Eu) phosphors are successfully prepared via first precipitation process followed by calcination, and completely optimized for efficient tricolor UC luminescence with 980 nm laser excitation. Mechanisms involving two- or three-photon absorption processes and low-phonon-energy-suppressed multi-phonon relaxation have been proposed for Ho 3+ (Eu 3+ )/Yb 3+ and Tm 3+ /Yb 3+ codoping, respectively. In addition, the RE 3+ (Yb 3+ ) concentration-induced phase transition of the LiYO 2 host is discussed for interesting possibilities in spectral regulation. Based on the broad color gamut achieved by the tricolor UC phosphor mixture, homochromatic and polychromatic metamerisms are experimentally fabricated via screen printing for high-level anti-counterfeiting and information security. Moreover, for a proof-of-concept demonstration, prototypes of 3D optical data storage and volumetric displays are constructed by embedding tricolor UC mixtures and their 3D printed patterns in polydimethylsiloxane. It is believed that the continuous exploration of tricolor UC under invisible light excitation for metamerism anti-counterfeiting and 3D displays can promote the development of high-level information security and advanced volumetric display technologies.

Mechanisms of Upconversion Luminescence of Er3+-Doped NaYF4 via 980 and 1530 nm Excitation

Yu Liu,Ziwen Zhou,Shaojian Zhang,Enming Zhao,Jing Ren,Lu Liu,Jianzhong Zhang

To date, the mechanisms of Er3+upconversion luminescence via 980 and 1530 nm excitation have been extensively investigated; however, based on discussions, they either suffer from the lack of convincing evidence or require elaborated and time-consuming numerical simulations. In this work, the steady-state and time-resolved upconversion luminescence data of Er3+-doped NaYF4were measured; we therefore investigated the upconversion mechanisms of Er3+on the basis of the spectroscopic observations and the simplified rate equation modeling. This work provides a relatively simple strategy to reveal the UCL mechanisms of Er3+upon excitation with various wavelengths, which may also be used in other lanthanide ion-doped systems.

Enhanced upconversion luminescence and tuned red-to-green emission ratio of LiGdF4 nanocrystals via Ca2+ doping

Zhenmin Xiong,Yushi Yang,Youfa Wang

LiGdF4 nanoparticles (NPs) with different Ca2+ contents were synthesized by a thermal decomposition method. The as-prepared NPs were able to emit green and strong red light when excited by a 980 nm laser through a two-photon process and they were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectroscopy. Rietveld refinement was performed to explore the structure and phase composition of the product. It was found that Ca2+ ions were vital to the successful synthesis of LiGdF4 NPs and an appropriate Ca2+ content (ca. 19%) yielded the product with highest purity. The purity of the obtained product was highly correlated with the PL intensity and red/green light intensity ratio.

Enhanced downconversion luminescence of NaLuF4:Yb3+,Er3+ micrometer hexagonal prismatic crystals under 980 nm excitation

Shaohua Wu,Yu Yang,Shuang Wu,Yanhui Dong,Hao Cui,Daguang Li,Weiping Qin

NaLuF 4 :Yb 3+ ,Er 3+ micrometer prismatic crystals are potential materials for the preparation of optical waveguide devices. However, structural defects and OH – groups are generated inside and on their surfaces during growth processes. The structural defects and OH – groups lead to a large depletion of excitation energy and severely quench the downconversion luminescence of Er 3+ . In addition, the Yb 3+ /Er 3+ co-doping ratio significantly affects the downconversion luminescence of the microcrystals, which in turn affects the performance of the optical waveguide amplifiers based on the microcrystals. By adjusting the co-doping ratio of Yb 3+ and Er 3+ in the microcrystals and removing the defects in the crystals, their downconversion luminescence performance was significantly improved. The results showed that the downconversion luminescence under the excitation from a 980 nm laser reached the maximum value when the doping ratio of Yb 3+ and Er 3+ was 20:1.5. In addition, the OH – groups and structural defects in the micrometer crystals were significantly eliminated by ion-exchange and high-temperature annealing treatments, and the crystalline quality was significantly improved. After ion-exchange and high-temperature annealing treatments, the downconversion luminescence enhancement of NaLuF 4 :Yb 3+ ,Er 3+ microcrystals was 2.5 times that of the untreated samples.

Preparation and up-conversion luminescence characteristics studies of K3YF6: Ho3+, Yb3+ with cryolite structure

Pengfei Shuai,Libing Liao,Qingfeng Guo,Dan Yang,Ruiqi Shi,Lefu Mei

Cryolite was considered to be an ideal up-conversion host material due to its low phonon energy, which can effectively suppress the radiation-free transition process of excited state energy levels. In the present paper, a novel up-conversion material K 3 YF 6 :Ho 3+ , Yb 3+ with cryolite structure was prepared successfully using a high-temperature solid state method. The up-conversion luminescence properties of K 3 YF 6 doped with different Ho 3+ /Yb 3+ doping ratio were investigated and the optimal doping ratio were confirmed in this system. Under 980 nm excitation, Ho 3+ /Yb 3+ co-doped K 3 YF 6 revealed a strong green emission at the 541 nm, 549 nm and a weak red emission peaking at 666 nm, corresponding to the 5 F 4 , 5 S 2 → 5 I 8 and 5 F 5 → 5 I 8 transitions of Ho 3+ , respectively. All the red and green up-conversion emission of K 3 YF 6 :Ho 3+ , Yb 3+ belong to two-photon process and energy transfer from Yb 3+ to Ho 3+ simultaneously. Additionally, to understand the energy transfer and electronic transition process of the red and green light emitted, the possible luminescence mechanism were also analyzed in this paper. All the results indicate that Ho 3+ /Yb 3+ co-doped K 3 YF 6 have potential application value in green up-conversion luminescent materials.

Growth and luminescence characteristics of LiYF4: Yb,Er nanoparticles

Shuang Wu,Yanhui Dong,Hao Cui,Daguang Li,Weiping Qin

The morphology and size of LiYF 4 :Yb,Er nanoparticles were controlled using an automatic nanomaterial synthesizer by changing the reaction time at high temperature. It was found that the nanoparticles underwent a growth and change process from small to large and then to small, and then remained at a basically stable size, reflecting the different growth stages of the nanoparticles, such as nucleation, growth, phase transition, and internal Ostwald ripening, etc. XRD analyses showed that LiF nanocrystals were first formed during the reaction process, and then all the products were converted into LiYF 4 nanocrystals. Under the excitation of a 980 nm laser, the LiYF 4 :Yb,Er nanoparticles showed regular downconversion and upconversion luminescence properties, which was basically consistent with the regularity of nanocrystal growth. The experimental results showed that the upconversion luminescence and downconversion luminescence intensities of nanocrystals increasd rapidly when the synthesis time was between 0 and 50 min, and they increased slowly after the synthesis time exceeded 50 min.

980 nm Near-Infrared Light-Emitting Diode Using All-Inorganic Perovskite Nanocrystals Doped with Ytterbium Ions

Zhenglan Ye,Taoran Liu,Dan Chen,Yazhou Yang,Jiayi Li,Yaqing Pang,Xiangquan Liu,Yuhua Zuo,Jun Zheng,Zhi Liu,Buwen Cheng