Broadband near-Infrared Sensitization of Visible Upconversion Luminescence in V3+and Mo3+Co-Doped Cs2NaYCl6

2002 ◽  
Vol 106 (39) ◽  
pp. 10011-10019 ◽  
Author(s):  
Oliver S. Wenger ◽  
Hans U. Güdel
Keyword(s):  
Near Infrared ◽  
Upconversion Luminescence ◽  
Co Doped

scholarly journals Volume and surface effects on two-photonic and three-photonic processes in dry co-doped upconversion nanocrystals

Nano Research ◽  
2021 ◽  
Author(s):  
Bettina Grauel ◽  
Christian Würth ◽  
Christian Homann ◽  
Lisa Krukewitt ◽  
Elina Andresen ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Near Infrared ◽  
Surface Passivation ◽  
Upconversion Luminescence ◽  
Three Dimensional ◽  
Solid Core ◽  
Excitation Power Density ◽  
Surface Protection ◽  
Upconversion Nanocrystals ◽  
Co Doped

AbstractDespite considerable advances in synthesizing high-quality core/shell upconversion (UC) nanocrystals (NC; UCNC) and UCNC photophysics, the application of near-infrared (NIR)-excitable lanthanide-doped UCNC in the life and material sciences is still hampered by the relatively low upconversion luminescence (UCL) of UCNC of small size or thin protecting shell. To obtain deeper insights into energy transfer and surface quenching processes involving Yb3+ and Er3+ ions, we examined energy loss processes in differently sized solid core NaYF4 nanocrystals doped with either Yb3+ (YbNC; 20% Yb3+) or Er3+ (ErNC; 2% Er3+) and co-doped with Yb3+ and Er3+ (YbErNC; 20% Yb3+ and 2% Er3+) without a surface protection shell and coated with a thin and a thick NaYF4 shell in comparison to single and co-doped bulk materials. Luminescence studies at 375 nm excitation demonstrate back-energy transfer (BET) from the 4G11/2 state of Er3+ to the 2F5/2 state of Yb3+, through which the red Er3+4F9/2 state is efficiently populated. Excitation power density (P)-dependent steady state and time-resolved photoluminescence measurements at different excitation and emission wavelengths enable to separate surface-related and volume-related effects for two-photonic and three-photonic processes involved in UCL and indicate a different influence of surface passivation on the green and red Er3+ emission. The intensity and lifetime of the latter respond particularly to an increase in volume of the active UCNC core. We provide a three-dimensional random walk model to describe these effects that can be used in the future to predict the UCL behavior of UCNC.

Comprehensive investigations of near infrared downshift and upconversion luminescence mechanisms in Yb3+ single-doped and Er3+,Yb3+ co-doped SiO2 inverse opals

2017 ◽  
Vol 19 (47) ◽  
pp. 31997-32006 ◽  
Author(s):  
Zhengwen Yang ◽  
Jianzhi Yang ◽  
Jianbei Qiu ◽  
Zhiguo Song
Keyword(s):  
Near Infrared ◽  
Upconversion Luminescence ◽  
Inverse Opals ◽  
Co Doped

Comprehensive investigations of near infrared (NIR) downshift and visible upconversion luminescence (UCL) mechanisms were carried out for Yb3+ single-doped and Er3+,Yb3+ co-doped SiO2 inverse opals under excitation at 256, 378, 520 and 980 nm.

Enhanced one-band near infrared upconversion luminescence of Yb3+-Tm3+ co-doped BiOCl1-xBrx nanosheet by Tuning band gap

2021 ◽  
pp. 118295
Author(s):  
Fangyu He ◽  
Yapai Song ◽  
Qi Wang ◽  
Yongjin Li ◽  
Zhengwen Yang ◽  
...  
Keyword(s):  
Band Gap ◽  
Near Infrared ◽  
Upconversion Luminescence ◽  
Co Doped

scholarly journals Novel Polymerization of Dental Composites Using Near-Infrared-Induced Internal Upconversion Blue Luminescence

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4304
Author(s):  
Shu-Fen Chuang ◽  
Chu-Chun Liao ◽  
Jui-Che Lin ◽  
Yu-Cheng Chou ◽  
Tsung-Lin Lee ◽  
...  
Keyword(s):  
Near Infrared ◽  
Upconversion Luminescence ◽  
Blue Emission ◽  
Polymerization Reaction ◽  
Dental Composites ◽  
Resin Composites ◽  
Dental Resin ◽  
Base Composite ◽  
Different Depths ◽  
Co Doped

Blue light (BL) curing on dental resin composites results in gradient polymerization. By incorporating upconversion phosphors (UP) in resin composites, near-infrared (NIR) irradiation may activate internal blue emission and a polymerization reaction. This study was aimed to evaluate the competency of the NIR-to-BL upconversion luminance in polymerizing dental composites and to assess the appropriate UP content and curing protocol. NaYF4 (Yb3+/Tm3+ co-doped) powder exhibiting 476-nm blue emission under 980-nm NIR was adapted and ball-milled for 4–8 h to obtain different particles. The bare particles were assessed for their emission intensities, and also added into a base composite Z100 (3M EPSE) to evaluate their ability in enhancing polymerization under NIR irradiation. Experimental composites were prepared by dispensing the selected powder and Z100 at different ratios (0, 5, 10 wt% UP). These composites were irradiated under different protocols (BL, NIR, or their combinations), and the microhardness at the irradiated surface and different depths were determined. The results showed that unground UP (d50 = 1.9 μm) exhibited the highest luminescence, while the incorporation of 0.4-μm particles obtained the highest microhardness. The combined 20-s BL and 20–120-s NIR significantly increased the microhardness on the surface and internal depths compared to BL correspondents. The 5% UP effectively enhanced the microhardness under 80-s NIR irradiation but was surpassed by 10% UP with longer NIR irradiation. The combined BL-NIR curing could be an effective approach to polymerize dental composites, while the intensity of upconversion luminescence was related to specific UP particle size and content. Incorporation of 5–10% UP facilitates NIR upconversion polymerization on dental composites.

Upconversion Luminescence of MgSc2O4: Er3+/Yb3+ Nanocrystals Co-doped Alkali Ions

2020 ◽  
Vol 41 (11) ◽  
pp. 1351-1357
Author(s):  
Mei-juan YUANG ◽  
◽  
Jing LI ◽  
Hui-lian QIN ◽  
Ya-ru PENG ◽  
...  
Keyword(s):  
Upconversion Luminescence ◽  
Alkali Ions ◽  
Co Doped

Insight into the mechanism of intense NIR-to-red upconversion luminescence in Er3+ doped and Er3+–Yb3+ co-doped SrF2 nanoparticles

2021 ◽  
Vol 45 (14) ◽  
pp. 6469-6478
Author(s):  
Qingling Zeng ◽  
Wenxiang He ◽  
Fangfei Luan ◽  
Yu Yan ◽  
Hongli Du ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Theoretical Basis ◽  
Upconversion Luminescence ◽  
Insight Into ◽  
Co Doped

SrF2:Yb3+,Er3+ NPs were synthesized by the hydrothermal method and their luminescence mechanism was discussed in detail, which provided a theoretical basis for further understanding the properties of the materials.

Broadband near infrared emission of Er3+/Yb3+ co-doped fluorotellurite glass

2021 ◽  
Vol 866 ◽  
pp. 158568
Author(s):  
Jiaming Liu ◽  
Xin Huang ◽  
Heng Pan ◽  
Xu Zhang ◽  
Xiujie Fang ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Emission ◽  
Near Infrared Emission ◽  
Co Doped

scholarly journals Nano-Crystallization of Ln-Fluoride Crystals in Glass-Ceramics via Inducing of Yb3+ for Efficient Near-Infrared Upconversion Luminescence of Tm3+

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1033
Author(s):  
Jianfeng Li ◽  
Yi Long ◽  
Qichao Zhao ◽  
Shupei Zheng ◽  
Zaijin Fang ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Near Infrared ◽  
Upconversion Luminescence ◽  
Glass Ceramics ◽  
Upconversion Emission ◽  
Ceramic Composites ◽  
Wide Range ◽  
Transmission Window ◽  
Optical Applications ◽  
Upconversion Emissions

Transparent glass-ceramic composites embedded with Ln-fluoride nanocrystals are prepared in this work to enhance the upconversion luminescence of Tm3+. The crystalline phases, microstructures, and photoluminescence properties of samples are carefully investigated. KYb3F10 nanocrystals are proved to controllably precipitate in the glass-ceramics via the inducing of Yb3+ when the doping concentration varies from 0.5 to 1.5 mol%. Pure near-infrared upconversion emissions are observed and the emission intensities are enhanced in the glass-ceramics as compared to in the precursor glass due to the incorporation of Tm3+ into the KYb3F10 crystal structures via substitutions for Yb3+. Furthermore, KYb2F7 crystals are also nano-crystallized in the glass-ceramics when the Yb3+ concentration exceeds 2.0 mol%. The upconversion emission intensity of Tm3+ is further enhanced by seven times as Tm3+ enters the lattice sites of pure KYb2F7 nanocrystals. The designed glass ceramics provide efficient gain materials for optical applications in the biological transmission window. Moreover, the controllable nano-crystallization strategy induced by Yb3+ opens a new way for engineering a wide range of functional nanomaterials with effective incorporation of Ln3+ ions into fluoride crystal structures.

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