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.

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.

Preparation and Upconversion Luminescence Properties of Tb3+-Yb3+ Co-Doped Phosphate Inverse Opals

2011 ◽  
Vol 311-313 ◽  
pp. 1227-1231
Author(s):  
Kan Zhu ◽  
Zheng Wen Yang ◽  
Dong Yan ◽  
Zhi Guo Song ◽  
Da Cheng Zhou ◽  
...  
Keyword(s):  
Band Gap ◽  
Self Assembly ◽  
Photonic Band Gap ◽  
Upconversion Luminescence ◽  
Sol Gel ◽  
Inverse Opals ◽  
Assembly Technique ◽  
Photonic Band Gap Materials ◽  
Photonic Band ◽  
Co Doped

Upconversion (UC) luminescence photonic band gap materials Tb3+-Yb3+ co-doped phosphate inverse opal photonic crystals were prepared by a self-assembly technique in combination with a sol-gel method. The effect of photonic band gap on UC luminescence was investigated in inverse opals. Effective suppression of the UC luminescence was inspected if the photonic band gap overlapped with the emission band of Tb3+ ions.

UPCONVERSION LUMINESCENCE ENHANCEMENT OF NaYF4:Yb3+, Er3+ NANOPARTICLES ON INVERSE OPAL SURFACE

2014 ◽  
Vol 21 (01) ◽  
pp. 1450017 ◽  
Author(s):  
JIAYAN LIAO ◽  
ZHENGWEN YANG ◽  
HANGJUN WU ◽  
SHENFENG LAI ◽  
JIANBEI QIU ◽  
...  
Keyword(s):  
Upconversion Luminescence ◽  
Upconversion Emission ◽  
Band Gaps ◽  
Inverse Opal ◽  
Photonic Band Gaps ◽  
Selective Reflection ◽  
Inverse Opals ◽  
Upconversion Emissions ◽  
Photonic Band ◽  
Co Doped

LaPO 4 inverse opal photonic crystals with different photonic band gaps were fabricated by template-assisted method. The Yb 3+/ Er 3+ co-doped NaYF 4 nanoparticles were deposited on the surfaces of the inverse opals, and their up-conversion emission properties were investigated. The upconversion emissions of Yb 3+/ Er 3+ co-doped NaYF 4 nanoparticles on the inverse opal surfaces have been enhanced when the upconversion emission bands of the nanoparticles are in the range of photonic band gaps of the inverse opals, which is attributed to an efficient and selective reflection of photonic band gaps.

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 modification induced near infrared luminescence enhancement of Bi2Ti2O7:Yb3+, Er3+ inverse opals

2019 ◽  
Vol 208 ◽  
pp. 150-154 ◽  
Author(s):  
Youtao Ren ◽  
Zhengwen Yang ◽  
Mingjun Li ◽  
Jianbei Qiu ◽  
Zhiguo Song ◽  
...  
Keyword(s):  
Near Infrared ◽  
Upconversion Luminescence ◽  
Luminescence Enhancement ◽  
Inverse Opals ◽  
Infrared Luminescence

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
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