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.

scholarly journals Multiband emission from single β-NaYF4(Yb,Er) nanoparticles at high excitation power densities and comparison to ensemble studies

Nano Research ◽  
2021 ◽  
Author(s):  
Florian Frenzel ◽  
Christian Würth ◽  
Oleksii Dukhno ◽  
Frédéric Przybilla ◽  
Lisa M. Wiesholler ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Single Particle ◽  
Near Infrared ◽  
Upconversion Luminescence ◽  
Excited State Absorption ◽  
High Energy ◽  
Excitation Power ◽  
Relaxation Processes ◽  
Excitation Power Density ◽  
Radiative Relaxation

AbstractEnsemble and single particle studies of the excitation power density (P)-dependent upconversion luminescence (UCL) of core and core-shell β-NaYF4:Yb,Er upconversion nanoparticles (UCNPs) doped with 20% Yb3+ and 1% or 3% Er3+ performed over a P regime of 6 orders of magnitude reveal an increasing contribution of the emission from high energy Er3+ levels at P > 1 kW/cm2. This changes the overall emission color from initially green over yellow to white. While initially the green and with increasing P the red emission dominate in ensemble measurements at P < 1 kW/cm2, the increasing population of higher Er3+ energy levels by multiphotonic processes at higher P in single particle studies results in a multitude of emission bands in the ultraviolet/visible/near infrared (UV/vis/NIR) accompanied by a decreased contribution of the red luminescence. Based upon a thorough analysis of the P-dependence of UCL, the emission bands activated at high P were grouped and assigned to 2–3, 3–4, and 4 photonic processes involving energy transfer (ET), excited-state absorption (ESA), cross-relaxation (CR), back energy transfer (BET), and non-radiative relaxation processes (nRP). This underlines the P-tunability of UCNP brightness and color and highlights the potential of P-dependent measurements for mechanistic studies required to manifest the population pathways of the different Er3+ levels.

scholarly journals Upconversion Luminescence of Silica–Calcia Nanoparticles Co-doped with Tm3+ and Yb3+ Ions

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 937
Author(s):  
Katarzyna Halubek-Gluchowska ◽  
Damian Szymański ◽  
Thi Ngoc Lam Tran ◽  
Maurizio Ferrari ◽  
Anna Lukowiak
Keyword(s):  
Energy Transfer ◽  
Near Infrared ◽  
Upconversion Luminescence ◽  
Sol Gel ◽  
Emission Spectra ◽  
Transmission Electron ◽  
Characteristic Emission ◽  
Diffraction Patterns ◽  
Size Of Particles ◽  
Average Size

Looking for upconverting biocompatible nanoparticles, we have prepared by the sol–gel method, silica–calcia glass nanopowders doped with different concentration of Tm3+ and Yb3+ ions (Tm3+ from 0.15 mol% up to 0.5 mol% and Yb3+ from 1 mol% up to 4 mol%) and characterized their structure, morphology, and optical properties. X-ray diffraction patterns indicated an amorphous phase of the silica-based glass with partial crystallization of samples with a higher content of lanthanides ions. Transmission electron microscopy images showed that the average size of particles decreased with increasing lanthanides content. The upconversion (UC) emission spectra and fluorescence lifetimes were registered under near infrared excitation (980 nm) at room temperature to study the energy transfer between Yb3+ and Tm3+ at various active ions concentrations. Characteristic emission bands of Tm3+ ions in the range of 350 nm to 850 nm were observed. To understand the mechanism of Yb3+–Tm3+ UC energy transfer in the SiO2–CaO powders, the kinetics of luminescence decays were studied.

Near infrared fluorescence and energy transfer in Ce/Nd Co-doped CaxSr1−xS

2011 ◽  
Vol 131 (1) ◽  
pp. 134-137 ◽  
Author(s):  
Jian-Xin Meng ◽  
Wen-Jiao Wan ◽  
Li-Li Fan ◽  
Chuang-Tao Yang ◽  
Qing-Qing Chen ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Near Infrared ◽  
Near Infrared Fluorescence ◽  
Co Doped

Upconversion luminescence, optical thermometric properties and energy transfer in Yb3+/Tm3+ co-doped phosphate glass

2018 ◽  
Vol 81 ◽  
pp. 78-83 ◽  
Author(s):  
Yong Chen ◽  
Guohua Chen ◽  
Xiangyu Liu ◽  
Jiwen Xu ◽  
Xiujuan Zhou ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Phosphate Glass ◽  
Upconversion Luminescence ◽  
Co Doped

Energy transfer and upconversion luminescence in Tm3+/Yb3+ co-doped lanthanum–zinc–lead–tellurite glasses

2008 ◽  
Vol 128 (1) ◽  
pp. 135-141 ◽  
Author(s):  
Qiuhua Nie ◽  
Xujie Li ◽  
Shixun Dai ◽  
Tiefeng Xu ◽  
Zhe Jin ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Upconversion Luminescence ◽  
Tellurite Glasses ◽  
Co Doped

Greatly enhanced broadband near-infrared emission due to energy transfer from Cr3+ to Ni2+ in transparent magnesium aluminosilicate glass ceramics

2009 ◽  
Vol 24 (2) ◽  
pp. 310-315 ◽  
Author(s):  
Jin Luo ◽  
Shifeng Zhou ◽  
Botao Wu ◽  
Hucheng Yang ◽  
Song Ye ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Near Infrared ◽  
Glass Ceramics ◽  
Infrared Emission ◽  
Aluminosilicate Glass ◽  
Nanocrystalline Phase ◽  
Doped Glass ◽  
Near Infrared Emission ◽  
532 Nm ◽  
Co Doped

Cr3+/Ni2+ co-doped optically transparent magnesium aluminosilicate glass-ceramics containing MgAl2O4 nanocrystals have been prepared by heat-treatment. Greatly enhanced broadband near-infrared emission centered at 1216 nm in Cr3+/Ni2+ co-doped glass ceramics is observed when compared with the Ni2+ single-doped glass ceramics under 532 nm excitation. The observed enhancement of infrared emission is attributed to the energy transfer from Cr3+ to Ni2+ ions in the nanocrystalline phase, which leads to the emission due to 3T2(3F) → 3A2(3F) transition of octahedral Ni2+ ions.

scholarly journals Up-conversion luminescence in low phonon heavy metal oxide glass co-doped with Er3+/Ho3+

2018 ◽  
Vol 10 (1) ◽  
pp. 2 ◽  
Author(s):  
T. Ragiń ◽  
A. Baranowska ◽  
M. Sołtys ◽  
A. Górny ◽  
J. Zmojda ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Energy Transfer ◽  
Metal Oxide ◽  
Upconversion Luminescence ◽  
Bismuth Germanate ◽  
Oxide Glass ◽  
Oxide Glasses ◽  
Mid Infrared ◽  
Co Doped ◽  
Germanate Glasses

In this paper, heavy metal oxide glasses co-doped with erbium and holmium ions have been synthesized. Glass composition, based on the bismuth and germanium oxides, has been selected in terms of high thermal stability (delta T = 125 °C), high refractive index (n = 2.19) and low maximum phonon energy (hvmax = 724 cm-1). Up-conversion luminescence spectra under the 980 nm laser diode excitation have been observed as a result of radiative transitions within the quantum energy level structures of Er3+ and Ho3+ ions. Optimization of rare earth ions content has been conducted, the highest emission intensity in the visible wavelength range has been observed in glass co-doped with molar concentration 0.5 Er2O3 / 0.5 Ho2O3. Full Text: PDF ReferencesF. Zhang, Z. Bi, A. Huang, Z. Xiao, "Visible luminescence properties of Er3+?Pr3+ codoped fluorotellurite glasses", Opt. Materials 41, 112 (2014). CrossRef S. Li, S. Ye, T. Liu, H. Wang, D. Wang, "Enhanced up-conversion emissions in ZnO-LiYbO2:RE3+ (RE = Er or Ho) hybrid phosphors through surface modification", J. All. Comp. 658, 85 (2016). CrossRef J. Fu, X. Zhang, Z. Chao, Z. Li, J. Liao, D. Hou, H. Wen, X. Lu, X. Xie, "Enhanced upconversion luminescence of NaYF4:Yb, Er microprisms via La3+ doping", Opt. Laser Tech. 88, 280 (2017). CrossRef Y. Tian, R. Xu, L. Hu, J. Zhang, "2.7 ?m fluorescence radiative dynamics and energy transfer between Er3+ and Tm3+ ions in fluoride glass under 800 nm and 980 nm excitation", J. Quant. Spec. Rad. Tra. 113, 87 (2012). CrossRef M. Zhang, A. Yang, Y. Peng, B. Zhang, H. Ren, W. Guo, Y. Yang, C. Zhai, Y. Wang, Z. Yang, D. Tang, "Dy3+-doped Ga?Sb?S chalcogenide glasses for mid-infrared lasers", Mat. Res. Bul. 70, 55 (2015). CrossRef G. Yang, T. Li, "Broadband 1.53 ?m emission in Er3+-doped Ga-Bi-Pb-Ge heavy metal oxide glasses", J. Rare Earths 26, 924 (2008). CrossRef Y. Guo, Y. Tian, L. Zhang, L. Hu, J. Zhang, "Erbium doped heavy metal oxide glasses for mid-infrared laser materials", J. Non-Cryst. Solids 377, 119 (2013). CrossRef Z. Hou, Z. Xue, F. Li, M. Wang, X. Hu, S. Wang, "Luminescence and up-conversion mechanism of Er3+/Ho3+ co-doped oxyfluoride tellurite glasses and glass?ceramics", J. All. Comp. 577, 523 (2013). CrossRef X. Li, Q. Nie, S. Dai, T. Xu, L. Lu, X. Zhang, "Energy transfer and frequency upconversion in Ho3+/Yb3+ co-doped bismuth-germanate glasses", J. All. Comp. 454, 510 (2008). CrossRef S.S. Rojas, J.E. De Souza, M.R.B. Andreeta, A.C. Hernandes, "Influence of ceria addition on thermal properties and local structure of bismuth germanate glasses", J. Non-Cryst. Solids 356, 2942 (2010). CrossRef M.S. Ebrahim, Irina, Mid-infrared coherent sources and applications, Springer (2008). CrossRef T. Ragin, J. Zmojda, M. Kochanowicz, P. Miluski, P. Jelen, M. Sitarz, D. Dorosz, "Enhanced mid-infrared 2.7 ?m luminescence in low hydroxide bismuth-germanate glass and optical fiber co-doped with Er3 +/Yb3 + ions", J. Non-Cryst. Solids 457, 169 (2017). CrossRef K. Biswas, A.D. Sontakke, R. Sen, K. Annapurna, "Enhanced 2 ?m broad-band emission and NIR to visible frequency up-conversion from Ho3+/Yb3+ co-doped Bi2O3?GeO2?ZnO glasses", Spectr. Acta. Part A, Mol. Biomol. Spectr. 112, 301-308 (2013). CrossRef R.S. Romaniuk, D. Dorosz, J. Żmojda, M. Kochanowicz, W. Mazerski, "Upconversion luminescence in tellurite glass codoped with Yb3+/Ho3+ ions", Proc. of SPIE 8903, 890307 (2013). CrossRef

Self-assembled three-dimensional architectures of VO2:Yb3+,Er3+ controlled synthesis and dual-power dependent luminescence properties

2018 ◽  
Vol 42 (18) ◽  
pp. 15436-15443 ◽  
Author(s):  
Wei Zheng ◽  
Rui Wang ◽  
Yuemei Li ◽  
Yanling Xu ◽  
Baoyu Su
Keyword(s):  
Energy Transfer ◽  
Three Dimensional ◽  
Luminescence Properties ◽  
Controlled Synthesis ◽  
Higher Power ◽  
Self Assembled ◽  
Co Doped ◽  
Dual Power

The higher power-sensitization triggers welding of the structure, favoring energy transfer between nanoparticles in Er3+/Yb3+ co-doped VO2.

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