808-nm-light-excited high sensitivity ratiometric NIR nanothermometer via phonon assisted positive and negative thermal quenching effect

2022 ◽  
pp. 127935
Author(s):  
Yubin Wang ◽  
Lei Lei ◽  
Enyang Liu ◽  
Zhanling Lu ◽  
Shiqing Xu
Keyword(s):  
Thermal Quenching ◽  
High Sensitivity ◽  
Quenching Effect

scholarly journals Ratiometric Fluorescent Biosensors for Glucose and Lactate Using an Oxygen-Sensing Membrane

Biosensors ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 208
Author(s):  
Hong Dinh Duong ◽  
Jong Il Rhee
Keyword(s):  
Limit Of Detection ◽  
Oxygen Sensing ◽  
High Sensitivity ◽  
Glucose Sensing ◽  
Oxidation Reactions ◽  
Lactate Oxidase ◽  
Lactate Oxidation ◽  
Detection Range ◽  
Quenching Effect ◽  
Sensing Membrane

In this study, ratiometric fluorescent glucose and lactate biosensors were developed using a ratiometric fluorescent oxygen-sensing membrane immobilized with glucose oxidase (GOD) or lactate oxidase (LOX). Herein, the ratiometric fluorescent oxygen-sensing membrane was fabricated with the ratio of two emission wavelengths of platinum meso-tetra (pentafluorophenyl) porphyrin (PtP) doped in polystyrene particles and coumarin 6 (C6) captured into silica particles. The operation mechanism of the sensing membranes was based on (i) the fluorescence quenching effect of the PtP dye by oxygen molecules, and (ii) the consumption of oxygen levels in the glucose or lactate oxidation reactions under the catalysis of GOD or LOX. The ratiometric fluorescent glucose-sensing membrane showed high sensitivity to glucose in the range of 0.1–2 mM, with a limit of detection (LOD) of 0.031 mM, whereas the ratiometric fluorescent lactate-sensing membrane showed the linear detection range of 0.1–0.8 mM, with an LOD of 0.06 mM. These sensing membranes also showed good selectivity, fast reversibility, and stability over long-term use. They were applied to detect glucose and lactate in artificial human serum, and they provided reliable measurement results.

Nanocrystalline Phosphors for Lighting and Detection Applications

2010 ◽  
Vol 654-656 ◽  
pp. 1130-1133 ◽  
Author(s):  
Christopher J. Summers ◽  
Hisham M. Menkara ◽  
Richard A. Gilstrap ◽  
Mazen Menkara ◽  
Thomas Morris
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Shell Growth ◽  
Stokes Shift ◽  
Thermal Quenching ◽  
High Sensitivity ◽  
In Situ Monitoring ◽  
White Leds ◽  
Sensing Applications ◽  
Improved Stability

We report the development of new nanoparticle phosphors and quantum dot structures designed for applications to enhance the color rendering and efficiency of high brightness white LEDs, as well as for bio-sensing applications. The intrinsic problem of self-absorption, high toxicity, and high sensitivity to thermal quenching of conventional quantum dot systems has prevented their adoption to LED devices. Doped Cd-free quantum dots may circumvent these issues due to their distinct Stokes shift and improved stability at high temperature. We report on the modification of Mn-doped ZnSe/ZnS core-shell quantum dots for application to the (blue diode + yellow emitter) white LED system. Band gap tuning for 460 nm excitation, inorganic shell growth and in-situ monitoring for enhanced efficiency, and analysis of thermal stability will are reported.

Thermoluminescence study on TlGaSSe layered single crystals

2014 ◽  
Vol 28 (16) ◽  
pp. 1450133 ◽  
Author(s):  
Serdar Delice ◽  
Nizami M. Gasanly
Keyword(s):  
Single Crystals ◽  
Heating Rate ◽  
Thermal Quenching ◽  
Activation Energies ◽  
Temperature Peak ◽  
Heating Rates ◽  
Quenching Effect ◽  
Defect Centers ◽  
General Order ◽  
Maximum Temperatures

The defect centers in TlGaSSe single crystals have been investigated by performing thermoluminescence (TL) measurements with various heating rates between 0.5 K/s and 1.0 K/s in the temperature range of 10–180 K. The TL spectra, with peak maximum temperatures at 39 K and 131 K, revealed the existences of two defect levels. Curve fitting, initial rise and peak shape methods were used to determine the activation energies of two defect centers. The experimental results also showed that the trapping process was dominated by second-order kinetics for the trap related with low temperature peak while the general order (mixed order) kinetics was dominant for the trap donated to high temperature peak. Furthermore, heating rate dependences and traps distributions were studied for two defect centers separately. Thermal quenching effect dominates the behavior of these defects as the heating rate is increased. Also, quasi-continuous distributions were established with the increase of the activation energies from 16 meV to 27 meV and from 97 meV to 146 meV for the traps associated with the peaks observed at low and high temperatures, respectively.

scholarly journals Photoluminescent Properties of Hydrogenated Amorphous Silicon Oxide Powders

2002 ◽  
Vol 17 (5) ◽  
pp. 977-980 ◽  
Author(s):  
Wei-Fang Su ◽  
Hong-Ru Guo
Keyword(s):  
Amorphous Silicon ◽  
Silicon Oxide ◽  
Hydrogenated Amorphous Silicon ◽  
Thermal Quenching ◽  
Amorphous Semiconductors ◽  
Electronic Density ◽  
Quenching Effect ◽  
Oxide Powders ◽  
Amorphous Silicon Oxide ◽  
Hydrogenated Amorphous

The photoluminescence properties of hydrogenated amorphous silicon oxide powder SiO0.92H0.53 were investigated. The powder was prepared by reacting lithium with trichlorosilane in tetrahydrofuran. The luminescence peak energy was located between 1.0 and 1.61 eV. The samples were treated under different conditions such as annealing, hydrolysis, and hydrolysis plus HF etching. The changes of the photoluminescent intensity and location on the treated powders can be explained by the electronic density of state model of amorphous semiconductors. The temperature dependence of luminescence properties of the powders can be described by the relationship of thermal quenching effect: ln[Io/I(T) – 1] = ED/Eo = T/To at temperatures between 100 and 300 K.

scholarly journals (Ce, Gd):YAG-Al2O3 composite ceramics for high-brightness yellow light-emitting diode applications

2021 ◽  
Author(s):  
Xiaoyun Li ◽  
Jian Chen ◽  
Zhuguang Liu ◽  
Zhonghua Deng ◽  
Qiufeng Huang ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Thermal Quenching ◽  
Second Phase ◽  
Composite Ceramics ◽  
Vacuum Sintering ◽  
Phosphor Material ◽  
High Brightness ◽  
Light Emitting ◽  
Quenching Effect ◽  
Noticeable Improvement

Abstract Gd3+ ions were doped in Ce:YAG ceramics as the phosphor material for the high-brightness yellow LED (565-590 nm). Besides the role of spectral modulation, the introduction of Gd3+ ions also exacerbates the thermal quenching effect. To increase its thermal performance, Al2O3 were introduced as the second phase and (Ce0.6%Y69.4%Gd30%)3Al5O12-z% Al2O3 (z=0, 10, 20, 30, 40) composite ceramics were fabricated by vacuum sintering. Their composite microstructures and phase structures were characterized. As the amount of Al2O3 increases from 0 wt% to 40 wt%, there is a noticeable improvement on the thermal conductivity. The thermal stability also increases and the operating temperature of ceramics reduced from 141.1 °C to 132.2 °C. Collaborating composite ceramics with InGaN blue chips, the steady-state luminous efficiency of 40 wt%-Al2O3 yellow LED reaches the highest value of 109.49 lm/W, which is 8.54 % higher than that of Al2O3-free sample. Additionally, scattering behavior and conversion efficiency of composite ceramics with different thicknesses were investigated.

Highly Fluorescent N-Doped Carbon Quantum Dots Derived from Bamboo Stems for Selective Detection of Fe3+ Ions in Biological Systems

2021 ◽  
Vol 17 (2) ◽  
pp. 312-321
Author(s):  
Jiamin Yan ◽  
Yuneng Lu ◽  
Shaowen Xie ◽  
Haihu Tan ◽  
Weilan Tan ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Biological Systems ◽  
High Sensitivity ◽  
Carbon Quantum Dots ◽  
Clinical Diagnostics ◽  
Quenching Effect ◽  
Biologically Relevant ◽  
Sensing Platform ◽  
Wide Ph Range ◽  
High Fluorescence

The establishment of sensing platform for trace analysis of Fe3+ in biological systems is meaningful for health monitoring. Herein, a Fe3+ sensitive fluorescent nanoprobe was constructed based on highly fluorescent N-doped carbon quantum dots (NCQDs) derived from bamboo stems through a hydrothermal method employing ethylenediamine as the nitrogen dopant. The prepared NCQDs had a uniformly distributed size and their mean size was around 2.43 nm. Abundant functional groups (C=N, N-H, C=O, and carboxyl) anchored on NCQDs demonstrated successful doping of N in CQDs. The obtained NCQDs possessed a high fluorescence quantum yield of 20.02% and outstanding fluorescence stability over a wide pH range and at high ionic strengths. Moreover, Fe3+ ions presented a specific fluorescent quenching effect to the as-prepared NCQDs. The calibration curve for fluorescence quenching degree corresponding to Fe3+ concentration showed a linear response in a range of 0.01–10 µM, and detection limit was 0.486 µM, which indicated that the NCQDs had high sensitivity to Fe3+ ions. Ascribed to these unique properties, the NCQDs were selected as luminescent probes for trace amount of Fe3+ ions in human serum. These results demonstrated their promising use in clinical diagnostics and other biologically relevant studies.

Inverse thermal quenching effect in lanthanide-doped upconversion nanocrystals for anti-counterfeiting

2018 ◽  
Vol 6 (20) ◽  
pp. 5427-5433 ◽  
Author(s):  
Lei Lei ◽  
Daqin Chen ◽  
Can Li ◽  
Feng Huang ◽  
Junjie Zhang ◽  
...  
Keyword(s):  
Energy Level ◽  
Thermal Quenching ◽  
Defect State ◽  
Quenching Effect ◽  
High Security ◽  
Upconversion Nanocrystals

An inverse thermal quenching effect is actualized in uniform lanthanide-doped Na3ZrF7 by artificially introducing defect state with an appropriate energy level. These kinds of systems are very suitable for anti-counterfeiting with high security.

Enhancing negative thermal quenching effect via low-valence doping in two-dimensional confined core–shell upconversion nanocrystals

2018 ◽  
Vol 6 (43) ◽  
pp. 11587-11592 ◽  
Author(s):  
Lei Lei ◽  
Jienan Xia ◽  
Yao Cheng ◽  
Yuansheng Wang ◽  
Gongxun Bai ◽  
...  
Keyword(s):  
Emission Intensity ◽  
Thermal Quenching ◽  
Core Shell ◽  
Two Dimensional ◽  
Quenching Effect ◽  
Upconversion Nanocrystals

Doping low-valence ions in core–shell NC is applied to improve negative thermal quenching effect. With the increase in temperature from 293 to 413 K, the UC emission intensity of 20Yb/2Er : NaGdF4 (12 nm) increases by 2.2 times, whereas that of NaGdF4@20Ca/20Yb/2Er: NaGdF4 (11 nm) increases by 10.9 times.

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