scholarly journals Cation Crosslinking-Induced Stable Copper Nanoclusters Powder as Latent Fingerprints Marker

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3371
Author(s):  
Yi Qiu ◽  
Zhuoqi Wen ◽  
Shiliang Mei ◽  
Jinxin Wei ◽  
Yuanyuan Chen ◽  
...  
Keyword(s):  
Precipitation Method ◽  
Light Sources ◽  
Latent Fingerprints ◽  
Copper Nanoclusters ◽  
Compact Structure ◽  
Light Emitting Devices ◽  
Physical Form ◽  
Display Technology ◽  
The Stability ◽  
Capping Ligands

Luminescent copper nanoclusters (Cu NCs) have shown great potential in light-emitting devices (LEDs), chemical sensing, catalysis and biological fields. However, their practical use has been restricted by poor stability, and study on the stability of Cu NCs solid powder along with the mechanism is absent. In this study, stablized Cu NCs powder was first obtained by cation crosslinking method. Compared with the powder synthesized by solvent precipitation method, the stability of Cu NCs powder crosslinked by ionic inducer Ce3+ was enhanced around 100-fold. The storage time when the fluorescence intensity decreased to 85% (T85) was improved from 2 h to 216 h, which is the longest so far. The results of characterizations indicated that the aggregation structure was formed by the binding of Ce3+ with the capping ligands of Cu NCs, which helped in obtaining Ce-Cu NCs powder from aggregate precipitation in solution. Furthermore, this compact structure could avoid the destruction of ambient moisture resulting in long-lasting fluorescence and almost unchanged physical form. This demonstrated that phosphor, with excellent characteristics of unsophisticated synthesis, easy preservation and stable fluorescence, showed great potential in light sources, display technology and especially in latent fingerprints visualization on different substrates for forensic science.

Novel ultrabright luminescent copper nanoclusters and application in light-emitting devices

2021 ◽  
Vol 57 (77) ◽  
pp. 9890-9893
Author(s):  
Qiu-Qin Huang ◽  
Mei-Yue Hu ◽  
Yan-Li Li ◽  
Nan-Nan Chen ◽  
Yi Li ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Single Component ◽  
Copper Nanoclusters ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Phosphorescence Emission ◽  
White Light Emitting Diodes

Ultra-small tri/tetra-nuclear copper nanoclusters (Cu3/Cu4) exhibit ultrabright phosphorescence emission (Фem = 71.8 and 63.5%). Cu3 is firstly applied as a single component phosphor for white light-emitting diodes with favourable characteristics.

scholarly journals Crystallographic, Energy Gap, Photoluminescence and Photo-Catalytic Investigation of Cu Doped Cd0.9Zn0.1S Nanostructures by Co-Precipitation Method

2021 ◽  
Author(s):  
P. Raju ◽  
Joseph Prince Jesuraj ◽  
S. Muthukumaran
Keyword(s):  
Crystallite Size ◽  
Energy Gap ◽  
Wavelength Region ◽  
Lattice Parameter ◽  
Precipitation Method ◽  
Optical Absorbance ◽  
Stability Measurement ◽  
Cubic Structure ◽  
The Stability ◽  
Co Precipitation

Abstract The controlled synthesis of Cd0.9Zn0.1S, Cd0.89Zn0.1Cu0.01S and Cd0.87Zn0.1Cu0.03S nanostructures by simple chemical co-precipitation technique was reported. The XRD investigation confirmed the basic CdS cubic structure on Zn-doped CdS and also Zn, Cu dual doped CdS with no secondary/impurity related phases. No modification in cubic structure was detected during the addition of Zn/Cu into CdS. The reduction of crystallite size from 63 Å to 40 Å and the changes in lattice parameter confirmed the incorporation of Cu into Cd0.9Zn0.1S and generation of Cu related defects. The shift of absorption edge along upper wavelength region and elevated absorption intensity by Cu doping can be accredited to the collective consequence of quantization and the generation of defect associated states. The enhanced optical absorbance and the reduced energy gap recommended that Cd0.87Zn0.1Cu0.03S nanostructure is useful to enhance the efficiency of opto-electronic devices. The presence of Cd-S / Zn-Cd-S /Zn/Cu-Cd-S chemical bonding were confirmed by Fourier transform infrared investigation. The elevated green emissions by Cu incorporation was explained by decrease of crystallite size and creation of more defects. Zn, Cu dual doped CdS nanostructures are recognized as the possible and also efficient photo-catalyst for the removal dyes like methylene blue. The enhanced photo-catalytic behaviour of Zn, Cu dual doped CdS is the collective consequences of high density electron-hole pairs creation, enhanced absorbance in the visible wavelength, surface area enhancement, reduced energy gap and the formation of novel defect associated states. The stability measurement signified that Cu doped Cd0.9Zn0.1S exhibits superior dye removal ability and better stability even after 6 repetitive runs with limited photo-corrosion.

scholarly journals Assessing the Stability of Surface Lights for use in Retrievals of Nocturnal Atmospheric Parameters

2019 ◽  
Author(s):  
Jeremy E. Solbrig ◽  
Steven D. Miller ◽  
Jianglong Zhang ◽  
Lewis Grasso ◽  
Anton Kliewer
Keyword(s):  
Near Infrared ◽  
Correlation Coefficients ◽  
Visible Spectrum ◽  
Light Sources ◽  
Infrared Observations ◽  
Spatially Resolved ◽  
Relative Standard ◽  
Geometric Variables ◽  
The Stability

Abstract. Detection and characterization of aerosols is inherently limited at night due to a lack of sensitivity—information typically provided by visible spectrum observations. The VIIRS Day/Night Band (DNB) onboard the Suomi-NPP satellite is a first-of-its-kind calibrated sensor capable of collecting visible/near-infrared observations during both day and night. Multiple studies have suggested that anthropogenic light emissions such as those from cities and gas flares may be useable as light sources for retrieval of atmospheric properties including cloud and aerosol optical depth. However, their use in this capacity requires proper characterization of their intrinsic variation, which represents a source of retrieval uncertainty. In this study we use 18 months of cloud-cleared VIIRS data collected over five selected geographic domains to assess the stability of anthropogenic light emissions and their response to varied satellite and lunar geometries. Timeseries are developed for each location in each domain for DNB radiance, four infrared channels, and satellite and lunar geometric variables, and spatially-resolved correlation coefficients are computed between DNB radiance and each of the other variables. This analysis finds that while many emissive light sources are too unstable to be used reliably for atmospheric retrievals, some sources exhibit a sufficient stability (relative standard deviation

scholarly journals Handheld diffuse optical breast scanner probe for cross-sectional imaging of breast tissue

2019 ◽  
Vol 12 (02) ◽  
pp. 1950008 ◽  
Author(s):  
Majid Shokoufi ◽  
Farid Golnaraghi
Keyword(s):  
Breast Cancer ◽  
Breast Imaging ◽  
Breast Tissue ◽  
Reconstruction Algorithm ◽  
Breast Cancer Diagnosis ◽  
Array Detector ◽  
Light Sources ◽  
Compact Structure ◽  
Cross Sectional

Diffuse optical spectroscopy is a relatively new, noninvasive and nonionizing technique for breast cancer diagnosis. In the present study, we have introduced a novel handheld diffuse optical breast scan (DOB-Scan) probe to measure optical properties of the breast in vivo and create functional and compositional images of the tissue. In addition, the probe gives more information about breast tissue’s constituents, which helps distinguish a healthy and cancerous tissue. Two symmetrical light sources, each including four different wavelengths, are used to illuminate the breast tissue. A high-resolution linear array detector measures the intensity of the back-scattered photons at different radial destinations from the illumination sources on the surface of the breast tissue, and a unique image reconstruction algorithm is used to create four cross-sectional images for four different wavelengths. Different from fiber optic-based illumination techniques, the proposed method in this paper integrates multi-wavelength light-emitting diodes to act as pencil beam sources into a scattering medium like breast tissue. This unique design and its compact structure reduce the complexity, size and cost of a potential probe. Although the introduced technique miniaturizes the probe, this study points to the reliability of this technique in the phantom study and clinical breast imaging. We have received ethical approval to test the DOB-Scan probe on patients and we are currently testing the DOB-Scan probe on subjects who are diagnosed with breast cancer.

scholarly journals The influence of power electronic converter passive filter parameters for flicker in LED lighting

2018 ◽  
Vol 21 ◽  
pp. 00020
Author(s):  
Dariusz Sobczynski
Keyword(s):  
Power Systems ◽  
Supply Voltage ◽  
Current Source ◽  
Luminous Flux ◽  
Light Sources ◽  
Light Emitting ◽  
Current Voltage ◽  
Passive Filters ◽  
The Stability

The light emitting diodes (LEDs) are ever more used, and their price is getting lower year on year. Although, exchanging traditional light sources for the LED lamps does not seem to be complicated, we need to remember to maintaining high–quality of light. One of the aspects we should be worry about is a light’s flickering. Due to the shape of the current–voltage characteristics of the LED diode and their dependence on temperature, the value of the luminous flux – but also the lifetime – depends to a large extent on the stability of the supply voltage. Therefore, correct power system should be a thermally stable current source. Unfortunately, the simple power systems, equipped with passive filters are often used as cheap commercial solutions. In those types of systems stability of the output voltage is heavily dependent on the load conditions. Passive filters – usually consisting of coils and capacitors – are placed in the output circuit. This paper presents research carried out to show of filter capacitance influence on flickering phenomenon, and practical light’s flickering measuring technique for the LED lamps.

Low-temperature cross-linking of polyethyleneimine ethoxylated using silane coupling agents to obtain stable electron injection layers in solution-processed organic light-emitting devices

2019 ◽  
Vol 7 (22) ◽  
pp. 6759-6766 ◽  
Author(s):  
Satoru Ohisa ◽  
Dai Takashima ◽  
Takayuki Chiba ◽  
Junji Kido
Keyword(s):  
Low Temperature ◽  
Coupling Agents ◽  
Cross Linking ◽  
Silane Coupling Agents ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Organic Light ◽  
Silane Coupling ◽  
Organic Light Emitting Devices ◽  
The Stability

Cross-linking of polyethyleneimine ethoxylated using silane coupling agents improved the stability of organic light-emitting devices.

Study on Alkylation of Catechol with Ethanol by Al-P-Ti-O Oxides

2012 ◽  
Vol 599 ◽  
pp. 114-117 ◽  
Author(s):  
Xiao Mei Zhu ◽  
Bing Sun ◽  
Cheng Huo
Keyword(s):  
Citric Acid ◽  
Surface Area ◽  
Vapour Phase ◽  
Cane Sugar ◽  
Precipitation Method ◽  
Title Reaction ◽  
Catalytic Activities ◽  
P Content ◽  
The Stability ◽  
Ti Content

Vapour-phase alkylation of catechol with ethanol has been investigated over Al-P-Ti-O oxides prepared by non-uniform precipitation method. The catalytic activities decrease with the increase of P content. The catalytic activities increase with increasing Ti content, while the selectivity to guathol decreases. The results of XRD characterization demonstrate that the increase of titanium and the addition of additive affects the structure of the catalysts. The addition of additive (cane sugar or citric acid) decrease the catalytic activities of the catalysts, while increase the stability of the catalyst. Both the conversion of catechol and the selectivity to guathol decrease by the addition of additive, and the C-alkylation products increase obviously. The results indicate that the appropriate pores and surface area are enough for the title reaction, lager pore and higher surface area are favorable to C-alkylation products and stability of catalyst.

Solid-state thiolate-stabilized copper nanoclusters with ultrahigh photoluminescence quantum yield for white light-emitting devices

Nanoscale ◽  
2020 ◽  
Vol 12 (29) ◽  
pp. 15791-15799 ◽  
Author(s):  
Hao-Hua Deng ◽  
Qiong-Qiong Zhuang ◽  
Kai-Yuan Huang ◽  
Paramasivam Balasubramanian ◽  
Zhen Lin ◽  
...  
Keyword(s):  
Solid State ◽  
Quantum Yield ◽  
White Light ◽  
Copper Nanoclusters ◽  
Light Emitting ◽  
Aggregation Induced Emission ◽  
Emission Properties ◽  
Light Emitting Devices ◽  
Photoluminescence Quantum Yield

White-light-emitting devices are successfully fabricated by using solid-state copper nanoclusters as the sole phosphors with aggregation-induced emission properties.

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