Tunable and ultra-stable UV light-switchable fluorescent composites for information hiding and storage

2018 ◽  
Vol 47 (32) ◽  
pp. 11264-11271 ◽  
Author(s):  
Mengxiao Li ◽  
Yu Feng ◽  
Qingyong Tian ◽  
Weijing Yao ◽  
Li Liu ◽  
...  
Keyword(s):  
Information Hiding ◽  
Uv Light ◽  
Hidden Information ◽  
Ambient Environment ◽  
Light Excitation ◽  
And Storage

Different information could be hidden and read under 365 nm and 254 nm light excitation, respectively. Moreover, the hidden information still can be identified after being exposed to an ambient environment for as long as 90 days.

Highly efficient green-emitting phosphor Sr4Al14O25:Ce,Tb with low thermal quenching and wide color gamut upon UV-light excitation for backlighting display applications

2020 ◽  
Author(s):  
Haoran Li ◽  
Yujun Liang ◽  
Shiqi Liu ◽  
Weilun Zhang ◽  
Yanying Bi ◽  
...  
Keyword(s):  
Performance Enhancement ◽  
Uv Light ◽  
Thermal Quenching ◽  
High Response ◽  
Color Gamut ◽  
Ultraviolet Excitation ◽  
Highly Efficient ◽  
Near Ultraviolet ◽  
Wide Color Gamut ◽  
Light Excitation

Highly-efficient and stable inorganic phosphors with high response to near-ultraviolet excitation are essential to the performance enhancement of the phosphor converted backlighting devices. Herein, highly-efficient green-emitting phosphors Sr4Al14O25:Ce,Tb (SAO:Ce3+,Tb3+) with...

ROOM TEMPERATURE PHOTOLUMINESCENCE OF POLYCRYSTALLINE SIC PREPARED FROM CARBON-SATURATED SI MELT

2002 ◽  
Vol 16 (06n07) ◽  
pp. 1047-1051
Author(s):  
JIANPING MA ◽  
ZHIMING CHEN ◽  
GANG LU ◽  
MINGBIN YU ◽  
LIANMAO HANG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Uv Light ◽  
X Ray Diffraction ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Composition And Structure ◽  
Light Excitation ◽  
Scanning Electron

Intense photoluminescence (PL) has been observed at room temperature from the polycrystalline SiC samples prepared from carbon-saturated Si melt at a temperature ranging from 1500 to 1650°C. Composition and structure of the samples have been confirmed by means of X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy. PL measurements with 325 nm UV light excitation revealed that the room temperature PL spectrum of the samples consists of 3 luminescent bands, the peak energies of which are 2.38 eV, 2.77 eV and 3.06 eV, respectively. The 2.38 eV band is much stronger than the others. It is suggested that some extrinsic PL mechanisms associated with defect or interface states would be responsible to the intensive PL observed at room temperature.

Syntheses, crystal structures and photoluminescence properties of two rare-earth molybdates CsLn(MoO4)2 (Ln=Eu, Tb)

2018 ◽  
Vol 233 (2) ◽  
pp. 73-79 ◽  
Author(s):  
Dan Zhao ◽  
Fa-Xue Ma ◽  
Bao-Zhong Liu ◽  
Yun-Chang Fan ◽  
Xue-Feng Han ◽  
...  
Keyword(s):  
Rare Earth ◽  
Uv Light ◽  
Layer Structure ◽  
Green Emission ◽  
Salt Flux ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Light Excitation ◽  
Rare Earth Molybdates

AbstractSingle crystals of two cesium rare-earth molybdates CsLn(MoO4)2(Ln=Eu, Tb) have been prepared using the high temperature molten salt (flux) method. Single-crystal X-ray diffraction analyses reveal that they crystallize in the orthorhombic space groupPccm(No. 49) and features a 2D layer structure that is composed of [Ln(MoO4)2]∞and [Cs]∞layers. Under near-UV light excitation, emission spectrum of CsEu(MoO4)2consists of several sharp lines due to the characteristic electronic transitions of Eu3+ions, whereas CsTb(MoO4)2exhibits characteristic green emission of Tb3+ions.

Evaluation of the Effect of Ultraviolet Light Excitation during Characterization of Silicon Carbide Epitaxial Layers

2018 ◽  
Vol 924 ◽  
pp. 261-264
Author(s):  
Hrishikesh Das ◽  
Swapna Sunkari ◽  
Oener Akdik ◽  
Andrei Konstantinov ◽  
Krister Gumaelius ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Ultraviolet Light ◽  
Defect Detection ◽  
Uv Light ◽  
Surface Treatments ◽  
Uv Laser ◽  
Original State ◽  
Optimal Surface ◽  
Light Excitation

The scanning of Silicon Carbide (SiC) epitaxy wafers for defects by ultraviolet (UV) laser or lamps is widely prevalent. In this work, we document the effects of UV light excitation on the SiC epitaxy material. An increase in background photoluminescence (PL) is observed after repeated scans. The effect of this increase on defect detection is shown. Optimal surface treatments to recover the material back to the original state are demonstrated. Further, some surface treatments are proposed which reduce the effect of the UV light excitation and prevent to a large extent the rise in background PL.

Hybrid Energy Conversion and Storage (HECS) Cells of the Composite Materials between Visible-Light Active Co(OH)2and UV-Light Active Ni(OH)2

2018 ◽  
Vol 85 (13) ◽  
pp. 1203-1217 ◽  
Author(s):  
Ketsuda Kongsawatvoragul ◽  
Saran Kalasina ◽  
Montakan Suksomboon ◽  
Nutthaphon Phattharasupakun ◽  
Juthaporn Wutthiprom ◽  
...  
Keyword(s):  
Composite Materials ◽  
Visible Light ◽  
Energy Conversion ◽  
Uv Light ◽  
Hybrid Energy ◽  
Energy Conversion And Storage ◽  
Visible Light Active ◽  
And Storage

scholarly journals Engineering Achiral Liquid Crystalline Polymers for Chiral Self-Recovery

2021 ◽  
Vol 22 (21) ◽  
pp. 11980
Author(s):  
Tengfei Miao ◽  
Xiaoxiao Cheng ◽  
Yilin Qian ◽  
Yaling Zhuang ◽  
Wei Zhang
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Uv Light ◽  
Helical Structure ◽  
Side Chain ◽  
Liquid Crystal Polymers ◽  
Polymeric Liquid ◽  
Crystalline Polymers ◽  
Liquid Crystal System ◽  
And Storage

Flexible construction of permanently stored supramolecular chirality with stimulus-responsiveness remains a big challenge. Herein, we describe an efficient method to realize the transfer and storage of chirality in intrinsically achiral films of a side-chain polymeric liquid crystal system by combining chiral doping and cross-linking strategy. Even the helical structure was destroyed by UV light irradiation, the memorized chiral information in the covalent network enabled complete self-recovery of the original chiral superstructure. These results allowed the building of a novel chiroptical switch without any additional chiral source in multiple types of liquid crystal polymers, which may be one of the competitive candidates for use in stimulus-responsive chiro-optical devices.

Tail-states induced appearance of conductor‑like behaviour in zinc‑tin‑oxide photo‑thinfilm transistors under sub-bandgap light excitation

2021 ◽  
Author(s):  
Soumen Dhara ◽  
Kham Niang ◽  
Andrew Flewitt ◽  
Arokia Nathan ◽  
Stephen Lynch
Keyword(s):  
Tin Oxide ◽  
Dark Current ◽  
Direct Evidence ◽  
Uv Light ◽  
Amorphous Structure ◽  
Persistent Photoconductivity ◽  
Current Analysis ◽  
Current Ratio ◽  
Zinc Tin Oxide ◽  
Light Excitation

Abstract We report on a strong persistent photoconductivity (PPC) induced appearance of conductor‑like behaviour in zinc-tin-oxide (ZTO) photo-thinfilm transistors (TFT). The active ZTO channel layer was prepared by remote-plasma reactive sputtering and possesses an amorphous structure. Under sub-bandgap excitation of ZTO with UV light, the photocurrent reaches as high as ~10-4 A (a photo-to-dark current ratio of ~107) and remains close to this high value after switching off the light. During this time, the ZTO TFT exhibits strong PPC with long-lasting recovery time, which leads the appearance of the conductor‑like behaviour in ZTO semiconductor. In the present case, the conductivity changes over six orders of magnitude, from ~10-7 to 0.92 Ω-1cm-1. After UV exposure, the ZTO compound can potentially remain in the conducting state for up to a month. The underlying physics of the observed PPC effect is investigated by studying defects (deep-states and tail-states) by employing a discharge current analysis (DCA) technique. Findings from the DCA study reveal direct evidence for the involvement of sub-gap tail-states of the ZTO in the strong PPC, while deep-states contribute to mild PPC.

K3Eu5(PO4)6: hydrothermal synthesis, crystal structure and photoluminescence properties

2019 ◽  
Vol 75 (7) ◽  
pp. 883-890 ◽  
Author(s):  
Ya-Li Xue ◽  
Ai-Yun Zhang ◽  
Xiao-Yang Han ◽  
Xiao-Qi Cui ◽  
Ling Deng ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrothermal Synthesis ◽  
Uv Light ◽  
Three Dimensional ◽  
Visible Region ◽  
Monoclinic Space Group ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Strong Luminescence ◽  
Light Excitation

An anhydrous orthophosphate, K3Eu5(PO4)6 (tripotassium pentaeuropium hexaphosphate), has been prepared by a high-temperature solid-state reaction combined with hydrothermal synthesis, and its crystal structure was determined by single-crystal X-ray diffraction analysis (SC-XRD). The results show that the compound crystallizes in the monoclinic space group C2/c and the structure features a three-dimensional framework of [Eu5(PO4)6]∞, with the tunnel filled by K+ ions. The IR spectrum, UV–Vis spectrum and luminescence properties of polycrystalline samples of K3Eu5(PO4)6, annealed at temperatures of 650, 700, 750, 800 and 850 °C, were investigated. Although with a full Eu3+ concentration (9.96 × 1021 ions cm−3), the self-activated phosphor K3Eu5(PO4)6 shows s strong luminescence emission intensity with a quantum yield of 37%. Under near-UV light excitation (393 nm), the series of samples shows the characteristic emissions of Eu3+ ions in the visible region from 575 to 715 nm. The sample sintered at 800 °C gives the strongest emission and its lifetime sintered at 800 °C (1.88 ms) is also the longest of all.

scholarly journals Luminescent and Scintillation Properties of CeAlO3 Crystals and Phase-Separated CeAlO3/CeAl11O18 Metamaterials

Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 296
Author(s):  
Oleg Sidletskiy ◽  
Pavlo Arhipov ◽  
Serhii Tkachenko ◽  
Iaroslav Gerasymov ◽  
Georgy Trushkovsky ◽  
...  
Keyword(s):  
Decay Time ◽  
Growth Process ◽  
Uv Light ◽  
Light Yield ◽  
Luminescence Decay ◽  
Crystalline Film ◽  
Time Value ◽  
Light Excitation ◽  
Single Crystalline Film ◽  
Α Particles

This work is dedicated to the growth process and investigation of luminescent and scintillation properties of CeAlO3 single crystals and CeAlO3/CeAl11O18 metamaterials under e-beam and α-particles excitation. It has been shown that cathodoluminescence and radioluminescence spectra of CeAlO3 crystals contain two bands, peaking at 440 and 500 nm, and caused by the Ce3+ 5d–4f transitions into CeAl11O18 phase, which is present in these crystals as an admixture. Under 270 nm ultraviolet (UV) light excitation, a CeAlO3 crystal possesses complicated non-exponential luminescence decay, with the average decay time of 16 ns. The light yield of CeAlO3 crystals under α-particle excitation is about 16% and 12%, in respect to the standard Bi4Ge3O12 (BGO) crystal and Y3Al5O12:Ce (YAG:Ce) single crystalline film samples, respectively. The CeAlO3 scintillation decay is quite fast, with the decay time value t1/e in the 54–56 ns range.

White Luminescence of Dy3+ Ions Doped 12CaO·7Al2O3 Nanopowders Under UV Light Excitation

2011 ◽  
Vol 11 (11) ◽  
pp. 9958-9963 ◽  
Author(s):  
Hancheng Zhu ◽  
Yuxue Liu ◽  
Duanting Yan ◽  
Xiaolei Yan ◽  
Chunguang Liu ◽  
...  
Keyword(s):  
Uv Light ◽  
Light Excitation ◽  
White Luminescence
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