scholarly journals The degradation of structure and luminescence in CsPbBr3 perovskite nanocrystals under UV light illumination

2018 ◽  
Author(s):  
Ji Li ◽  
Baoxue Bo ◽  
Xin Gao
Keyword(s):  
Uv Light ◽  
Light Illumination ◽  
Perovskite Nanocrystals ◽  
Degradation Of Structure

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

Optic and Piezoelectric Coupling in the Sol-Gel PLZT Electroceramics

2012 ◽  
Vol 730-732 ◽  
pp. 129-134
Author(s):  
Lucjan Kozielski ◽  
Malgorzata Plonska
Keyword(s):  
Uv Light ◽  
Sol Gel ◽  
Light Illumination ◽  
Piezoelectric Effects ◽  
Piezoelectric Coupling ◽  
Wireless Device ◽  
Organometallic Precursors ◽  
Gain Adjustment ◽  
Piezoelectric Transformers ◽  
Sintering Method

PZT ceramic system with presence of La contents, have been proposed and prepared using sol gel sintering method for practical application of photostriction, which is the superposition of photovoltaic and piezoelectric effects. Such a ceramics produced by conventional mixing oxide method does not exhibit photostrictive properties due to the defects and inhomogeneous distribution of grains and pores. In this study, an investigated lanthanium(III) doped PZT ceramics were obtained by sol-gel technique from the organometallic precursors. It was found that fabricated material were effective in the enhancement of photovoltaic and photostrictive properties. Consequently, lanthanium influence deviation of piezoelectric parameters were studied as a function UV light illumination. For the determination lighting dependancy of the transformation parameters the resonant and antiresonant method was implemented. The improved Piezoelectric Transformer structure successfully changed gain characteristics proportionally to light intensity. The authors invention of a light driven output gain adjustment in Piezoelectric Transformers (PT) yields a novel “smart” multifunctional wireless device. This new created application area can be utilized in self-adopting shutters in photo cameras due to improved sensitivity to surrounding illumination conditions.

Green-to-UV photon upconversion enabled by new perovskite nanocrystal-transmitter-emitter combination

Nanoscale ◽  
2021 ◽  
Author(s):  
Mio Koharagi ◽  
Naoyuki Harada ◽  
Keisuke Okumura ◽  
Junji Miyano ◽  
Shota Hisamitsu ◽  
...  
Keyword(s):  
Uv Light ◽  
Green Light ◽  
Perovskite Nanocrystals ◽  
Halide Perovskite ◽  
Lead Halide ◽  
Triplet Triplet Annihilation

The first example of triplet-triplet annihilation-based photon upconversion (TTA-UC) from green light to ultraviolet (UV) light sensitized by lead halide perovskite nanocrystals is demonstrated. The combination of a new transmitter...

scholarly journals Synthesis, Structural Characterization and Ligand-Enhanced Photo-Induced Color-Changing Behavior of Two Hydrogen-Bonded Ho(III)-Squarate Supramolecular Compounds

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1369 ◽  
Author(s):  
Wang ◽  
Ke ◽  
Feng ◽  
Ho ◽  
Chang ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Uv Light ◽  
Squaric Acid ◽  
Water Molecules ◽  
Light Illumination ◽  
Supramolecular Architecture ◽  
Bridging Ligands ◽  
Coordination Modes ◽  
Oxygen Atoms ◽  
Hydrogen Bonded

Two coordination polymers (CPs) with chemical formulas, [Ho2(C4O4)2(C2O4)(H2O)8]·4H2O (1) and [Ho(C4O4)1.5(H2O)3] (2), (C4O42− = dianion of squaric acid, C2O42− = oxalate), have been synthesized and their structures were determined by single-crystal X-ray diffractometer (XRD). In compound 1, the coordination environment of Ho(III) ion is eight-coordinate bonded to eight oxygen atoms from two squarate, one oxalate ligands and four water molecules. The squarates and oxalates both act as bridging ligands with 1,2-bis-monodentate and bis-chelating coordination modes, respectively, connecting the Ho(III) ions to form a one-dimensional (1D) ladder-like framework. Adjacent ladders are interlinked via O–HO hydrogen bonding interaction to form a hydrogen-bonded two-dimensional (2D) layered framework and then arranged orderly in an AAA manner to construct its three-dimensional (3D) supramolecular architecture. In compound 2, the coordination geometry of Ho(III) is square-antiprismatic eight coordinate bonded to eight oxygen atoms from five squarate ligands and three water molecules. The squarates act as bridging ligands with two coordination modes, 1,2,3-trismonodentate and 1,2-bis-monodentate, connecting the Ho(III) ions to form a 2D bi-layered framework. Adjacent 2D frameworks are then parallel stacked in an AAA manner to construct its 3D supramolecular architecture. Hydrogen bonding interactions between the squarate ligands and coordinated water molecules in 1 and 2 both play important roles on the construction of their 3D supramolecular assembly. Compounds 1 and 2 both show remarkable ligand-enhanced photo-induced color-changing behavior, with their pink crystals immediately turning to yellow crystals under UV light illumination.

scholarly journals Hydrazine-modified Zn-oxysulfide nanoparticles for CO2 reduction under low UV-light illumination

2019 ◽  
Vol 1230 ◽  
pp. 012039
Author(s):  
Hairus Abdullah ◽  
Noto Susanto Gultom ◽  
Dong-Hau Kuo ◽  
Albert Daniel Saragih
Keyword(s):  
Uv Light ◽  
Co2 Reduction ◽  
Light Illumination

scholarly journals Visible-Light-Induced Bactericidal Activity of a Nitrogen-Doped Titanium Photocatalyst against Human Pathogens

2006 ◽  
Vol 72 (9) ◽  
pp. 6111-6116 ◽  
Author(s):  
Ming-Show Wong ◽  
Wen-Chen Chu ◽  
Der-Shan Sun ◽  
Hsuan-Shun Huang ◽  
Jiann-Hwa Chen ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Visible Light ◽  
Bactericidal Activity ◽  
Uv Light ◽  
Shigella Flexneri ◽  
Light Illumination ◽  
Human Pathogens ◽  
Carbon Doped ◽  
Nitrogen Doped ◽  
Visible Light Illumination

ABSTRACT The antibacterial activity of photocatalytic titanium dioxide (TiO2) substrates is induced primarily by UV light irradiation. Recently, nitrogen- and carbon-doped TiO2 substrates were shown to exhibit photocatalytic activities under visible-light illumination. Their antibacterial activity, however, remains to be quantified. In this study, we demonstrated that nitrogen-doped TiO2 substrates have superior visible-light-induced bactericidal activity against Escherichia coli compared to pure TiO2 and carbon-doped TiO2 substrates. We also found that protein- and light-absorbing contaminants partially reduce the bactericidal activity of nitrogen-doped TiO2 substrates due to their light-shielding effects. In the pathogen-killing experiment, a significantly higher proportion of all tested pathogens, including Shigella flexneri, Listeria monocytogenes, Vibrio parahaemolyticus, Staphylococcus aureus, Streptococcus pyogenes, and Acinetobacter baumannii, were killed by visible-light-illuminated nitrogen-doped TiO2 substrates than by pure TiO2 substrates. These findings suggest that nitrogen-doped TiO2 has potential application in the development of alternative disinfectants for environmental and medical usages.

scholarly journals Sheet-on-belt branched TiO2(B)/rGO powders with enhanced photocatalytic activity

2018 ◽  
Vol 9 ◽  
pp. 1550-1557 ◽  
Author(s):  
Huan Xing ◽  
Wei Wen ◽  
Jin-Ming Wu
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Charge Separation ◽  
Reaction Rate ◽  
Uv Light ◽  
Three Dimensional ◽  
Reaction Rate Constant ◽  
Light Illumination ◽  
Reduced Graphene

TiO2(B) is usually adopted to construct phase junctions with anatase TiO2 for applications in photocatalysis to facilitate charge separation; its intrinsic photocatalytic activity, especially when in the form of one- or three-dimensional nanostructures, has been rarely reported. In this study, a sheet-on-belt branched TiO2(B) powder was synthesized with the simultaneous incorporation of reduced graphene oxide (rGO). The monophase, hierarchically nanostructured TiO2(B) exhibited a reaction rate constant 1.7 times that of TiO2(B)/rGO and 2.9 times that of pristine TiO2(B) nanobelts when utilized to assist the photodegradation of phenol in water under UV light illumination. The enhanced photocatalytic activity can be attributed to the significantly increased surface area and enhanced charge separation.

scholarly journals Tunable Šolc-type filter in periodically poled LiNbO3by UV-light illumination

2006 ◽  
Vol 14 (13) ◽  
pp. 6279 ◽  
Author(s):  
Jianhong Shi ◽  
Jinghe Wang ◽  
Lijun Chen ◽  
Xianfeng Chen ◽  
Yuxing Xia
Keyword(s):  
Uv Light ◽  
Light Illumination ◽  
Periodically Poled

scholarly journals Synthesis of g-C3N4-Decorated ZnO Porous Hollow Microspheres for Room-Temperature Detection of CH4 under UV-Light Illumination

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1507 ◽  
Author(s):  
Min Xiao ◽  
Yanwei Li ◽  
Bo Zhang ◽  
Guang Sun ◽  
Zhanying Zhang
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Uv Light ◽  
Response Speed ◽  
Hollow Microspheres ◽  
Oxide Semiconductor ◽  
Light Illumination ◽  
Long Term Stability ◽  
Temperature Detection ◽  
Good Repeatability

UV light-assisted gas sensors based on metal oxide semiconductor (MOS) have attracted much attention in detecting flammable and explosive gases at room temperature. In this paper, graphite-based carbon nitride (g-C3N4) nanosheets-decorated ZnO porous hollow microspheres (PHMSs) with the size about 3~5 μm in diameter were successfully synthesized by annealing the solvothermally-synthesized Zn5(CO3)2(OH)6 PHMSs together with g-C3N4. The synthesized samples were characterized by XRD, SEM, TEM, FT-IR and XPS. The results indicated that the prepared g-C3N4/ZnO PHMSs were constructed by numerous loosely stacked ZnO nanoparticles of 20~30 nm in diameter. Gas sensing tests indicated that under UV light (365~385 nm) illumination, the sensors fabricated with g-C3N4/ZnO HPMSs showed an enhanced response and faster response speed than the pure ZnO counterpart at room temperature. In addition, the g-C3N4/ZnO sensor also exhibited good repeatability and long-term stability for CH4 detection.

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