scholarly journals Соmparative Study: Сatalytiс Aсtivity and Rhоdamine Dye Luminesсenсe at the Surfaсe оf TiО2-Based Nanоheterоstruсtures

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1758
Author(s):  
Elizaveta Kоnstantinоva ◽  
Vladimir Zaitsev ◽  
Artem Marikutsa ◽  
Alexander Ilin
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Energy Levels ◽  
Band Gaps ◽  
First Time

Nanоheterоstruсtures based оn titanium, mоlybdenum, tungsten, and vanadium nanооxides with symmetriс сrystal struсtures, mоrphоlоgies and high phоtосatalytic aсtivity in under illuminatiоn by visible light, have been synthesized and studied. Miсrоsсоpy, оptiсal speсtrоsсоpy, and eleсtrоn-spin resоnanсe teсhniques were used. The asymmetriс separatiоn оf phоtо-generated hоles and eleсtrоns between different nanооxides in their nanоheterоstruсtures suppresses their reсоmbinatiоn. Using the methоd develоped by the authоrs and based оn ESR speсtrоsсоpy, the energy levels оf the aсtive сenters inside the band gaps оf the studied samples were fоund. We have shоwn, fоr the first time, that under illuminatiоn оf nanоheterоstruсtures under asymmetriс соnditiоns with adsоrbed rhоdamine dye at the dye-absоrptiоn wavelength (500 nm), phоtосatalytiс reaсtiоns are mainly determined by light absоrptiоn by the nanоstruсtures themselves, and nоt by energy transfer frоm the dye. This impоrtant result shоws that high phоtосatalytiс aсtivity оf materials with symmetriс сrystal struсtures is the primary сriteriоn fоr сreating energy-effiсient phоtосatalysts. The results will be useful fоr the develоpment оf energy-effiсient сatalytiс deviсes based оn variоus соmbinatiоns оf metal nanооxides.

Comparison of photocatalytic activities of two kinds of lead magnesium niobate for decomposition of organic compounds under visible-light irradiation

2007 ◽  
Vol 22 (9) ◽  
pp. 2590-2597 ◽  
Author(s):  
Tetsuya Kako ◽  
Jinhua Ye
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Organic Compounds ◽  
Visible Light Irradiation ◽  
Band Gaps ◽  
Lead Magnesium Niobate ◽  
Light Irradiation ◽  
Photocatalytic Activities ◽  
Lead Magnesium ◽  
First Time

Two new oxide photocatalysts in the Pb–Mg–Nb ternary system, Pb3MgNb2O9 (PMN) and Pb1.83Mg0.29Nb1.71O6.39, have been synthesized, and their photophysical and photocatalytic properties were investigated for the first time. The band gaps of PMN and Pb1.83Mg0.29Nb1.71O6.39 were estimated to be 3.2 and 2.8 eV, respectively, from their absorption spectra. The photocatalytic activity evaluated from the decomposition of 2-propanol into acetone under visible-light irradiation indicated that Pb1.83Mg0.29Nb1.71O6.39 exhibited at least 20 times higher activity than PMN and has a strong oxidizing potential to mineralize organic compounds.

Photoluminescence Study of Energy Transfer Processes in Erbium Doped AlxGal−xAs Grown by MBE

1993 ◽  
Vol 301 ◽  
Author(s):  
Tong Zhang ◽  
J. Sun ◽  
N.V. Edwards ◽  
D.E. Moxey ◽  
R.M. Kolbas ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Energy Levels ◽  
Coupling Efficiency ◽  
Thermal Quenching ◽  
Energy Bands ◽  
Doped Semiconductors ◽  
Co Doping ◽  
Erbium Ions ◽  
Erbium Doped ◽  
First Time

ABSTRACTSharp photoluminescence from the intra-4f shell of Er3+ is observed from erbium doped AlxGal-xAs (0 ≤x ≤ 1) grown by molecular beam epitaxy. The intensity of the luminescence from the erbium is strongly dependent on the aluminum composition with a maximum at x ≈ 0.6. We will present a model that explains the variation in intensity based on the energy transfer coupling efficiency between the host semiconductor and the optically active erbium ions. The coupling efficiency is dominated by the alignment or misalignment of the erbium energy levels with the energy bands of the host semiconductor and by the excess carrier lifetime in the host. The data and model, which are presented here for the first time, are consistent with our previous work on the effects of co-doping with Be or Si and with other workers' measurements of thermal quenching in rare earth doped semiconductors.

Visible-Light Photosensitized Aryl and Alkyl Decarboxylative Carbon-Heteroatom and Carbon-Carbon Bond Formations

2019 ◽  
Author(s):  
Tuhin Patra ◽  
Satobhisha Mukherjee ◽  
Jiajia Ma ◽  
Felix Strieth-Kalthoff ◽  
Frank Glorius
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Alkyl Radical ◽  
General Strategy ◽  
Alkyl Radicals ◽  
Bond Forming ◽  
Radical Trapping ◽  
Carbon Carbon Bond ◽  
Radical Generation ◽  
Trapping Agent

<sub>A general strategy to access both aryl and alkyl radicals by photosensitized decarboxylation of the corresponding carboxylic acids esters has been developed. An energy transfer mediated homolysis of unsymmetrical sigma-bonds for a concerted fragmentation/decarboxylation process is involved. As a result, an independent aryl/alkyl radical generation step enables a series of key C-X and C-C bond forming reactions by simply changing the radical trapping agent.</sub>

scholarly journals New Transition and Energy Levels of Three-Times Ionized Krypton (Kr IV)

Atoms ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 48
Author(s):  
M. Raineri ◽  
M. Gallardo ◽  
J. Reyna Almandos ◽  
A. G. Trigueiros ◽  
C. J. B. Pagan
Keyword(s):  
Transition Probabilities ◽  
Energy Levels ◽  
Pulsed Discharge ◽  
Core Polarization ◽  
Polarization Effects ◽  
Hartree Fock ◽  
Theta Pinch ◽  
New Energy ◽  
First Time

A capillary pulsed-discharge and a theta-pinch were used to record Kr spectra in the region of 330–4800 Å. A set of 168 transitions of these spectra were classified for the first time. We extended the analysis to twenty-five new energy levels belonging to 3s23p24d, 3s23p25d even configurations. We calculated weighted transition probabilities (gA) for all of the experimentally observed lines and lifetimes for new energy levels using a relativistic Hartree–Fock method, including core-polarization effects.

scholarly journals An Indoor Visible Light Positioning System Using Tilted LEDs with High Accuracy

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 920
Author(s):  
Neha Chaudhary ◽  
Othman Isam Younus ◽  
Luis Nero Alves ◽  
Zabih Ghassemlooy ◽  
Stanislav Zvanovec ◽  
...  
Keyword(s):  
Visible Light ◽  
Polynomial Regression ◽  
Power Level ◽  
Least Square ◽  
Line Of Sight ◽  
Received Power ◽  
Strength Based ◽  
Complex Linear ◽  
Linear Least Square ◽  
First Time

The accuracy of the received signal strength-based visible light positioning (VLP) system in indoor applications is constrained by the tilt angles of transmitters (Txs) and receivers as well as multipath reflections. In this paper, for the first time, we show that tilting the Tx can be beneficial in VLP systems considering both line of sight (LoS) and non-line of sight transmission paths. With the Txs oriented towards the center of the receiving plane (i.e., the pointing center F), the received power level is maximized due to the LoS components on F. We also show that the proposed scheme offers a significant accuracy improvement of up to ~66% compared with a typical non-tilted Tx VLP at a dedicated location within a room using a low complex linear least square algorithm with polynomial regression. The effect of tilting the Tx on the lighting uniformity is also investigated and results proved that the uniformity achieved complies with the European Standard EN 12464-1. Furthermore, we show that the accuracy of VLP can be further enhanced with a minimum positioning error of 8 mm by changing the height of F.

scholarly journals First thermal studies on visible-light-switchable negative T-type photochromes of a nitrile-rich series

RSC Advances ◽  
2021 ◽  
Vol 11 (34) ◽  
pp. 21097-21103
Author(s):  
Mikhail Yu. Belikov ◽  
Mikhail Yu. Ievlev
Keyword(s):  
Thermal Stability ◽  
Visible Light ◽  
Temperature Effect ◽  
Thermal Studies ◽  
First Time ◽  
Thermal Stability Of

The temperature effect on the thermal stability of both the initial and photoinduced forms of nitrile-rich T-type photochromes was studied for the first time.

scholarly journals Extended analysis of Xe VII and Xe VIII

2017 ◽  
Vol 95 (9) ◽  
pp. 805-810 ◽  
Author(s):  
M. Raineri ◽  
M. Gallardo ◽  
J. Reyna Almandos ◽  
C.J.B. Pagan ◽  
R. Sarmiento
Keyword(s):  
Light Source ◽  
Energy Levels ◽  
Excited Configuration ◽  
Pulsed Discharge ◽  
Hartree Fock ◽  
The Core ◽  
New Energy ◽  
Extended Analysis ◽  
First Time ◽  
Atomic Parameters

A pulsed discharge light source to study the six and seven times ionized xenon spectra in the 419–4642 Å region was used. A set of 40 transitions of Xe VII and 25 transitions of Xe VIII were classified for the first time. We revised the values for the previously known energy levels and extended the analysis for Xe VII to 10 new energy levels belonging to 5s6d, 5s7s and 5s7p, 4d95s25p even and odd configurations, respectively. Seven new energy levels of the core excited configuration 4d95s5d of Xe VIII are presented. For the prediction of the atomic parameters, energy levels, and transition, relativistic Hartree–Fock calculations were used.

Synthesis of single-crystalline GeS nanoribbons for high sensitivity visible-light photodetectors

2015 ◽  
Vol 3 (31) ◽  
pp. 8074-8079 ◽  
Author(s):  
Changyong Lan ◽  
Chun Li ◽  
Yi Yin ◽  
Huayang Guo ◽  
Shuai Wang
Keyword(s):  
Visible Light ◽  
Vapor Deposition ◽  
High Performance ◽  
Incident Light ◽  
Chemical Vapor ◽  
High Sensitivity ◽  
Single Crystalline ◽  
Promising Application ◽  
Photo Detection ◽  
First Time

Single-crystalline GeS nanoribbons were synthesized by chemical vapor deposition for the first time. The nanoribbon photodetectors respond to the entire visible incident light with a response edge at around 750 nm and a high responsivity, indicating their promising application for high performance broadband visible-light photo-detection.

scholarly journals Photocatalytic Overall Water Splitting by SrTiO3 with Surface Oxygen Vacancies

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2572
Author(s):  
Yanfei Fan ◽  
Yan Liu ◽  
Hongyu Cui ◽  
Wen Wang ◽  
Qiaoyan Shang ◽  
...  
Keyword(s):  
Visible Light ◽  
Water Splitting ◽  
Oxygen Vacancies ◽  
Low Cost ◽  
Energy Levels ◽  
Light Response ◽  
Hydrogen Energy ◽  
Surface Oxygen ◽  
Carbon Reduction ◽  
Overall Water Splitting

Strontium Titanate has a typical perovskite structure with advantages of low cost and photochemical stability. However, the wide bandgap and rapid recombination of electrons and holes limited its application in photocatalysis. In this work, a SrTiO3 material with surface oxygen vacancies was synthesized via carbon reduction under a high temperature. It was successfully applied for photocatalytic overall water splitting to produce clean hydrogen energy under visible light irradiation without any sacrificial reagent for the first time. The photocatalytic overall water splitting ability of the as-prepared SrTiO3-C950 is attributed to the surface oxygen vacancies that can make suitable energy levels for visible light response, improving the separation and transfer efficiency of photogenerated carriers.

Sign in / Sign up

Export Citation Format

Share Document