scholarly journals Disinfection mechanism of the photocatalytic activity of SnO2 thin films against Candida albicans, proposed from the experimental and simulated perspective

2021 ◽  
Author(s):  
Alejandro Faudoa-Arzate ◽  
Javier Camarillo-Cisneros ◽  
Alva Rocío Castillo-González ◽  
María Alejandra Favila-Pérez ◽  
Renee Joselin Sáenz-Hernández ◽  
...  
Keyword(s):  
Thin Films ◽  
Photocatalytic Activity ◽  
Candida Albicans ◽  
Density Functional ◽  
Uv Light ◽  
Functional Theory ◽  
Colony Forming Units ◽  
The Density Functional Theory ◽  
Important Health ◽  
Sno2 Thin Films

Background: Nosocomial infections are important health problems and a cause of complications and death in hospitalized patients. This problem should be solved from the preventive angle, avoiding the spread of infections by designing disinfection methods based on the photocatalytic activity of semiconductor materials like Tin Oxide (SnO2). Methods: Antimicrobial activity of UV light was tested using Candida albicans ATCC10231 inoculation of SnO2 thin films by counting colony forming units (UFC). Interaction of UV light with SnO2 was analyzed by the Density Functional Theory (DFT) and the extension to Hubbard model (DFT+U) schemes to predict the electrons behavior in a subatomic level. Results: After exposure to UV light, C. albicans had a reduction of 36.5% of viable cells, and when SnO2 was included, cells were reduced by 60.2%. Measures of the electronics structure obtained by the first principle calculations under the DFT and DFT+U schemes showed that O-p orbitals mediate the oxidation process in the bulk semiconductor. By including the surface effects when cleaving the (1 0 0) plane, the three orbitals O-p, Sn-p, and Sn-s are the mediators. Conclusions: SnO2 films are promising antimicrobial coatings because UV light has a synergic activity with thin films, resulting in a faster disinfection.

scholarly journals A Solid-State Fluorescence Switch Based on Triphenylethene-Functionalized Dithienylethene With Aggregation-Induced Emission

2021 ◽  
Vol 9 ◽  
Author(s):  
Haining Zhang ◽  
Xiaoxiao Hu ◽  
Huijuan Zhu ◽  
Limin Shen ◽  
Congmin Liu ◽  
...  
Keyword(s):  
Solid State ◽  
Visible Light ◽  
Density Functional ◽  
Uv Light ◽  
Functional Theory ◽  
Aggregation Induced Emission ◽  
H Nmr ◽  
Chemical Structures ◽  
Fluorescence Switch ◽  
The Density Functional Theory

The development of novel dithienylethene-based fluorescence switches in the aggregated state, and the solid state is highly desirable for potential application in the fields of optoelectronics and photopharmacology. In this contribution, three novel triphenylethene-functionalized dithienylethenes (1–3) have been designed and prepared by appending triphenylethene moieties at one end of dithienylethene unit. Their chemical structures are confirmed by 1H NMR, 13C NMR, and HRMS (ESI). They display good photochromic behaviors with excellent fatigue resistance upon irradiation with UV or visible light in Tetrahydrofuran (THF) solution. Before irradiation with UV light, they exhibit Aggregation Induced Emission (AIE) properties and luminescence behaviors in the solid state. Moreover, upon alternating irradiation with UV/visible light, they display effective fluorescent switching behaviors in the aggregated state and the solid state. The experimental results have been validated by the Density Functional Theory (DFT) calculations. Thus, they can be utilized as novel fluorescence switches integrated in smart, solid-state optoelectronic materials and photopharmacology.

scholarly journals Trinuclear Oxo-Titanium Clusters: Synthesis, Structure, and Photocatalytic Activity

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3195 ◽  
Author(s):  
Maciej Janek ◽  
Tadeusz M. Muzioł ◽  
Piotr Piszczek
Keyword(s):  
Photocatalytic Activity ◽  
Density Functional ◽  
Diffuse Reflectance ◽  
Environmental Pollutants ◽  
Dft Method ◽  
Functional Theory ◽  
Optical Band Gaps ◽  
Oxo Complexes ◽  
The Density Functional Theory ◽  
Activity Estimation

The interest in titanium (IV) oxo-complexes is due to their potential application in photodegradation processes and environmental pollutants reduction. Titanium (IV) oxo-complexes (TOCs) of the general formula [Ti3O(OiPr)8(OOCR’)2] (R’ = -C13H9 (1), -p-PhCl (2), -m-PhNO2 (3), -C4H7 (4)) were synthesized and structurally characterized. The use of the different carboxylate ligands allowed modulating the optical band gaps of the produced microcrystals, which were measured via diffuse reflectance ultraviolet and visible spectroscopy (UV-Vis-DRS) and calculated using the density functional theory (DFT) method. The dispersion of TOCs (1–3) in the poly (methyl methacrylate) matrix (PMMA) led to the formation of polymer/TOCs composites, which in the next stage of our works have been applied in the photocatalytic activity estimation of synthesized trinuclear Ti(IV) oxo-complexes. Studies of the photocatalytic degradation of methylene blue (MB) induced by UV irradiation exhibit that the PMMA-TOCs composite containing (1) oxo-clusters is the most active, followed by the system containing the complex (3).

A strategy for enhancing the photoactivity of g-C3N4-based single-atom catalysts via sulphur doping: a theoretical study

2021 ◽  
Vol 23 (11) ◽  
pp. 6632-6640
Author(s):  
Yanqing Guo ◽  
Meng Xia ◽  
Mingkun Zhang ◽  
Jing Zou ◽  
Yue You ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Photocatalytic Activity ◽  
Density Functional ◽  
Carbon Nitride ◽  
Theoretical Study ◽  
Density Functional Theory Calculations ◽  
Graphitic Carbon Nitride ◽  
Single Atom ◽  
Functional Theory ◽  
The Density Functional Theory

The sulphur-doping strategy was proposed to enhance the incorporation of single Pt atoms in monolayer graphitic carbon nitride and the density functional theory calculations verified it has superb photocatalytic activity.

scholarly journals Synthesis, Characterization, and Photocatalysis of Fe-Doped : A Combined Experimental and Theoretical Study

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Liping Wen ◽  
Baoshun Liu ◽  
Xiujian Zhao ◽  
Kazuya Nakata ◽  
Taketoshi Murakami ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Density Functional ◽  
Theoretical Study ◽  
Iron Nitrate ◽  
Fe Doping ◽  
Theoretical Computation ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Recombination Centers ◽  
Fe Ions

Fe-doped TiO2was prepared by hydrothermal treating Ti peroxide sol with different amount of iron nitrate. Fe ions can enter TiO2lattice by substituting Ti4+ions, which significantly affect the crystallinity and morphology of TiO2nanoparticles. Fe doping also influences the UV-Vis absorption and photoluminescence of TiO2, due to the change of electronic structure. It is shown that Fe ions are more easily doped on TiO2surface than in bulk. The theoretical computation based on the density functional theory (DFT) shows that the Fe ions in TiO2bulk are localized and mainly act as the recombination centers of photoinduced electrons and holes. Some results support that the Fe3+ions on surface can form intermediate interfacial transfer pathway for electrons and holes, which is beneficial for increasing the photocatalytic activity of TiO2. The photocatalytic activity first increases and then decreases as the Fe concentration increases, which is coaffected by the bulk-doped and surface-doped Fe ions.

Morphology Control of Zirconia Thin Films Prepared Using Photochromic Precursors

2007 ◽  
Vol 350 ◽  
pp. 133-136
Author(s):  
Kaori Nishizawa ◽  
Haruhiko Fukaya ◽  
Takeshi Miki ◽  
Kazuyuki Suzuki ◽  
Kazumi Kato
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Uv Irradiation ◽  
Density Functional ◽  
Dft Calculation ◽  
Precursor Solution ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Precursor Structure ◽  
The Difference

A new photochromic ZrO2 precursor solution was prepared using zirconium tetra-n-butoxide, 4-(phenylazo)benzoic acid and ethyleneglycol monomethylether. The density functional theory (DFT) calculation has identified that the structure of the synthesized precursor molecule changed by UV irradiation. The two kinds of thin films were prepared using the photosensitive ZrO2 precursor solution without and with UV irradiation. The surface morphology of thin films changed by UV irradiation. It was found that the surface morphology of thin films is controlled by the difference of precursor structure introduced by UV irradiation.

First-Principle Study of Electronic Structure and Enhanced Visible-Light Photocatalytic Activity of Anatase TiO2 through C and F Codoping

2013 ◽  
Vol 746 ◽  
pp. 400-405 ◽  
Author(s):  
Zong Bao Li ◽  
Xia Wang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Density Functional ◽  
Light Response ◽  
Functional Theory ◽  
Visible Light Photocatalytic Activity ◽  
Visible Light Response ◽  
The Density Functional Theory ◽  
Visible Light Photocatalytic

The large intrinsic band gap in TiO2has hindered severely its potential application for visible-light irradiation, while anion doping has led to decreases in visible-light photocatalytic activity in spite of narrowing the host band gap. In this study, we have used cation-passivated codoping of (C, F), (C, 2F) and (2C, F) to modify the band edges of anatase TiO2to extend absorption to longer visible-light wavelegenths using the density functional theory based on GGA + U method. The results indicate that the codoping of C/F=1/1 cases have much more efficient and stable photocatalyst than pristine one and the others, which narrow the band gaps and realize the visible-light response activities.

Thermodynamic Stability of Hexagonal and Rhombohedral Bn at Cvd Conditions from Van der Waals Corrected First Principles Calculations

2019 ◽  
Author(s):  
Henrik Pedersen ◽  
Björn Alling ◽  
Hans Högberg ◽  
Annop Ektarawong
Keyword(s):  
Thin Films ◽  
Thermodynamic Stability ◽  
First Principles ◽  
Thermal Equilibrium ◽  
Density Functional ◽  
Van Der Waals ◽  
Chemical Vapor ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Stability

Thin films of boron nitride (BN), particularly the sp<sup>2</sup>-hybridized polytypes hexagonal BN (h-BN) and rhombohedral BN (r-BN) are interesting for several electronic applications given band gaps in the UV. They are typically deposited close to thermal equilibrium by chemical vapor deposition (CVD) at temperatures and pressures in the regions 1400-1800 K and 1000-10000 Pa, respectively. In this letter, we use van der Waals corrected density functional theory and thermodynamic stability calculations to determine the stability of r-BN and compare it to that of h-BN as well as to cubic BN and wurtzitic BN. We find that r-BN is the stable sp<sup>2</sup>-hybridized phase at CVD conditions, while h-BN is metastable. Thus, our calculations suggest that thin films of h-BN must be deposited far from thermal equilibrium.

scholarly journals Strain Investigation on Spin-Dependent Transport Properties of γ-Graphyne Nanoribbon Between Gold Electrodes

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yun Li ◽  
Xiaobo Li ◽  
Shidong Zhang ◽  
Liemao Cao ◽  
Fangping Ouyang ◽  
...  
Keyword(s):  
Transport Properties ◽  
High Performance ◽  
Density Functional ◽  
Strain Engineering ◽  
Molecular Junctions ◽  
Spin Splitting ◽  
Functional Theory ◽  
Spin Dependent Transport ◽  
The Density Functional Theory ◽  
Dependent Transport

AbstractStrain engineering has become one of the effective methods to tune the electronic structures of materials, which can be introduced into the molecular junction to induce some unique physical effects. The various γ-graphyne nanoribbons (γ-GYNRs) embedded between gold (Au) electrodes with strain controlling have been designed, involving the calculation of the spin-dependent transport properties by employing the density functional theory. Our calculated results exhibit that the presence of strain has a great effect on transport properties of molecular junctions, which can obviously enhance the coupling between the γ-GYNR and Au electrodes. We find that the current flowing through the strained nanojunction is larger than that of the unstrained one. What is more, the length and strained shape of the γ-GYNR serves as the important factors which affect the transport properties of molecular junctions. Simultaneously, the phenomenon of spin-splitting occurs after introducing strain into nanojunction, implying that strain engineering may be a new means to regulate the electron spin. Our work can provide theoretical basis for designing of high performance graphyne-based devices in the future.

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