scholarly journals SYNTHESIS AND PHOTOVOLTAIC PROPERTIES OF SYMMETRIC BIS-AZOMETHINES WITH ACCEPTOR SUBSTITUENTS IN THE 4,4'-POSITION

2019 ◽  
pp. 36-39
Author(s):  
V. Ovdenko ◽  
D. Vyshnevskyi ◽  
S. Studzinsky ◽  
N. Davidenko
Keyword(s):  
Free Surface ◽  
Electric Potential ◽  
White Led ◽  
Photovoltaic Properties ◽  
Photoelectric Properties ◽  
Information Recording ◽  
Maximum Value ◽  
Chlorine Substitution ◽  
Blue Component ◽  
Photoinduced Changes

Two new symmetric azomethine dyes capable of photoinduced isomerization were synthesized by condensing symmetric bis-aldehyde (obtained by the reaction of epichlorohydrin with 4-oxybenzaldehyde) with 4-nitroaniline and 4-chloroaniline, respectively. The yield of the target products decreases with the transition from nitro-substituted azomethine to chlorine-substituted. This is due to the greater basicity of the starting amines with nitro-substitution when increasing the acceptor force of the substituent complicates the course of the reaction. Azomethines are characterized by absorption with a maximum at 400–410 nm, which makes them sensitive to radiation with a blue component of the spectrum. The photoelectric properties of azomethines upon irradiation were investigated by the method of measuring the surface potential with the help of a Kelvin dynamic probe. The maximum value of the electric potential of the photosensitive films free surface during irradiation with white LED at I = 60 W/m2 is about 270 mV in the case of azomethine with a nitro group in the 4,4' position and about 125 mV in the case of azomethine with chlorine as a substituent. That is, the magnitude of the electric potential of the free surface decreases approximately twice during the transition from nitro substituent to chlorine. This may be explained by the fact that the photoinduced changes in azomethine with a higher acceptor substituent flow more quickly and with greater efficiency. But at the same time, the reverse changes when turning off the light are just as fast. For chlorine substituted azomethine samples, the reverse process proceeds rather slowly, which may indicate greater stability over time of the photochemically modified form in case of chlorine substitution compared to the nitro-substituted analogue. Thus, the synthesized azomethines can be used in the development of new photovoltaic media and recording media for optical information recording.

Strain and electric field tunable photoelectric properties of multilayer Sb2Se3

2021 ◽  
Author(s):  
Wanxin Ding ◽  
Longhua Li
Keyword(s):  
Electric Field ◽  
Band Gap ◽  
Quantitative Relationship ◽  
Uniaxial Strain ◽  
Strain Property ◽  
Photovoltaic Properties ◽  
Electric Field Sensors ◽  
Photoelectric Properties ◽  
Photovoltaic Parameters ◽  
The Impact

Abstract Antimony selenide, Sb2Se3, has been attracted widespread attention in photovoltaic applications due to its high absorption coefficient and suitable band gap. However, the influence of uniaxial strain and electric field on the electronic and photovoltaic properties of multilayer Sb2Se3 is still unknown. Here, the quantitative relationship, such as strain-property, electric field-property, as well as thickness-property, is explored via first-principles calculations. Our results demonstrate that the band gap and photovoltaic parameters (Jsc, Voc, FF and PCE) of multilayer Sb2Se3 are not only affected by the uniaxial strain and electric field, but can also be tuned via the coupling of thickness with strain and electric field. The band-gap of multilayer Sb2Se3 is linear dependent on uniaxial strain and external electric field. We found that the effect of strain on the photovoltaic parameters could be negligible as compared with the effect of thickness. However, the effect of electric field is thickness dependent, 1 ‒ 2 layer(s) thin films are not affected while the impact of electric field increases with the increasing thickness. The quantitative strain (electric field)-properties relation of multilayer Sb2Se3 suggesting that Sb2Se3 films have a potential application in the field of strain and electric field sensors.

scholarly journals Light Harvesting and Optical-Electronic Properties of Two Quercitin and Rutin Natural Dyes

2019 ◽  
Vol 9 (12) ◽  
pp. 2567 ◽  
Author(s):  
Dongpeng Zhao ◽  
Qiuchen Lu ◽  
Runzhou Su ◽  
Yuanzuo Li ◽  
Meiyu Zhao
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Fourier Transforms ◽  
Light Harvesting ◽  
Absorption Peak ◽  
Conduction Band Edge ◽  
Photovoltaic Properties ◽  
Functional Theory ◽  
Photoelectric Properties ◽  
Reorganization Energies

The photovoltaic properties of two dyes (quercitin (Q) and rutin (R)) were experimentally investigated. The results showed that Q had excellent photoelectric properties with J s c of 5.480 mA·cm−2, V o c of 0.582 V, η of 2.151% larger than R with J s c of 1.826 mA·cm−2, V o c of 0.547 V, and η of 0.713%. For a better understanding of the photoelectric properties of two molecules and illustrating why the performances of Q is better than R from the micro-level, the UV-VIs spectrum, Fourier transforms infrared (FT-IR) spectrum, and cyclic voltage current characteristics were experimentally investigated. What is more, density functional theory (DFT) and time dependent density functional theory (TD-DFT) have been implemented in theoretical calculation. Based on the calculated results, frontier molecular orbitals (FMOs), charge differential density (CDD), infrared vibration, first hyperpolarizability, projected density orbital analysis (PDOS), electrostatic potential (ESP), and natural bond orbital (NBO) were analyzed. Hole/electron reorganization energies ( λ h / λ e ), light harvesting efficiency (LHE), fluorescent lifetime (τ), absorption peak, and the vertical dipole moment ( μ n o r m a l ) were calculated, and the shift of conduction band edge of a semiconductor (ΔECB) has been analyzed, which has a close relationship with J s c and V o c . The results demonstrated that, due to the higher LHE, τ, μ n o r m a l , and red-shifted absorption peak, Q has better photoelectric properties than R as a promising sensitizer.

Improved efficiency in dye sensitized solar cell (DSSC) by nano-MIL-101(Cr) impregnated photoanode

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ali Uğur ◽  
Arife Gencer Imer ◽  
Esra Kaya ◽  
Yaşar Karataş ◽  
Mehmet Gülcan
Keyword(s):  
Metal Organic Framework ◽  
High Surface ◽  
High Surface Area ◽  
Dye Sensitized Solar Cells ◽  
Optoelectronic Device ◽  
Device Fabrication ◽  
Solar Simulator ◽  
Photovoltaic Properties ◽  
Dye Sensitized ◽  
Photoelectric Properties

Abstract In the present work, MIL-101 nanoparticles (nano-MIL-101(Cr)) metal–organic framework (MOF) structure was synthesized by hydrothermal method, and characterized via Fourier transform infrared, X-ray diffraction, and scanning electron microscopy techniques. The optoelectronic application of MOFs was investigated for the first time. For this purpose, the dye-sensitized solar cells (DSSCs) consisting of the synthesized nano-MIL-101(Cr) impregnated photoanode (PA) was fabricated, and photovoltaic, photoelectric properties of them were investigated under different illumination intensities, and the obtained results were compared with reference one. The DSSC fabricated by impregnated PA showed better photovoltaic properties than reference one. It is obtained the power conversion efficiency (PCE) of about 0.828 and fill factor (ff) of 0.656 for the fabricated DSSC based on nano-MIL-101(Cr) impregnated PA under illumination power of 100 mW/cm2 by AM1.5 G solar simulator. For the reference DSSC, PCE, and ff is about 0.468 and 0.28, respectively. The PCE of the fabricated device based on nano-MIL-101(Cr) is ∼77% greater than the reference one. The improvement in the efficiency is because of good electrocatalytic activity, large pores, and high surface area of nano-MIL-101(Cr). The nano-MIL-101(Cr) can be used in organo-optoelectronic device fabrication to obtain better performance.

In Situ EXAFS Study of the Photoexcited State and Defects in Chalcogenide Glasses

MRS Bulletin ◽  
1999 ◽  
Vol 24 (1) ◽  
pp. 32-35 ◽  
Author(s):  
Alexander V. Kolobov ◽  
Hiroyuki Oyanagi ◽  
Kazunobu Tanaka
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Optical Absorption ◽  
Chalcogenide Glasses ◽  
Group Iv Semiconductors ◽  
Photoelectric Properties ◽  
Initial Stage ◽  
Good Review ◽  
Photoinduced Changes

Amorphous chalcogenides, of which selenium is the simplest representative, exhibit a number of unique properties such as the ability to undergo various transformations under the action of the bandgap light. On illumination, the absorption edge shifts to lower energies, and subsequent annealing near the glass-transition temperature leads to a recovery of the initial parameters as demonstrated in Figure 1. Such a photo-induced change could not be observed either in amorphous group IV semiconductors or a-As or in crystalline chalcogenides. A good review of the initial stage of these studies was made by de Neufville.Reversible photodarkening can also be observed in pure chalcogens, but this process can be achieved only at lower temperatures, which is understandable if one takes into account that the glass-transition temperature of selenium is just above room temperature. This result indicates that there is a correlation between the temperature at which photodarkening is annealed out and the flexibility of the glassy network.Reversible changes in the optical absorption are accompanied by (reversible) changes in electrical and photoelectric properties, volume, microhardness, glass-transition temperature, and dissolution rate in various solvents, to name a few. The totality of these changes has led investigators to the conclusion that the photoinduced changes in optical absorption are caused by changes in structure.

Dye adsorption mechanisms in TiO2 films, and their effects on the photodynamic and photovoltaic properties in dye-sensitized solar cells

2015 ◽  
Vol 17 (34) ◽  
pp. 21974-21981 ◽  
Author(s):  
Kyung-Jun Hwang ◽  
Wang-Geun Shim ◽  
Youngjin Kim ◽  
Gunwoo Kim ◽  
Chulmin Choi ◽  
...  
Keyword(s):  
Solar Cells ◽  
Adsorption Kinetics ◽  
Dye Sensitized Solar Cells ◽  
Dye Adsorption ◽  
Tio2 Films ◽  
Photovoltaic Properties ◽  
Adsorption Mechanisms ◽  
Dye Sensitized ◽  
Photoelectric Properties ◽  
Sensitized Solar Cells

The dye adsorption kinetics (and dye adsorption amounts) in DSSC have influenced the photoelectric properties and the photodynamic processes.

scholarly journals Flow caused by a point sink in a fluid having a free surface

1990 ◽  
Vol 32 (2) ◽  
pp. 231-249 ◽  
Author(s):  
Lawrence K. Forbes ◽  
Graeme C. Hocking
Keyword(s):  
Free Surface ◽  
Numerical Solution ◽  
Froude Number ◽  
Stagnation Point ◽  
Nonlinear Problem ◽  
Stagnation Line ◽  
Fully Nonlinear ◽  
Maximum Value ◽  
Low Froude Number ◽  
Nonlinear Solutions

AbstractThe flow caused by a point sink immersed in an otherwise stationary fluid is investigated. Low Froude number solutions are sought, in which the flow is radially symmetric and possesses a stagnation point at the surface, directly above the sink. A small-Froude-number expansion is derived and compared with the results of a numerical solution to the fully nonlinear problem. It is found that solutions of this type exist for all Froude numbers less than some maximum value, at which a secondary circular stagnation line is formed at the surface. The nonlinear solutions are reasonably well predicted by the small-Froude-number expansion, except for Froude numbers close to this maximum.

Nanocrystals of Nitrides and Oxides

2013 ◽  
Vol 24 ◽  
pp. 16-25
Author(s):  
Shinichi Kikkawa
Keyword(s):  
Thin Films ◽  
High Performance ◽  
Logic Gates ◽  
Iron Nitride ◽  
Recording Media ◽  
White Led ◽  
Nanosized Powders ◽  
Conducting Oxides ◽  
Transparent Conducting ◽  
Information Recording

Nanocrystals are important to attain high performance in optical & magnetic materials such as phosphors, laser emitters and information recording media. They are also required in future devices that involve magnetoresistance, logic gates, magnetic resonance and metamaterials. Nanocrystals of oxides and nitrides (and oxynitrides) were studied as nanosized powders, nanowires and dispersed granular thin films. Recent advancements of such nanocrystals prepared at Hokkaido University are introduced in this paper. Nanocrystals were prepared in transparent conducting oxides, white LED phosphor oxides and oxynitrides and magnetic iron nitride. Nanowires were grown in semiconducting gallium oxynitride and magnetic nanogranular thin films were prepared both in oxide and nitride.

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