scholarly journals Improvement of Solar PV Efficiency. Potential Materials for Organic Photovoltaic Cells

2013 ◽  
Vol 12 (1) ◽  
pp. 28-33
Author(s):  
Janis Latvels ◽  
Raitis Grzibovskis ◽  
Aivars Vembris ◽  
Dagnija Blumberga
Keyword(s):  
Absorption Spectra ◽  
Energy Gap ◽  
Spectral Response ◽  
Photovoltaic Cells ◽  
Threshold Energy ◽  
Organic Photovoltaic ◽  
Solar Pv ◽  
Optical Energy Gap ◽  
Response Range ◽  
Derivatives Of

Abstract Organic photovoltaic (OPV) cells are considered as a viable alternative to those energy sources currently in use. In this work three derivatives of original N,N’- dimetilaminobenziliden-1,3-indandione (DMABI) material are presented as potential materials for OPV. The photoconductivity threshold energy was evaluated from the perspective of spectral dependence of photoconductivity quantum efficiency, and the optical energy gap was defined to determine the optical absorption spectra. The absorption spectra of derivatives are blue shifted compared to original DMABI. Use of these derivatives in multilayer solar cells with original DMABI makes it possible to broaden the spectral response range of OPV.

Synthesis of some new heterocyclic azo dyes derived from 2-amino-3-cyano4.6-diarylpyridines and investigation of its absorption spectra and stability using the DFT

2020 ◽  
Vol 17 ◽  
Author(s):  
El-sayed M Abdelrehim
Keyword(s):  
Absorption Spectra ◽  
Elemental Analysis ◽  
Azo Dyes ◽  
Absorption Maximum ◽  
Density Functional ◽  
Energy Gap ◽  
Functional Theory ◽  
Mass Spectral ◽  
Chemical Reagents ◽  
Derivatives Of

Introduction: In continuation of our interest of 2-amino-3-cyano-4.6-diarylpyridines reactions in various fields of organic chemistry where we have previously used it in synthesis of many heterocyclic compounds [18-21] and where dyes generally have many applications especially when replacement of benzene or anthraquinone azo dyes with heterocyclic azo dyes so new derivatives of heterocyclic azo dyes derived from 2-amino-3-cyano-4.6-diarylpyridines were prepared. Materials and Methods: The IR spectra (KBr), NMR, elemental microanalyses and mass spectra spectrum, were performed at different faculties of science in Egypt. Absorption spectra were recorded on Unicam SP 750 in DMF and acetone using 1x 10-5 mol l-1 of dye concentration. Optimization was performed using density functional theory (DFT) and time dependent-DFT by applying Becke’s three-parameter hybrid exchange functional with Lee–Yang–Parr gradient-corrected correlation (B3LYP functional). The chemical reagents used in synthesis were purchased from Fluka, Sigma and Aldrich. Result and Discussions: The structure of the preparing Heterocyclic azo dyes is proved using spectroscopic tools and elemental analysis, and investigation of its absorption spectra indicates the effect of both solvent and substituent on absorption maximum. DFT calculations were performed on some the selected dyes. Conclusion: Structures of newly synthesized heterocyclic azo dyes were confirmed using elemental analysis, IR, 1H-NMR, 13CNMR and mass spectral data. DFT theory was used in explaining the electronic properties of the some selected dyes, where the energy gap can help in understanding the reactivity behaviour and stability of these compounds. Absorption spectra indicate the effect of both solvent and substituent on absorption maximum.

Absorption Spectra of Neodymium Doped Tellurite Glass

2014 ◽  
Vol 895 ◽  
pp. 395-399 ◽  
Author(s):  
Nur Amanina Mat Jan ◽  
M.R. Sahar ◽  
Sib Krishna Ghoshal ◽  
R. Ariffin ◽  
M.S. Rohani ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Urbach Energy ◽  
Energy Gap ◽  
Rare Earth Doping ◽  
Tellurite Glasses ◽  
X Ray Diffraction ◽  
Optical Energy Gap ◽  
Xrd Pattern ◽  
Optical Energy ◽  
Forbidden Transition

Modifying the optical and structural properties of tellurite glasses by controlling rare earth doping is an important issue. Neodymium doped magnesium-tellurite glasses of composition TeO2-MgO-Na2O with concentration from 0.5 to 2.5 mol% were synthesized by conventional melt-quenching technique. The amorphous natures of the glass were confirmed from x-ray diffraction (XRD) pattern. The absorption spectra (exhibits five bands) were recorded to determine the optical energy gap and Urbach energy. The values of the optical band gap are found to lie between 3.04-3.20 eV, while the Urbach energy values varies are between 0.21-0.12 eV. The optical energy gap for indirect forbidden transition has increased whereas the values of Urbach energy have decreased with the increasing of Nd2O3content. The structural and optical properties were found to be strongly affected by the varying concentration of Nd3+ions.

Heat Treatment at Different Temperatures and its Effect on the Optical Properties of Pure PMMA and PMMA-Coumarin

2021 ◽  
Vol 900 ◽  
pp. 42-47
Author(s):  
J.N. Zainab ◽  
Kareem Ali Jasim ◽  
Farah Jawad Kadhum ◽  
Auday H. Shaban
Keyword(s):  
Heat Treatment ◽  
Absorption Coefficient ◽  
Absorption Spectra ◽  
Optical Constant ◽  
Optical Constants ◽  
Energy Gap ◽  
Pmma Film ◽  
Pure Pmma ◽  
Optical Energy Gap ◽  
Different Temperatures

The effect of thermal treatment on optical constants of pure PMMA and with addition (15 and 35) ml of coumarin at different temperatures (100, 110 and 120) C0 for 1 hour were investigated. Cast method used to prepares films of pure PMMA and PMMA with (15 and 35) of coumarin. UV/VIS spectrometer technique used to measure the absorption spectra for these films. The optical constant (absorption spectra and absorption coefficient) don’t changes after applied temperatures in pure PMMA film but the optical constant (absorption spectra and absorption coefficient) in PMMA with (15 and 35) ml of coumarin increased with applied temperatures. The optical energy gap of pure PMMA and PMMA with (15 and 35) ml of coumarin slightly decreased after applied temperature up to 1200 C.

ON THE OPTICAL CHARACTERISTICS OF CdS THIN FILMS DEPOSITED BY QUASI-CLOSED VOLUME TECHNIQUE

2004 ◽  
Vol 18 (09) ◽  
pp. 1287-1297 ◽  
Author(s):  
MIHAELA RUSU ◽  
IULIA SALAORU ◽  
M. E. POPA ◽  
G. I. RUSU
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Electrical Conductivity ◽  
Temperature Dependence ◽  
Absorption Spectra ◽  
Energy Gap ◽  
Index Of Refraction ◽  
Closed Volume ◽  
Optical Energy Gap ◽  
Cds Thin Films

Cadmium sulfide (CdS) thin films (d=0.15–1.15 μ m ) were deposited onto glass substrates by the quasi-closed volume technique under vacuum. The investigations shown that the films are polycrystalline and have a hexagonal structure. It was experimentally established that the films with stable structure can be obtained if they are submitted to a heat treatment, consisting of several succesive heating/cooling cycles within a given temperature range (ΔT=300–600 K ), the temperature dependence of the electrical conductivity becomes reversible. For heat-treated samples, the values of thermal activation energy calculated from the temperature dependence of the electrical conductivity, ranged between 2.30–2.45 eV. The spectral dependences of the transmission and absorption coefficients were studied in the range 500–1400 nm. The influence of heat treatment on the shape of the absorption spectra and dispersion index of refraction is studied for samples with different thickness. Optical energy gap, calculated from the absorption spectra was in the range 2.30–2.5 eV.

Effect of the structural changes on the mechanical properties of the sintered films

2016 ◽  
Vol 12 (1) ◽  
pp. 4141-4144
Author(s):  
Garima Jain
Keyword(s):  
Crystallite Size ◽  
Lattice Constant ◽  
Structural Changes ◽  
Structural Investigation ◽  
Energy Gap ◽  
Lattice Parameter ◽  
Metal Chalcogenides ◽  
Optical Energy Gap ◽  
Tin Telluride ◽  
Physical Quantities

Polycrystalline films of tin telluride were prepared by sintering technique. The structural investigation of the films with different thicknesses enables to determine lattice parameter, crystallite size and strain existing in the films. The XRD traces showed that strain was tensile in nature. The crystallite size increases with thickness while strain decreases. Higher the value of tensile strain, larger is the lattice constant. The optical energy gap shows a descending nature with increasing strain and so with the lattice constant. Such an attempt made to delve into interdependence of basic physical quantities helps to explore the properties of SnTe and utilize it as an alternative to heavy metal chalcogenides in various technological applications.  

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