Synthesis and characterization of novel copolymers based on carbazole and anthracene, for optoelectronic applications

The goal of this work is to study a new copolymer which combines the Ecbz properties and those Ant. First, we describe the route for preparing the new copolymer. Then, we report characterization measurements based on solid-state Nuclear Magnetic Resonance (CP-MAS 13C NMR), Raman, IR absorption, UV–visible absorption, photoluminescence spectroscopy, Scanning Electron Microscopy (SEM), and X-ray diffraction

Low cost microcontroller implementation of Takagi–Sugeno Fuzzy MPPT controller for photovoltaic systems

Maximum power point trackers have a significant role in optimizing the energy conversion efficiency in a photovoltaic system. The numeric achievements of MPPT algorithm can be implemented and tested by using several embedded boards as Digital Signal Processor, Field-Programmable Gate Array, Arduino, and dspace. Alternatively, for the low cost, availability and simplicity, the PIC microcontrollers can be used compared with the other hardware devices. Therefore, this paper presents the implementation of a Takagi–Sugeno fuzzy controller on a low cost PIC microcontroller, for tracking the maximum power point of a PV module. The PV system consists of a PV emulator, DC-DC converter, and resistive load. The different steps in design, simulation and realization of the T-S Fuzzy logic controller are discussed. The proposed controller system was evaluated by comparing its performance metrics, in terms of efficiency and the Integral Square Error, with existing technique in the literature. The results corresponding to the experimental validation show that the proposed MPPT controller is able to ensure a perfect tracking of the maximum power point with variation of irradiance and is performing better than reported in a previous work

Inhibition of copper corrosion by bipyrazole compound in aerated 3% NaCl

AbstractThe corrosion behaviour of copper in aerated 3% NaCl solution was investigated by rotating electrode at various rates. The reduction of O2 obeys the Levich equation. The inhibition of the copper corrosion in aerated 3% NaCl solution was studied by using potentiodynamic polarisation and linear polarisation resistance (LRP) in the presence of different concentrations of a bipyrazolic compound named N,N-bis (3-carbomethoxy-5-methylpyrazol-1-ylmethyl) cyclohexylamine (BiPyA). The presence of this compound in the solution decreases the corrosion current density and increases the linear resistance polarisation. The inhibition efficiencies obtained from cathodic Tafel plots and LRP methods are in good agreement. BiPyA compound presents an efficient inhibitor of copper corrosion, acts as a mixed-type inhibitor and adsorbs on the copper surface according to the Langmuir isotherm model

Tuning the electronic, photophysical and charge transfer properties of small D-A molecules based on Thienopyrazine-terthienyls by changing the donor fragment: A DFT study

Indexación: Scopus.Four acceptor-donor organic conjugated molecules based on thieno[3,4-b]pyrazine-terthienyls were analyzed in order to explore the effect of the donor substituent on their molecular structures, electronic and optical properties. Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD/DFT) calculations were carried out employing the B3LYP hybrid functional in combination with the 6-31G(d,p) basis set. The results suggests that the addition of electron-donating substituents to the conjugated molecules can diminish their energy gap value, which is beneficial to the photon harvesting. The lowest-lying absorption spectra of compounds substituted with electron donor groups exhibited a red-shift and a high oscillation factor compared with the unsubstituted molecule. Additionally, the ionization potential (IP), electron affinity (EA), reorganization energy (λ) and open-circuit voltage (Voc) of the molecules were evaluated. According to these values, the molecules show good photovoltaic properties, and efficient charge transfer for hole and electron and balanced charges.https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0717-97072017000303637&lng=en&nrm=iso&tlng=e

Optoelectronic properties of triphenylamine based dyes for solar cell applications. A DFT study

Indexación: Scopus.GSM thanks to the Department of Chemistry at the Universidad Andres Bello, Concepcion, Chile. LHMH gratefully acknowledges financial support from CONACYT (Projects CB2015-257823) and to the Universidad Autónoma del Estado de Hidalgo.Dye-sensitized solar cells (DSSCs) based on triphenylamine (TPA) as a donor group linked with the acceptor cyanoacrylic acid electron acceptor by 2,2'-bithiophene as π-bridged (D-π-A) has been investigated by Density Functional Theory (DFT) at the B3LYP/6-311G(d,p) level of theory, to establish the conformational orientation of cyanoacrylic acid group as well as evaluate the effect of planarizing the 2,2'-bithiophene unit in position 3 and 3' by electron withdrawing or donor groups on the electronic structure properties of ground and doping(n,p) states. Also, the Time Dependent Density Functional Theory (TD-DFT) at the CPCM-TD-CAM-B3LYP//CAM-B3LYP/6-311G(d,p) level of theory were selected to modulate the electronic absorption spectra and charge-transfer capabilities of the molecules analyzed in the present work. The results indicate that adding an auxiliary donor or withdrawing group to the 2,2'-bithiophene in the (D-π-A) arrangement allow to modify the LUMO's energy of the dyes, while the HOMO's energy is slightly affected. © 2018 Sociedade Brasileira de Quimica. All rights reserved.http://quimicanova.sbq.org.br/imagebank/pdf/AR20170232.pd

Etude comparative de l’élimination du Chrome en milieux aqueux par adsorption sur la pyrophyllite et la pyrophyllite traitée

La Pyrophyllite de la région de sud du Maroc, a été choisi comme adsorbant des ions Cr(III) en milieu aqueux. Á l’état brut comme à l’état modifié, la pyrophyllite a montré des caractéristiques favorables à l’élimination des ions étudiés. L’adsorption des ions étudiés serait soumise à un régime chimique, et représente un caractère exothermique. Le modèle de Langmuir à la fixation des ions étudiés sur la pyrophyllite brut et modifié, nous renseigne sur la nature et la texture de la surface du kaolin qui serait homogène, avec des sites énergétiquement identiques, capables de recevoir le cation Cr3+ en monocouche. Cette étude à été effectuée en variant plusieurs paramètres tels que le temps de la réaction (la cinétique) la masse de l’adsorbant et le pH. Les résultats obtenus ont montré que la quantité du chrome (III) adsorbé dans le cas de la pyrophyllite-modifiée est 4 fois plus grande que celle adsorbé dans le cas de la pyrophyllite naturelle. En effet le maximum d’adsorption (93.33 %) est atteint au bout de 30 min dans le cas de la pyrophyllite-Al, alors que dans le cas de la pyrophyllite naturelle le maximum d’adsorption (23 ,33 %) n’est atteint qu’après 90 minutes de contact