Marco Antonio Meneses-Nava

Synthesis and non-linear optical characterization of novel borinate derivatives of cinnamaldehyde

Herein is reported the synthesis of three new borinates (2a–2c) derived from bidentate imine ligands (1a–1c), which were prepared from the corresponding cinnamaldehyde derivatives. All compounds were characterized by MS, IR and NMR spectroscopy. The nonlinear optical (NLO) characterization of these molecules having push–pull properties is included. Second order nonlinearities were evaluated at 1.907 μm by the electric-field-induced second harmonic (EFISH) technique through the β×μ product, showing a trend for a general increase of the NLO response after boron complexation. For borinate 2c, which has strong electron-donating and electron-withdrawing groups at opposite ends of the π-backbone, βμ = 1560 × 10−30 D cm5 esu−1, showing a three-fold increase with respect to the ligand 1c (βμ = 542 × 10−30 D cm5 esu−1). Third-order nonlinearities, in solid films, were evaluated employing the third harmonic generation (THG) Maker Fringe technique showing χ(3) susceptibilities of the order of χ(3)∼10−12 esu at the infrared wavelength of 1.2 μm. Compounds with the highest χ(3) values correspond to those having the largest βμ product: for 1cχ(3) = 1.1 × 10−11 esu and for 2cχ(3) = 8.4 × 10−12 esu.

SEMICONDUCTOR POLYMER/TOP ELECTRODE INTERFACE GENERATED BY TWO DEPOSITION METHODS AND ITS INFLUENCE ON ORGANIC SOLAR CELL PERFORMANCE

In this Research Article, the effect of two techniques for top-electrode deposition in organic photovoltaics (OPVs) cells with the configuration ITO/PEDOT:PSS/PTB7-Th:PC71BM/PFN/top-electrode is analyzed. One deposition was made by evaporation under high vacuum, meanwhile the other was carried out at normal room atmosphere; for the former, a double layer of Ca and the eutectic alloy Fields metal (FM) was thermally evaporated, while for the latter FM was deposited just by melting and dropping it on top of the delimited active area at temperatures about 90 °C. The average short-circuit photocurrent density, open circuit voltage and fill factor for devices with either Ca/FM (evaporated) or FM (by dripping) cathode, were very similar: around 13.20 mA/cm2, 840 mV, and 0.6, respectively. Average efficiency for devices with the mentioned evaporated cathode was of 6.4% (largest value 7.0%), meanwhile for devices with the cathode deposited by dripping, it was of 6.1% (largest value 6.5%). Morphological analysis, by atomic force microscopy on the surface of a FM electrode, detached from an OPV device, shows inhomogeneities and pinholes in its surface with an average roughness of 16 nm. OPV photocurrent was studied by means of laser beam induced current (LBIC), it showed that OPVs devices with FM top electrode exhibits an inhomogeneous response. An impedance analysis was also carried out and results were correlated with defects observed at the studied interface. In spite of the mentioned deficiencies at FM interface, overall PV performance of devices with this electrode highlights the convenience of using FM because of its easy, fast, and low-cost deposition (vacuum free) characteristics.

Fast and environmentally friendly quantitative analysis of active agents in anti-diabetic tablets by an alternative laser-induced breakdown spectroscopy (LIBS) method and comparison to a validated reversed-phase high-performance liquid chromatography (RP-HPLC) method.

Laser-induced breakdown spectroscopy (LIBS) is evaluated as a potential analytic technique for rapid screening and quality control of anti-diabetic tablets. This paper proposes a simple LIBS-based method for the quantitative analysis of two active pharmaceutical ingredients (APIs): metformin (Met) and glybenclamide (Gly). In order to quantify both APIs, chlorine (Cl) concentration was estimated by employing the Cl/Br optical emission ratio, where Br was introduced as internal standard. Calibration curves were prepared, achieving linearity higher than 99%. On the other hand, for comparison to the proposed method, an isocratic reversed-phase high-performance liquid chromatography (RP-HPLC) method was also developed for quantitative determination of the same analytes by ultraviolet (UV) detection. The chromatographic separation was achieved on a Phenomenex Hypersil C18, 250 mm X 4.6 mm, 5 μm column. The mobile phase was K2HPO4/H3PO4-CH3OH and flow rate was 1.0 mL min−1. The method is linear over a range of 10-60 μg mL−1 for Gly and 5-30 μg mL−1 for Met and the correlation coefficients were >0.99. Recoveries were found to be in the range of 95-101%. Furthermore, four different commercial brands of each active agent were evaluated by both proposed LIBS and chromatographic methods and results were compared with each other. The comparison was satisfactorily validated by analysis of variance (ANOVA).

White light emission from an exciplex interface with a single emitting layer (Conference Presentation)

Efficient solid state lighting devices based in inorganic emissive materials are now available in the market meanwhile for organic emissive materials still a lot of research work is in its way. [1,2] In this work a new organic emissive material based on carbazole, N-(4-Ethynylphenyl) carba-zole-d4 (6-d4), is used as electron-acceptor and commercial PEDOT:PSS as the electron-donor to obtain white emission. Besides the HOMO-LUMO levels of materials the white emission showed dependence on the films thicknesses and applied voltages. In here it is reported that by diminishing the thickness of the PEDOT:PSS layer, from 60 to 35 nm, and by keeping the derivative carbazole layer constant at 100 nm the electro-luminescence (EL) changed from emissive exciton states to the mixture of emissive exciton and exciplex states. [3] For the former thicknesses no white light was obtained meanwhile for the later the EL spectra broadened due to the emission of exciplex states. Under this condition, the best-achieved CIE coordinate was (0.31,0.33) with a driving voltage of 8 V. To lower the driving voltage of the devices a thin film of LiF was added between the derivative of carbazol and cathode but the CIE coordinates changed. The best CIE coordinates for this case were (0.29, 0.34) and (0.32, 0.37) with driving voltage of about 6.5 V. Acknowledgments: CeMie-Sol/27 (Mexico) 207450 References [1] Timothy L Dawson, Society of Dyers and Colourists, Color. Technol., 126, 1–10 (2010), doi: 10.1111/j.1478-4408.2010.00220.x [2] G. M. Farinola, R. Ragni, Journal of Solid State Lighting, 2:9 (2015), doi: 10.1186/s40539-015-0028-7. [3] E. Angioni, et al, J. Mater. Chem. C, 2016, 4, 3851, doi: 10.1039/c6tc00750c.

Semi-Automatic Elemental Identification of Laser-Induced Breakdown Spectra Using Wavelength Similarity Coefficient

This work proposes a method to perform elemental identification on plasmas produced using the laser-induced breakdown spectroscopy (LIBS) technique. The method is based on the preservation of the relative relevance of the spectral line emission intensities, which is lost during the parametric correlation procedure, by the introduction of a similitude coefficient called wavelength similarity coefficient. Furthermore, it was shown that for identification purposes, a simplified plasma model is sufficient to predict adequately the relative emission intensities in LIBS plasmas. As a result, it is possible to automatically identify the species with high emission signals, while trace detection is also possible by relaxing search conditions, although manual refinement is still required.

Study of Archeological Mesoamerican Lapidary by Raman Spectroscopy: A Fast and Non-destructive Technique

The use of Raman spectroscopy for characterization of archeological objects has been widely used because it is a non-destructive technique. In this context, Raman spectroscopy is used to identify minerals in lapidary from Mexican pre-Columbian cultures

Rapid screening for quality control and adulteration in anti-diabetic drugs: quantitative and qualitative analysis by LIBS

This work describes an anti-diabetic medicament analysis by using LIBS. The emissions from elements present only in the active pharmaceutical ingredient and the Intensity ratios between them and the sample´s background allow a quality inspection.

Simple assembling of organic light emitting diodes for teaching purposes in undergraduate labs

Recibido el 21 de septiembre de 2007; aceptado el 15 de abril de 2008Electroluminescent organic molecules and polymers have emerged as advanced materials used to fabricate organic light-emitting diodes(OLEDs) whose unique technological features could revolutionize the industry of flat-panel displays. Although in many cases these novelorganic materials combine low cost and ease of processing, OLEDs fabrication for educational purposes has rarely been reported. In thiswork, we report a simple and inexpensive method to fabricate organic electroluminescent devices intended for educational purposes at theundergraduate level of physics, chemistry and material sciences. For ease of fabrication the cathode in the diode structure was formed byeither an alloy of Bi-Pb-Cd-Sn or by a Ga-In alloy in the liquid phase, or simply by silver paint, whereas we used ITO (Indium Tin Oxide)deposited on glass substrates as the anode. Substrates of flexible plastic were also used. The OLEDs were fabricated using the spin-coatingtechnique with solutions of the fluorescent materials Alq

Mobility in polymer composites doped with organic molecules using the time-of-flight technique

Charge transport phenomena in semiconducting doped polymers is very important due to their spread use in xerography, electroluminescent devices (OLEDs), photovoltaic cells and photorefractive systems. The carrier mobilities were determined by time-of-flight (TOF) measurements on indium-tin oxide/polymer composites/indium-tin oxide samples. Data are collected as a function of different external applied fields at various temperatures and are analyzed according to the disorder formalism.