Browsing by Author "González Guzmán, Alexis Fabián"

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    Evaluation of thermal evaporation as a deposition method for vacuum-processed polymer-based organic photovoltaic devices
    (2025) González Guzmán, Alexis Fabián; Sobarzo Aucal, Patricio Antonio; Saldías Barros, César Antonio; Terraza Inostroza, Claudio; Ángel Figueroa, Felipe Alfonso
    In this study, we aimed to evaluate the evaporating fractions of a polymeric material by thermal evaporation to scale up polymer-based organic photovoltaic (OPV) devices. Due to its high thermal stability and suitable optoelectronic properties, we used a poly(azomethine)-based material (PAZ2ThA2) as the donor layer. The control and reproducibility of our methodology were confirmed through two specific analyses: size exclusion chromatography, which allowed us to separate and measure the size of the deposited material, and UV–visible absorption spectroscopy, which provided information about the light absorption of the evaporated fractions. Our deposition rates reached a maximum of 1.4 Å·s−1. We fabricated bilayer OPV devices to evaluate the thickness dependence of the deposited fractions and achieved a maximum short-circuit current density of 1.60 mA·cm−2 at 9 nm thickness. These results confirm the feasibility of obtaining reproducible vacuum-processed polymer-based OPV devices, a significant step toward their scalability.
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    Thiophene- and bithiophene-based π-conjugated Schiff base oligomers containing binaphthalene moieties in the backbone. Properties and computational simulations
    (Royal Sociaty of Chemistry, 2024) González Guzmán, Alexis Fabián; Mariman Marchant, Andrea Paz; Hauyón Sepúlveda, René Alejandro; Pavéz Lizana, Danitza Belén; Saldías Barros, César Antonio; Schott Verdugo, Eduardo; Zarate, Ximena; García Paredes, Luis Enrique; Gonzalez-Henriquez, Carmen M.; Jessop, Ignacio A.; Tundidor Camba, Alain; Sobarzo Aucal, Patricio Antonio; Terraza Inostroza, Claudio
    New pi-conjugated Schiff base oligomers (o-AZdAN1Th and o-AZdAN2Th) based on a binaphthalene core and containing thiophene or bithiophene units in their backbone were synthesized from the reaction between [1,1 '-binaphthalene]-4,4 '-diamine with thiophene-2,5-dicarbaldehyde and [2,2 '-bithiophene]-5,5 '-dicarbaldehyde by a high-temperature polycondensation method. These new materials were slightly soluble in non-protic polar solvents, such as chloroform and dichloromethane. From GPC analysis of the CHCl3-soluble fraction, o-AZdAN1Th was found to be a tetramer, whereas o-AZdAN2Th was a trimer with 1.4 kDa and 1.3 kDa average molecular weight (Mn), respectively. Both samples exhibited high thermal stability with T5% values of 452 degrees C and 456 degrees C and relatively high Tg values of 346 degrees C and 384 degrees C, for o-AZdAN1Th and o-AZdAN2Th, respectively. The samples showed absorptions in the deep-blue (o-AZdAN1Th) and blue (o-AZdAN2Th) regions of the visible spectrum, and emission responses at 387 nm and 447 nm, respectively, with moderate Stokes shifts (77-95 nm). Their optical and electronic properties were similar to those described for thiophene-based materials, with optical bandgap values close to 2.4 eV. HOMO energy values of -5.98 and -5.95 eV and LUMO energy values of -3.87 eV and -3.84 eV were obtained for o-AZdAN1Th and o-AZdAN2Th, respectively. Theoretical DFT and TD-DFT calculations were used to compare the effect of increasing thiophene units along the backbone for the real and also theoretical o-AZdANxTh samples (x = 3 and 4 thiophene units). According to our study, these two new thiophene-based can be proposed for optoelectronic applications., Schiff base oligomers based on a binaphthalene core were synthesized from [1,1 '-binaphthalene]-4,4 '-diamine with thiophene-2,5-dicarbaldehyde and [2,2 '-bithiophene]-5,5 '-dicarbaldehyde by a high-temperature polycondensation method.