Marisol Güizado-Rodríguez

Third-Order Nonlinear Optical Behavior of Novel Polythiophene Derivatives Functionalized with Disperse Red 19 Chromophore

Two copolymers of 3-alkylthiophene (alkyl = hexyl, octyl) and a thiophene functionalized with disperse red 19 (TDR19) as chromophore side chain were synthesized by oxidative polymerization. The synthetic procedure was easy to perform, cost-effective, and highly versatile. The molecular structure, molecular weight distribution, film morphology, and optical and thermal properties of these polythiophene derivatives were determined by NMR, FT-IR, UV-Vis GPC, DSC-TGA, and AFM. The third-order nonlinear optical response of these materials was performed with nanosecond and femtosecond laser pulses by using the third-harmonic generation (THG) and Z-scan techniques at infrared wavelengths of 1300 and 800 nm, respectively. From these experiments it was observed that although the TRD19 incorporation into the side chain of the copolymers was lower than 5%, it was sufficient to increase their nonlinear response in solid state. For instance, the third-order nonlinear electric susceptibility () of solid thin films made of these copolymers exhibited an increment of nearly 60% when TDR19 incorporation increased from 3% to 5%. In solution, the copolymers exhibited similar two-photon absorption cross sections with a maximum value of 8545 GM and 233 GM (1 GM = 10−50 cm4 s) per repeated monomeric unit.

Synthesis of 2-(Thiophen-3-yl)vinylphosphonic Acid

Abstract A simple and efficient synthesis of 2-(thiophen-3-yl)vinylphosphonic acid has been developed. The title compound is obtained in 70% yield by addition of thiophene-3-carbaldehyde to lithium diethyl methylenephosphonate, followed by dehydration and hydrolysis. 1H, 13C, and 31P NMR spectra are presented for each of the intermediates.

Stabilization of Silver Nanoparticles with a Dithiocarbamate Ligand and Formation of Nanocomposites by Combination with Polythiophene Derivative Nanoparticles

Spherical morphology for silver nanoparticles (Ag NPs) stabilized with dithiocarbamate (DTC) by reducing silver nitrate with sodium borohydride was obtained, while the addition of sodium citrate and hydrogen peroxide allowed the formation of silver nanotriangles (Ag NTs). Solutions of bright yellow and blue colors characteristic of both morphologies were observed. UV-vis optical analysis of NPs stabilized with DTC showed a plasmonic absorption band at 393 nm characteristic for spherical morphology, while two bands were observed at 332 nm and 762 nm, and a shoulder around 500 nm for the triangular morphology; with these spectra each morphology was confirmed. In these spectra an absorption band between 250 and 260 nm confirms the presence of DTC ligand. The stability of the NPs was achieved using an 8.69 × 10-3 mM solution of 4-(ethylaminodithiocarbamate) methylpyridine di-n-butyltin (IV) through a transmetallation reaction. Silver nanoparticles (Ag NPs) with spherical morphology of average diameter of 12.7 ± 1.2 nm and triangular morphology with 28.9 ± 0.8 nm for each side of the triangles were analyzed by high resolution scanning electron microscopy (HR-SEM). UV-vis spectra also showed the stability of NPs with DTC for more than three months. A copolymer derived of 3-hexylthiophene with (E)-2-(ethyl(4-((4-nitrophenyl) diazenyl) phenyl) amino) ethyl 2-(thiophen-3-yl) acetate (PA) was tested to get polymer NPs by reprecipitation method using THF/water systems. PA Polymer NPs having average diameter of 9.0 ± 1.7 nm were found. By quick and easy procedure, the formation of nanocomposite (NC) of spherical Ag NPs and PA polymer NPs was reached. This NC could be used as imaging agent, electrochemical biosensor, and photonic and optoelectronic device materials.

Physicochemical and Luminescent Properties of Copolymers Composed of Three Monomers: Polythiophenes Based on 3-Hexylthiophene and 3,4-Ethylenedioxythiophene

The chemical synthesis and physicochemical and luminescent characterizations of polymers based on 3-HT, EDOT, and 2,2′-(9,9-dioctyl-9H-fluorene-2,7-diyl) bisthiophene (fluorene) or (E)-2-(ethyl(4-((4-nitrophenyl)diazenyl)phenyl)amino)ethyl 2-(thiophen-3-yl)acetate (TDR1) are reported. The fluorene unit was bound to the conjugate backbone, while the Disperse Red 1 (DR1) chromophore was present as a pendant group. Characterizations by 1H NMR, FT-IR, DSC-TGA, GPC, UV-vis, cyclic voltammetry, fluorescence quantum yield, excited state lifetime, and two-photon absorption cross-section were carried out. These polymers combined the physicochemical properties of EDOT and 3-HT, such as high electron density, high charge mobility, low oxidation potential, and good processability. The optical properties of these copolymers were highly dependent on the presence of EDOT, the molecular weight, and the regioregularity rather than the presence of the third component (fluorene or TDR1). The good nonlinear absorption and luminescent properties exhibited by these copolymers were exploited to fabricate nanoparticles used as fluorescent tags for the imaging of microstructures.

Photophysical Study of Polymer-Based Solar Cells with an Organo-Boron Molecule in the Active Layer

Our group previously reported the synthesis of four polythiophene derivatives (P1–P4) used for solar cells. The cells were prepared under room conditions by spin coating, leading to low efficiencies. However, after the addition of 6-nitro-3-(E)-3-(4-dimethylaminophenyl)allylidene)-2,3-dihydrobenzo[d]-[1,3,2] oxazaborole (M1) to their active layers, the efficiencies of the cells showed approximately a two-fold improvement. In this paper, we study this enhancement mechanism by performing ultrafast transient absorption (TA) experiments on the active layer of the different cells. Our samples consisted of thin films of a mixture of PC61BM with the polythiophenes derivatives P1–P4. We prepared two versions of each sample, one including the molecule M1 and another without it. The TA data suggests that the efficiency improvement after addition of M1 is due not only to an extended absorption spectrum towards the infrared region causing a larger population of excitons but also to the possible creation of additional channels for transport of excitons and/or electrons to the PC61BM interface.

Crystal structure of 1,3-di­cyclo­hexyl-1-[3-(pyren-1-yl)prop­anoyl]urea

In the title compound, C33H38N2O2, each of the cyclohexyl rings adopts a chair conformation. The two planes involving carbonyl groups, C—(C=O)—N and N—(C=O)—N, are oriented at a dihedral angle of 62.28 (10)°. In the crystal, two neighboring molecules are linked by a pair of N—H⋯O interactions, generating an inversion dimer. The dimers are interconnected by C—H⋯O hydrogen bonds into a supramolecular chain along the a-axis direction.