Lead sulfide (PbS)
nanoparticles were synthesized by chemical methods
with different sizes and different capping ligands (oleic acid, myristic
acid, and hexanoic acid), avoiding ligand exchange procedures, to
study the effect of characteristics of the capping ligands on their
energy levels and band gap values. Experimental results (UV–vis–NIR,
Fourier transform infrared, and Raman spectroscopies, cyclic voltammetry,
transmission electron microscopy, and electron energy loss spectroscopy)
showed a marked influence of the capping ligand nature on the electro-optical
properties of PbS nanoparticles with a very similar size. Differences
were observed in the atomistic arrangement on the nanoparticle surface
and phonon vibrations with the different capping ligands. These observations
suggest that the electro-optical properties of PbS nanoparticles are
not only determined by their size, through quantum confinement effects,
but also strongly affected by the atomistic arrangement on the nanoparticle
surface, which is determined by the capping ligand nature.
The facile functionalization of the fluorene scaffold at the 2,7-positions was utilized to provide access to two soluble carbazole-π-carbazole derivatives CFC-H1 and CFC-F1 featuring fully hydrogenated and polyfluorinated alkyl chains at the 9position of the fluorene π-bridging unit, respectively. The optical and electrochemical properties of the new dicarbazoles were investigated. Their electrochemical polymerization over Pt and indium tin oxide electrodes allowed the generation of electroactive polymeric films, whose physicochemical characteristics were strongly dependent on the kind of alkyl chain present on the fluorene bridge. In particular, the electropolymerization of the polyfluorinated monomer allowed the fabrication of thin films with good electrical conductivity, reversible electrochemical processes, good electrochromic properties, and enhanced water repellency with respect to its nonfluorinated analogue.
The design and synthesis of novel dendrimeric structures derived from a pyrene core with substituted triphenylamine and carbazole periphery demonstrated how molecular engineering allowed the fine tuning of the electrogenerated chemiluminiscence (ECL) properties. These two compound (Py-CBZ and Py-TPA) in comparison with the parent structures (Py and Py-Core) showed better chemical stability and anti-aggregation capability. At the same time, the photophysical ( Abs λ max , E 00 , FL λ max , FL ), photochemical (oxygen quenching), electrochemical (redox potentials) and optoelectronic (HOMO-LUMO gap and their energy position) properties were modulated, resulting in obtaining two highly ECL emitting molecular structures (Py-CBZ and Py-TPA). This study showed that functionalization of organic dyes with redox moieties (with the proper linker and position) improved the radical stability and also, modulated the optoelectronic properties with the concomitant enhancement of the ECL performance and their potential use in applications such as organic light-emitting devices.
The use of glyphosate (GlyP) in agriculture has caused environmental and health concerns in modern society. Even today, its quantification remains an analytical challenge. Therefore, the development of analytical methods is required that allows an increase in sample throughput and cost-savings. This study presents a study of the electrochemiluminescence (ECL) behaviour of the GlyP/Ru(bpy) 3 2+ system on gold electrodes modified with self-assembled monolayers (SAM). The ECL response was analysed on three different electrode surfaces, bare gold and alkyl-thiol monolayers with ionizable (-COOH) and non-ionizable (-CH 3 ) terminal group. It was found that the ECL signal of the GlyP/Ru(bpy) 3 2+ system was improved by the modification of the electrodes reaching a limit of quantification (LOQ) of 6.42 mM when the SAM contained a carboxylic end-group. In addition, the effect of the electrodes modification on the ECL behaviour is discussed. The results obtained and the calculated analytical parameters show the potential of the proposed method to determine GlyP.
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