A series of new conjugated oligothiophenes for organic electronics

Thiophene oligomers and polymers can be found in a huge number of materials with applications in the field of Organic Electronics. Chemical and electrochemical syntheses along with electrochemical studies and complete characterization of a series of new conjugated oligothiophene derivatives are reported. Two different molecular architectures, D-A (donor-acceptor) and A-D-A (acceptor-donor-acceptor), were taken into account. The results from voltammetric experiments and optical studies confirm the close relationship between the structure of these compounds and their electrochemical behaviour. This series of oligothiophenes shows low bandgaps, a mandatory requirement for their use in Organic Electronics, and, clearly, they are promising candidates for future synthetic studies in order to modify their optical and electrochemical properties to achieve better performances as organic semiconductors

An insight into the reactivity of the electrogenerated radical cation of caffeine

Controlled potential electrolyses of caffeine (CAF) were carried out at a Pt electrode in undried acetonitrile (ACN) and ACN-H2O and the products of the anodic oxidation were analyzed by HPLC-PDA-ESI-MS/MS. A higher current efficiency occurred in ACN-H2O, but an analogous chromatographic outline was found in both media, evidencing a reactive pathway of the electrogenerated radical cation CAF•+ with water, added or in trace, as nucleophile. No dimeric forms were evidenced, excluding any coupling reactions. Neither was 1,3,7-trimethyluric acid found, reported in the literature as the main oxidative route for CAF in water. Four main chromatographic peaks were evidenced, assigned to four proposed structures on the base of chromatographic and spectral data: a 4,5-diol derivative and an oxazolidin-2-one derivative were assigned as principal oxidation products, supporting a mechanism proposed in a previous work for the primary anodic oxidation of the methylxanthines olefinic C4 = C 5 bond. Two highly polar degradation products were also tentatively assigned, that seemed generating along two different pathways, one opening the imidazolic moiety and another one opening the purinic one

Development of an electrochemiluminescence-based lab-on-chip using thin/thick film technologies

This work reports on design and fabrication of a compact lab-on-chip system, based on detection of electrochemiluminescence (ECL) through thin film sensors. The proposed system couples an optoelectronic platform to a disposable microfluidic chip. The optoelectronic platform includes amorphous silicon photosensors for detection of ECL, while the microfluidic chip contains the ECL electrodes and the biological solutions to be analyzed. Optoelectronic characterization of photosensors and preliminary test on the ECL electrodes by cycling voltammetry show the suitability of these devices for the achievement of low-noise and high sensitive system