Photoluminescence (PL) and electroluminescence (EL) emissions from blended films composed by Poly[2-(2′,5′-bis(2′-ethyl-hexyloxy)phenyl)-1,4-phenylenevinylene] (BEHP-PPV) and poly(3-hexylthiophene) (P3HT) conjugated polymers are investigated. A PL broad emission spectrum within the visible range was obtained for the BEHP-PPV/P3HT blends. The electroluminescence (EL) spectra of light emission devices fabricated with the blended films with 50% and 25% relative concentration of P3HT present a similar broad emission but shifted to higher wavelengths with increasing applied bias. This tuning capacity was interpreted as due to a change in the effective gap of the blended system caused by the redistribution of injected carriers in the BEHP-PPV/P3HT interfaces of the blend under bias.

In this work; resistive moisture sensors were obtained by dip coating sulfonated polycarbonate (SPC) onto silver interdigitated electrodes. Commercial polycarbonate was sulfonated with acetyl sulphate at two different sulfonation degrees corresponding to 9.0 and 18.0 mole %. Impedance spectroscopy was used to investigate the humidity sensing properties at controlled relative humidity (RH%) environments generated from standard saline solutions in the range of 11–90 RH%. For the highest sulfonated sample; in the RH% range investigated (11 to 90%); the sensor impedance changed from 4.7 MΩ to 18 kΩ. Humidity sensors made from sulfonated polycarbonate showed exponential decay behavior of the impedance at constant frequency with the environmental relative humidity. Sample 9SPC presented dielectric relaxation response for environmental humidity between 58 and 90 RH% while sample 18SPC presented dielectric relaxation response for the entire measured range between 11 and 90 RH%. Sulfonated polycarbonate could be a promising material for the fabrication of simple and cheap humidity-sensing sensors for the assessment of relative humidity of the surrounding environment, as suggested by experimental results.