RESUMO
The interface between the semiconductor and the dielectric layer plays a crucial role in organic field-effect transistors (OFETs) because it is at the interface that charge carriers are accumulated and transported. In this study, four zwitterionic benzoquinonemonoimine dyes featuring alkyl and aryl N-substituents were used to cover the dielectric layers in OFET structures. The best interlayer material, containing aliphatic side groups, increased charge carrier mobility in the measured systems. This improvement can be explained by the reduction in the number of the charge carrier trapping sites at the dielectric active layer interface from 1014 eV-1 cm-2 to 2 × 1013 eV-1 cm-2. The density of the traps was one order of magnitude lower compared to the unmodified transistors. This resulted in an increase in charge carrier mobility in the tested poly [2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)thieno [3,2-b]thiophene)] (DPPDTT)-based transistors to 5.4 × 10-1 cm2 V-1 s-1.
RESUMO
The transamination of oxoaminobenzoquinonemonoimine (BQI derivatives), an unconventional zwitterionic quinone, allows isolation of a series of compounds featuring electron-donating aryl auxochromes. The substitution has a very strong impact on the electrochemical and optical features, which is rationalized by theoretical calculations. Protonation and alkylation of the BQIs toward the corresponding cations lead to surprising red-shifts of the absorption, especially in the instance of the most electron-rich dyes that exhibit panchromatic absorption spanning up to the near-infrared (NIR) region, a remarkable achievement for such small molecules.
