We report on the preparation and performance enhancement of n-type low-voltage organic field effect transistors (FETs) based on cross-linked poly(vinyl alcohol) (cr-PVA) as gate dielectric and C60 fullerene as channel semiconductor. Transistors were prepared using bottom-gate top-contact geometry and exhibited field-effect mobility (µFET) of 0.18 cm2V-1s-1. Treatment of the gate dielectric surface with an anionic surfactant, sodium dodecyl sulfate (SDS), passivates the positively charged defects present on the surface of cr-PVA, hence resulting in overall transistor performance improvement with an increase in µFET to 1.05 cm2V-1s-1 and additional significant improvements in dielectric capacitance, transistor on/off current ratio and transconductance.

In this work we report efficiency measurements on light-emitting diodes with electrochemically synthesized sulfonated polyaniline as hole transport layer. The anode used in our devices is fluorine-doped tin oxide, the blocking layer is electrochemically synthesized poly(9,9-dioctyl-1,4-fluorenylenevinylene) and the electron transporting material and emitter is tris-(8-hydroxyquinoline) aluminum. Sulfonated polyaniline based devices presented efficiency of 0.79 cd/A.

We investigate the electronic characteristics and the absorption spectra of poly(3-octylthiophene), POT, films grown by electrochemical methods onto Au substrates. We discuss the results considering the morphological factor. POT films thickness can be controlled by current density in the electropolymerization process. The film roughness depends on the thickness, being about 12% of film thickness. The samples for electrical measurements were made in sandwich structure, Au/POT/metal (metal: Ni, Al). Analyzing current-voltage data we were able to estimate the positive charge carrier mobility (5 x 10-4 cm² V-1 s-1) and the potential barrier height in the metal/polymer interfaces (0.1 eV for Au/POT and Ni/POT and 0.85 eV for Al/POT).

Neste artigo é apresentada uma introdução aos polímeros conjugados, evidenciando-os como materiais portadores de um conjunto de propriedades que os torna altamente promissores para o uso em diodos emissores de luz e fotodetectores orgânicos. Inicialmente faz-se uma breve descrição das características físicas dessa classe de polímeros, justificando sua potencialidade na construção de dispositivos. Em seguida, apresenta-se um breve histórico do desenvolvimento de dispositivos orgânicos e uma descrição do estágio de desenvolvimento atingido. As dificuldades inerentes à construção de dispositivos que utilizam polímeros conjugados são discutidas, ressaltando os problemas a serem solucionados para que se tornem mais eficientes.

In this paper we present an introduction to conjugated polymers as materials with a set of promising properties for applications in organic light emitting diodes and in organic photodetectors. We start with a short description of the physical properties of conjugated polymers, emphasising its potential for device construction. The difficulties inherent to the construction of conjugated polymer-based devices are discussed and the problems that limit device efficiency are listed.