Inkjet printing of organic field-effect transistors using biocellulose derivative materials
Pereira, A. T. P.
; Pecoraro, E.
; Ferreira, C. S. R. F.
Inkjet printing of organic field-effect transistors using biocellulose derivative materials, Proc Encontro Nacional da SPQ, Braga, Portugal, Vol. n.a., pp. n.a. - n.a., July, 2011.
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Biocellulose (BC) is a pure form of cellulose and was naturally produced from the bacteria Glucanacetobacter xylinus. BC based materials are being studied for applications in organic electronics, both as substrate and as dielectric. The electric properties of BC compare well with the commonly used substrate materials poly(ethylene naphtalate) (PEN) and poly(ethylene terephtalate) (PET). BC has a low coefficient of thermal expansion (0.1-6 ppm/°C), it is stable upon 260 °C and its dielectric constant is in the range of k = 1.6 − 1.9. BC has also the advantages of being renewable and biodegradable.
Inkjet printing of electronics permits low cost and large area fabrication and it is compatible with flexible substrates, such as BC. Inkjet printing is being used to print transistors arrays with small dimensions and high yield. In this work inkjet printing of organic field-effect transistors (OFET) using BC based materials is being developed. The OFETs are fabricated using inkjet-printed silver gate and source-drain electrodes. A chitosan-bacterial cellulose composite deposited by spin-coating, is used as dielectric. Inkjet-printed poly(9,9-dioctylfuorene-co-bithiophene) (F8T2) is used as semiconductor. A scheme of the structure of the fabricated OFET is shown in Fig. 1. All the fabrication processes were performed using a maximum temperature of 150 °C at ambient atmosphere. The performance and stability of inkjet fabricated OFETs are compared with those of similar OFETs fabricated using traditional fabrication methods, namely, thermal evaporation of electrodes and spin-coating of the semiconductor .