A facile way to pattern PEDOT:PSS film as an electrode for organic devices

Abstract

We report a facile and high resolution patterning method for conductive polymer films as transparent electrodes for organic devices on various substrates. The reliable pattern of PEDOT:PSS film is demonstrated by selective oxygen plasma etching via a defined copper (Cu) protection layer deposited by thermal evaporation. The overcoated Cu layer is removed by a wet etching process without damage to the underlying PEDOT:PSS layer. The minimum patterning feature size is determined by the resolution of the mask for Cu deposition and has shown to reach twenties of micro-meters. The patterned PEDOT:PSS film is successfully applied as source-drain electrodes for the organic field effect transistors (OFETs), and as a transparent anode in organic photodiodes (OPDs). Performance of flexible PEDOT:PSS-based OPDs exceeds a conventional flexible IZO-anode OPDs (6.6 mA/W vs. 1.4 mA/W, respectively). The contact resistance of PEDOT:PSS electrodes in OFETs is found to be 10 times lower (9.8 × 102 Ω cm), than that for Au counterparts. The hole mobility was 0.29 cm2/V s for both electrode materials and used DPPT-TT semiconductor polymer.