2012 IEEE 18 th International Symposium for Design and Technology in Electronic Packaging (SIITME) 978-1-4673-4760-0/12/$31.00 ©2012 IEEE 85 25-28 Oct 2012, Alba Iulia, Romania Investigations on Organic Printed Resistors Based on PEDOT:PSS C. Ionescu, P. Svasta, A. Vasile University “Politehnica” of Bucharest, Center for Technological Electronics and Interconnection Techniques, UPB-CETTI, Bucharest, Romania ciprian.ionescu@cetti.ro D. Bonfert Fraunhofer Institution for Modular Solid State Technologies EMFT Munich, Germany Abstract— The emerging of printed and organic electronics has been proven as a major trend in the last years. The only major commercial issue is represented by the organic light emitting diodes (OLED). In the current paper will be shown the results of electrical investigations of organic resistors based on poly(3,4- ethylenedioxythiophene) doped with polystyrenesulfonic acid (PEDOT:PSS). The influence of the track width and of aspect ratio is also investigated. The samples are prepared by ink- jetting, using two subsequent depositions, one is the silver termination and the second one is the active resistor material. It is expected that the results offer a guidance for organic resistor dimensioning and resistor overall parameters (rated power, temperature coefficient of resistance-TCR). Index Terms— Organic Electronics, Organic Resistors, Conductive polymers, PEDOT:PSS. I. INTRODUCTION In order to build electronic modules, beside other components as organic photovoltaic cells (OPV), organic diodes, organic thin film transistors (OFET) it is necessary to use also passive components: resistors. capacitors or inductors. Due to the inherent limitations of temperature range and thermal stability, there are not many references on the subject of printed organic resistors. The use of the organic substance PEDOT:PSS, which formula derives from polythiophene, has been strongly analyzed in the last years [1] because of it’s good thermal behavior and mechanical properties. The application domains of this polymer include among others conducting layers in capacitors and resistive layers. Even though the organic conductive materials are intensively studied, we found a gap of publication in the direction of concrete circuit applications. The data sheets from manufacturers of PEDOT:PSS in most cases do not to mention very clear values about the performances of deposited layers, giving data only about the properties in liquid phase. More or less, even the requirements for organic devices integration are not clearly stated, having in mind the different substrates on which organic components are available: organic or inorganic, flexible or rigid as foil, glass, silicon, etc. The motivation of this paper resides in the need of finding design rules formulated in such a manner that a circuit engineer designer can use them and these can also be used in a real design task. II. THE PEDOT:PSS COMBINATION There are recently many reports of using PEDOT:PSS, a polythiophene derivative, in various domains [1]. The fields of applications of this polymer include: resistive layers, conducting layer in capacitors, antistatic coatings for cathode ray tubes, conductive tracks for printed wiring boards, hole injection layer in OLEDs, transparent conductor in various displays, conductor and/or semiconductor layer in OFETs, active layer in electrochromic displays. Depending on the content of PSS in the complex polymer matrix, the conductivity can be varied from 10 –5 S cm –1 for a ratio PEDOT/PSS 1 : 20 up to 1 S cm –1 for a ratio 1 : 2.5. The chemical formula of PEDOT:PSS is presented in fig 1. Fig. 1. Chemical structure of Poly(3,4-ethylenedioxythiophene)- poly(styrenesulfonate).