ISSN 1923-8460[PRINT] ISSN 1923-8479[ONLINE] www.cscanada.net www.cscanada.org Energy Science and Technology Vol. 4, No. 2, 2012, pp. 6-11 DOI:10.3968/j.est.1923847920120402.528 6 Copyright © Canadian Research & Development Center of Sciences and Cultures A Versatile Technique for the Fabrication of PEDOT: PSS Films for Organic Solar Cells Ashwith K. Chilvery [a],* ; Ashok K. Batra [a] ; Padmaja Guggilla [a] ; R. B. Lal [a] ; Raja Surabhi [a] [a] Department of Physics, Chemistry and Mathematics, Alabama A&M University, P.O.Box 1268, Normal, USA. * Corresponding author. Received 22 August 2012; accepted 1 November 2012 Abstract Organic solar cells hold the potential of low-cost production as compared to inorganic solar cells, as well as the increase in effciency. To realize these possibilities, the key is to fabricate most of the functional flms in requisite structures via ambient solution-processed techniques. The PEDOT: PSS flms, which are commonly used as an anode layer in organic electronic devices, were deposited on large-area ITO glass substrates under optimized conditions. The spin, spray, brush and brush+spray-coating techniques were utilized to examine their suitability in the fabrication of organic solar cells (OSCs). The flms were characterized for their morphology, molecular structure, optical and electrical properties and results are compared with the existing data. A smooth and thin flms of PEDOT: PSS were obtained by “Spray+Brush” coating method with attractive sheet-conductivity having potential in fabricating OSCs with different architectures. Key words: Organic solar cells; PEDOT: PSS flms; Solution-processed techniques Chilvery, A. K., Batra, A. K., Guggilla, P., Lal, R. B., & Surabhi, R. (2012). A Versatile Technique for the Fabrication of PEDOT: PSS Films for Organic Solar Cells. Energy Science and Technology, 4(2), 6-11. Available from: URL: http://www.cscanada.net/index. php/est/article/view/10.3968/j.est.1923847920120402.528 DOI: http://dx.doi.org/10.3968/j.est.1923847920120402.528 INTRODUCTION The Organic Photovoltaics (OPVs) has seen unprecedented growth during the past decade because of its lower-cost, durability, flexibility, and adaptable substitute for rigid silicon solar cells (Vasselinka, Rudolf, & Adolf, 2009; Zheng & Xue, 2010; Liang & Yu, 2010). Silicon-based solar cells fabrication processes are expensive and complicated involving clean rooms, lithography, and vacuum chambers. Efforts have been made, in the recent past, to improve organic solar cell performance using new materials, novel architectures, and new techniques for mass production. Solution processed techniques like ink-jet printing; spin coating, spray depositing etc, hold greater potential and prove cost- effectiveness in fabricating the OPV’s (Na et al., 2010; Green et al., 2008; Ouyang et al., 2004). High effciencies can be gained, by performing the fabrication steps inside a nitrogen glove box. Additionally, the widely used OPVs geometry utilizes aluminium or calcium metal contacts. Since, the performance of the films deteriorate over time, the cells cannot be operated without encapsulation. In this geometry, it is possible to use noble metals at top electrodes and avoid performance losses due to top contact oxidation. Other approach is the insertion of a thin layer of poly (3, 4-ethylenedioxythiophene): poly(styrene- sulfonate), hereafter referred to as PEDOT: PSS, underneath the top contact. The PEDOT: PSS layer can lower or raise the work functions of the cathode or anode, or enhance the cohesion, and thus lower the interfacial series resistance. Moreover, it is commonly used in non- inverting organic solar cells to enhance the hole-collection and thus improve the efficiency of organic solar cells (Vasselinka et al., 2009). Thus, importance of PEDOT: PSS flm warrants fabrication of low cost OPV’s via low low cost solution processing techniques such as spray and brush coating. In the present study, several flm-depositing techniques of PEDOT: PSS on ITO glass substrates, namely spin- coating, spray-coating, brush-painting and spray+brush (both together) were explored. It was demonstrated that coating technique "Spray+Brush", without the use of special machine such as a spin-coater, is a viable alternative.