Characteristics Improvement of PEDOT:PSS Transparent Conductive Film Prepared by Ink-Jet Printing

Atsushi Nitta,Kohei Miyata,Kazuya Kawahara

doi:10.4236/ampc.2016.68024

Abstract

Recently, a high-performance and low-priced transparent conductive film has been expected to be developed because flexible devices produced using organic materials have been actively studied. An indium tin oxide (ITO) thin film, which has been generally used as a material for a transparent conductive film, has problems, such as fragility to bending stress and depletion of the resource. The present study used poly(3, 4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS), an organic electroconductive material, and examined the improvement in the resistance value and visible light transmittance of a transparent conductive film produced using the ink-jet method. In previous studies, we reported that, to improve the resistance value and visible light transmittance of a thin film, it was effective to clean the film substrate with ultraviolet/ozone (UV/O3) treatment, anneal the film after it was deposited on the substance, and dip the annealed film into a polar solvent. Focusing on the thin film processing between printing operations, the present study improved resistance value and visible light transmittance by examining both the application methods of a polar solvent and the annealing time between printing operations. As a result, the resistance value and visible light transmittance of a PEDOT:PSS thin film were 390.4 Ω and 86.6%, respectively. This film was obtained by applying a polar solvent and performing annealing for 30 min between printing operations. The printing was performed three times.

Highlights

Studies on flexible devices produced using organic materials and carbon nanotubes (CNTs) have been briskly conducted [1]-[4]
The visible light transmittance was higher in a thin film obtained by applying the polar solvent to each layer than in a thin film obtained by performing the dipping treatment
To improve the characteristics of a PEDOT:PSS transparent conductive film produced using an ink-jet printer, the present study examined a method in which a polar solvent was applied to each layer and the effects of the annealing time between printing operations on the resistance value and visible light transmittance of the produced thin film

Summary

Introduction

Studies on flexible devices produced using organic materials and carbon nanotubes (CNTs) have been briskly conducted [1]-[4]. Ohno et al of Nagoya University in Japan and a research team of Aalto University in Finland developed an all-carbon integrated circuit composed of transistors and wires, which were made of only CNTs, for the first time in the world due to the optimization of CNT thin film-forming technologies [5] Devices such as electroluminescence displays, thin-film solar cells, and transistors produced using organic materials have been positively developed [6]-[11]. Because an ITO thin film shows fragility to bending stress, this film is not suitable for flexible devices To solve these problems, various materials such as organic materials, metallic nanoparticles, CNTs, and oxide-based materials have been studied [16]-[21]. We examined the effects of both the application of a polar solvent on the film each time after a layer was printed, and the annealing time between printing operations on the improved characteristics of a PEDOT:PSS thin film

Experimental

Results and Discussion

Examination of Treatment Methods Using the Polar Solvent

Examination of Annealing Time between Printing Operations

Conclusions