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

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.

To Investigate the Effect of Using Ethanol Containing Wipes in Collecting Blood for the Measurement of Alcohol Concentration

This study was aimed to establish whether the skin preparation using ethanol-containing skin antiseptics causes ethanol contamination through blood collection. Venous blood was collected from 40 healthy volunteers according to the national guidelines for blood sampling, with four sequential procedures as follows: 1) collecting blood immediately (within 5 seconds) after cleaning the skin with an individually packaged type of ethanol-containing wipe, 2) collecting blood 1 minute after cleaning the skin with an individually packaged type of ethanol-containing wipe, 3) collecting immediately (within 5 seconds) after cleaning the skin with a traditional cleaning method (thoroughly ethanol-impregnated wipe, and 4) collecting 1 minute after cleaning the skin with a traditional cleaning method. Each sequential procedure was performed with and without the ethanol-containing wipe used for skin cleaning on the puncture site on their right and left arms at the time the needle was withdrawn, respectively. The collected specimens were subjected to the determination of ethanol by using headspace gas chromatography-mass spectrometry. In every 80 blood specimens obtained from 40 participants, ethanol was undetectable (<0.001 mg/mL). This study demonstrates that disinfection using ethanol-containing skin antiseptics is unlikely to cause ethanol contamination through blood collection regardless of skin preparation technique according to the guidelines for blood sampling. This may have implications in forensic science.

Preparation of PDOT:PSS Transparent Conductive Film Using Ink-Jet Printing

Flexible devices produced using organic materials have attracted the attention of many researchers. Important components of these flexible devices include transparent electrodes, which transmit visible light and possess conductivity. The present study improved the characteristics of a transparent conductive film that was made of poly(3, 4 ethylenedioxythiophene):poly(styrenesul-fonate) (PEDOT:PSS), an organic conductive material, and that had been prepared using ink-jet printing. To improve the resistance value and visible light transmittance of the film, the film substrate was first cleaned with ultraviolet/ozone treatment, and then the film was annealed after it was deposited on the substrate and dipped into a polar solvent. Consequently, the resistance value of the thin film decreased. However, the surface state of the film changed according to the treatment method and affected its visible light transmittance. Thus, the surface state of the film substrate, the annealing temperature after film deposition, and the dipping treatment with a polar solvent influenced the characteristics of a thin film.

The Polar Solvent Application Method for Organic Transparent Conductive Film Produced by an Inkjet Printing Method

In recent years, flexible electronic devices have attracted much attention. Accordingly, flexible transparent conductive films are being researched actively. The commonly used indium tin oxide (ITO) transparent conductive film has limited flexibility. Therefore, we focused on poly(3,4-ethylenedioxythio- phene)/poly(styrenesulfonate)(PEDOT:PSS) as a substitute material for ITO and are engaged in producing flexible transparent conductive film using inkjet printers. To improve the characteristics of the transparent conductive film produced by inkjet printing, based on prior research, we found that cleaning the film substrate with ultraviolet/ozone (UV/O3) and post-deposition annealing and treatment using polar solvents are effective for thin films. In this study, we examined the method of applying the polar solvent. As a result, we were able to improve the homogeneity of the thin film surface by applying the polar solvent to each thin film lamination layer. The resulting characteristics obtained for a three-layer printed PEDOT:PSS thin film with polar solvent coating were resistivity of 1.49 × 10-3 Ω·cm and transmittance of 84.6%. However, we found that the surface condition changed depending on the processing method, affecting the rate of visible light transmittance.

Examination of Treatment Methods for a PEDOT:PSS Transparent Conductive Film Produced Using an Inkjet Method

Flexible devices manufactured using printed electronics have attracted the attention of many researchers. A high-performance transparent conductive film exhibiting high flexibility and elasticity is expected to be developed because of its need for the creation of flexible devices. An indium tin oxide (ITO) thin film, which has generally been used, has weaknesses such as fragility to bending stress and depletion of the resource. This study focused on poly (3, 4-ethy-lenedioxythiophene)/poly (styrenesulfonate) (PEDOT:PSS), a conductive polymer material, and examined improvement in the resistivity and transmittance of the transparent conductive film produced using an inkjet method. The present study improved the electrical and optical characteristics of the thin film by examining the annealing temperature between printing operations and the application method of a polar solvent. As a result, the resistivity and transmittance of a PEDOT:PSS thin film were 1.49 × 10-3 Ω&middot;cm and 89.2%, respectively. This film was obtained by annealing at 90&deg;C for 30 min and applying a polar solvent, using an inkjet printer, between printing operations. The printing was performed three times.