Effect of organic solvents on the properties of DWCNT/PEDOT:PSS transparent conductive films

In this study, the transparent conductive films (TCFs) based on double-walled carbon nanotube (DWCNT) and poly (3,4-ethylene dioxythiophene): poly (styrene sulfonate) (PEDOT:PSS) were fabricated on glass substrates by spin coating method at room temperature. The DWCNTs with COOH functional group were dispersed in three different organic solvents including acetone, isopropanol and ethanol. The effect of organic solvents on the surface morphology, optical transmittance and sheet resistance of the DWCNT/PEDOT: PSS films were characterized by using the field emission scanning electron microscopy (FESEM), UV-vis spectroscopy and four-point probe technique. The results showed that the DWCNT/PEDOT: PSS films with the DWCNT-COOH dispersed in ethanol solvent had high transmittance of 80.3% at the 550 nm wavelength, low sheet resistance of 14.5 Omega/square and figure of merit of 7.69 x 10(-3) Omega(-1). To evaluate the potential working performance in the photovoltaic devices, the prepared TCFs were used as a top electrode of the simple solar cell device based organic/inorganic (PEDOT: PSS/n-Si) hybrid structure. The highest power conversation efficiency (PCE) was obtained to be 5.35% for a cell using ethanol, which was about 2.3 and 1.4 times higher than that of cells using IPA and acetone as dispersion solvents for DWCNTs, respectively.