Solution Processable PEDOT:PSS/Multiwalled Carbon Nanotube Composite Films for Flexible Electrode Applications

摘要

High-performance flexible optoelectronic devices have great potential as active elements for flexible and wearable electronics. The authors report highly flexible conducting poly (3, 4-ethylene dioxythiophene):polystyrene sulfonate/multiwalled carbon nanotubes (PEDOT:PSS/MWCNT) composite thin films synthesized by simple, cost effective rod-coating technique. The effect of MWCNT on PEDOT:PSS matrix is analyzed by spin coating PEDOT:PSS/MWCNT composite on glass substrates with varying concentration (0–2wt%) of MWCNT. Field emission scanning electron microscope (FE-SEM) images confirm the uniform dispersion of MWCNT and formation of conducting path above 0.3wt% of MWCNT. The conductivity of the spin coated films is increased from 1Scm~(-1) to ≈20Scm~(-1) on addition of 2wt% of MWCNT. From UV-Vis NIR spectra, the transparency of composite films in the visible range (at 550 nm) is found to decrease with respect to MWCNT loading. The PEDOT:PSS/MWCNT flexible electrode exhibit high electrical conductivity of 74Scm~(-1) and high stability upon bending to a radius of curvature≈9.6mm. The features observed are an outcome of the interaction of MWCNT with PEDOT polymer as the back bone. These films are adhered to the substrate and the properties are stable upon bending the film for large number of cycles. To demonstrate the potential use of this composite film as an electrode, a thin film transistor is fabricated with PEDOT:PSS/MWCNT film as source and drain electrode. The device shows high field effect mobility of μ_(sat)=1.16cm~2V~(-1) s~(-1) with on/off ratio about 2.3×10~3. These favorable results make PEDOT:PSS/ MWCNT conducting electrode as an excellent candidate for the next generation flexible electrodes realized by a facile solution process.