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

Abstract

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 (0–2 wt%) of MWCNT. Field emission scanning electron microscope (FE‐SEM) images confirm the uniform dispersion of MWCNT and formation of conducting path above 0.3 wt% of MWCNT. The conductivity of the spin coated films is increased from 1 Scm−1 to ≈20 Scm−1 on addition of 2 wt% 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 74 Scm−1 and high stability upon bending to a radius of curvature ≈9.6 mm. 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 µsat = 1.16 cm2 V−1 s−1 with on/off ratio about 2.3 × 103. 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.

Wet‐Spun PEDOT/CNT Composite Hollow Fibers as Flexible Electrodes for H2O2 Production**

“…Compared to the pure PEDOT : PSS sample, the shoulder peaks disappear, which can be attributed according to literature to the high density of the CNT network. [30] The bands at 1265 cm À 1 and 1600 cm À 1 correspond to the graphite E 2g (G) mode and the disordered A 1g (D) mode of CNTs, which shows the successful CNT immobilization in the PEDOT matrix. In comparison to the pure CNT sample, the peaks are shifted.…”

“…This increase can be attributed to the well-dispersed CNTs forming conducting pathways within the composite material. The increasing loading of CNTs may help to build the network structure through the interpenetration of CNTs and PEDOT : PSS, [23] forming the percolating path of CNTs in the polymer matrix, [33] and the high tunnelling effect between CNT junctions. Due to the π-π interaction of CNTs and thiophene ring, the charges become more delocalized on the PEDOT : PSS chains, leading to electronic density transfer from PEDOT to CNTs.…”

“…[34] This optimum in conductivity for PEDOT : PSS/CNT composites with high CNT loadings has not been reported in the literature on composites with small CNT loadings. [23,35] In addition to the conductivity measurement, the influence of the CNT loading on the capacitance was analyzed. The measurement was performed in a specially designed test cell using a three-electrode setup as depicted in Figure S5.…”

“…[21,22] This crystallization process allows the synthesis of stable and highly conductive PEDOT parts in different geometries. [13,17,21,23] To the best of our knowledge, "acid-treated" PEDOT has not been investigated as a catalyst for the oxygen reduction reaction. However, it poses the advantages as mentioned above over the native PEDOT : PSS formulations.…”

Multifunctional Electronic Skin With a Stack of Temperature and Pressure Sensor Arrays

“…This is because the temperature sensing phenomenon in most of the organic materials are based on the charge transportation through tunnelling and hopping mechanism [36,49]. Further, the presence of CNT in the organic material network introduces new percolation path for fast transportation of charge carrier [53]. As a result, the sample 2 with CNT in PEDOT: PSS network exhibited fast response (2.5 s) and recovery (4.8 s) behaviour.…”