A facile and mass scalable method to obtain highly conductive and air stable poly(3,4-ethylenedioxythiophene) poly(4-styrenesulfonate) (PEDOT:PSS) formulation for transparent electrode using ultrafiltration was reported. PEDOT:PSS was synthesized by emulsion polymerization following the Baytron P procedure. Over-oxidation was avoided by controlling synthesis factors and the pristine PEDOT:PSS had relatively high conductivity. The final PEDOT:PSS dispersion consisted mainly of a complex of PEDOT:PSS, uncomplexed free PSS, and various impurities such as residual oxidants, 3,4-ethylenedioxythiophene oligomers, and excess electrolytes. The synthesized polymer dispersion was washed out of the cell through the membrane by distilled de-ionized (DDI) water, which flowed continuously into the ultrafiltration cell to maintain a stable concentration of PEDOT:PSS dispersion in the feed solution. PEDOT:PSS solutes were estimated to be almost 100 nm, since a small amount of unfiltered PEDOT:PSS was observed after filtration at 100 nm membrane pore size. The removal of PSS from PEDOT:PSS dispersion after ultrafiltration was confirmed by X-ray photoelectron spectroscope (XPS). The transparent and flexible PEDOT:PSS electrode was applied as S/D electrodes in printed OFETs by spray printing with a shadow mask. Purified PEDOT:PSS film showed better ambient stability as compare with the pristine PEDOT:PSS. CMOS inverters were demonstrated using DPPT-TT and P(NDI2OD-T2) FETs, and showed higher gain voltage and lower power consumption at supply voltage.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering