Affiliation:
1. Electro-holography Lab. Department of Electrical and Computer Engineering Brigham Young University Provo UT 84602 USA byu.edu
Abstract
This paper shows a four‐order reduction of magnitude in sheet resistance for spin‐coating poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) onto polyvinylidene fluoride (PVDF) film for a final sheet resistance comparable to commercially available indium tin oxide‐ (ITO‐) coated PVDF film. The resulting PEDOT:PSS transparency is 10% less than the transparency for ITO:PVDF. This is done by the combination of four techniques from the literature including (i) varying layers, (ii) plasma etching, (iii) post‐treatment submersion in an ethylene glycol (EG) bath, and (iv) adding EG and a surfactant to the PEDOT:PSS solution. The PEDOT:PSS sheet resistance falls from over 3 megaohms/sq to between 600 and 150 ohms/sq depending on the number of layers. The one‐layer sample has a sheet resistance of 600 ohms/sq and an optical transparency of about 76%, and the five‐layer sample has a sheet resistance of 150 ohms/sq and an optical transparency of about 50%. These results reported here make PEDOT:PSS an attractive option for transparent piezoelectric micromachined ultrasonic transducer (PMUT) array applications.