Phenylalanine-Assisted Conductivity Enhancement in PEDOT:PSS Films

Biological materials such as amino acids are attractive due to their smaller environmental footprint, ease of functionalization, and potential for creating biocompatible surfaces for devices. Here, we report the facile assembly and characterization of highly conductive films of composites of phenylalanine, one of the essential amino acids, and PEDOT:PSS, a commonly used conducting polymer. We have observed that introducing aromatic amino acid phenylalanine into PEDOT:PSS to form composite films can improve the conductivity of the films by up to a factor of 230 compared to the conductivity of pristine PEDOT:PSS film. In addition, the conductivity of the composite films can be tuned by varying the amount of phenylalanine in PEDOT:PSS. Using DC and AC measurement techniques, we have determined that the conduction in the highly conductive composite films thus created is due to improvement in the electron transport efficiency compared to the charge transport in pure PEDOT:PSS films. Using SEM and AFM, we demonstrate that this could be due to the phase separation of PSS chains from PEDOT:PSS globules which can create efficient charge transport pathways. Fabricating composites of bioderived amino acids with conducting polymers using facile techniques such as the one we report here opens up opportunities for the development of low-cost biocompatible and biodegradable electronic materials with desired electronic properties.