Phenylalanine Assisted Conductivity Enhancement in PEDOT:PSS Films

<br/>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 facile self-assembly and characterization of highly conductive films of composites of phenylalanine, an aromatic amino acid, and PEDOT:PSS, a commonly used conducting polymer, which has been shown to have increased conductivity when doped with polar organic compounds. However, the behavior observed with Phenylalanine is significant because it is non-polar in nature and is biologically derived. We have observed that the composite films formed by introducing aromatic amino acid phenylalanine in PEDOT:PSS can improve the conductivity of the film to about 594 S/cm, a 400% increment compared to the conductivity of a pristine PEDOT:PSS film of about 1.5 S/cm. In addition, the conductivity remains high even with a 10 vol% PEDOT:PSS solution. These conductive properties show a clear trend with changed proportions and the composites appear physically distinct. Using DC and AC measurement techniques, we have determined that the conduction in the highly conductive composites is purely due to efficient electron transport compared to pure PEDOT:PSS films. As observed from SEM and AFM, this is likely due to the phase separation of PSS chains from PEDOT:PSS globules which has previously been shown to increase conductivity since PSS regions impede charge transport. Fabricating composites of bioderived simple 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.