Role of Aromatic Amino Acids in Enhancing the Optical Transmissivity of PEDOT:PSS*

Transparent conductors such as indium tin oxide is used in technologies where light needs to penetrate the electrode layer such as touchscreen displays and photovoltaic cells. Thin films of polymer mixture poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), one of the commonly used stable conducting polymer, has been suggested as alternative due to their high conductivity when mixed with organic solvents and high transmissivity. Here, we report that not only the conductivity but also the optical transmittivity of PEDOT: PSS can be further enhanced by introducing aromatic amino acids in the mixture before constructing thin films. We have explored the conductivity and transmissity of film with all four aromatic amino acids – Histidine, Phenylalanine, Tryptophan and Tyrosine. Using amino acids as dopants to enhance optical transmissivity of thin films presents as cost-effect and environmentally friendly alternative to develop transparent electrodes.