Improved PEDOT:PSS layers as an electrode on cellulose nanofiber substrates for solar cell applications

Abstract Cellulose nanofiber (CNF) films were used as model biodegradable substrate for flexible organic solar cells. To form transparent conductive electrodes compatible with CNF, the conductivity of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films was enhanced by two methods: additive doping of a low-conductivity source and a fast drop-spin solvent treatment of a high-conductivity source. The additive process increased conductivity from 3.48 × 10 −4 to 4.57 S cm −1 , while the drop-spin treatment improved it from 360 to 518 S cm −1 . Organic solar cells fabricated on CNF/glass substrates with improved-PEDOT:PSS films exhibited clear photovoltaic response, demonstrating the feasibility of acid-free, vacuum-free processing for CNF-based devices.