Utilizing Toray Paper as a Metal‐Free, High Surface Area Electrode for Photosystem I–Driven Mediated Electron Transfer

Abstract

One challenge in capitalizing on the affordability, sustainability, and accessibility of biohybrid solar energy conversion, including devices based on Photosystem I (PSI), is the identification of metal‐free electrode materials to replace the inorganic substrates commonly found in solar cell development. Herein, commercially available Toray carbon paper (CP) is investigated as a high surface area, carbon electrode for the development of photoactive bioelectrodes consisting of PSI and poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). Mediated anodic photocurrent is achieved at both PSI multilayer and PSI–polymer composite films on CP electrodes subjected to flame pretreatment. Film preparation is optimized by utilizing potential sweep voltammetry in place of potentiostatic conditions for polymerization. The optimized PSI–PEDOT:PSS films achieve a threefold increase in polymer growth under potential sweep conditions, quantified through net charge consumed during electropolymerization, resulting in a fourfold increase in photocurrent density (−53 vs −196 nA cm−2). The ability to prepare photoactive PSI‐polymer films on metal‐free CP electrodes opens the door to a rapidly scalable system for biohybrid energy production ultimately leading to more affordable, sustainable, and accessible energy.