Enhanced Output from Biohybrid Photoelectrochemical Transparent Tandem Cells Integrating Photosynthetic Proteins Genetically Modified for Expanded Solar Energy Harvesting

A transparent biohybrid photoelectrochemical tandem cell is developed by employing optically-complementary variants of a photosynthetic protein in a stacked tandem architecture that utilizes a conductive polymer, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), as a transparent counter electrode. The tandem design demonstrates the photocurrent enhancement by complementary absorption of two naturally-occurring red and green versions of a bacterial Reaction center/Light Harvesting protein (RC-LH1) that vary in the type of light harvesting carotenoid feeding the central reaction center module with excited state energy. The use of PEDOT:PSS electrode results in a 12-fold improvement in photocurrent compared to that achievable with Platinum.