Bacteriorhodopsin‐Based Biophotovoltaic Devices Driven by Chemiluminescence as Endogenous Light Source

Abstract As a light‐driven proton pump, bacteriorhodopsin (bR) captures light and transports protons directionally. Here, a new bR‐based bioelectronic device that employs the chemiluminescence from luminol as an endogenous light source to generate steady current is designed. Purple membrane embedded with bR is modified on indium tin oxide (ITO) electrode followed by electrostatically binding of cationic oligo (p‐phenylene vinylene) derivative (OPV). The device is fabricated by coupling bR/OPV electrode and bare ITO electrode. As a suitable luminescence acceptor of luminol, OPV emits green light through chemiluminescence resonance energy transfer (CRET), which is capable of exciting ground state bR (bR₅₇₀) nearby to initiate photocycle. Simultaneously, luminol emits blue chemiluminescent light which can be absorbed by M₄₁₀ intermediate in photocycle, accelerating its reconversion to bR₅₇₀ by shortcuts. As a result, the photocycle is accelerated and stabilized to generate a stable photocurrent. Furthermore, this study achieves to use oxygen and glucose as the initial source of hydrogen peroxide and produce stable photocurrent by taking advantage of the cascade reaction of glucose oxidase and horseradish peroxide. This provides a proof‐of‐concept for successfully using the CRET system as endogenous light source and provides new ideas for energy utilization and conversion taking advantage of natural bR‐based photosynthetic systems.