Optical Shading Induces an In‐Plane Potential Gradient in a Semiartificial Photosynthetic System Bringing Photoelectric Synergy

Abstract Semiartificial photosynthetic systems have opened up new avenues for harvesting solar energy using natural photosynthetic materials in combination with synthetic components. This work reports a new, semiartificial system for solar energy conversion that synergistically combines photoreactions in a purple bacterial photosynthetic membrane with those in three types of transition metal–semiconductor Schottky junctions. A transparent film of a common transition metal interfaced with an n‐doped silicon semiconductor exhibits an in‐plane potential gradient when a light‐penetration variance is established on its surface by optical shading of photoabsorbing photosynthetic membranes. The in‐plane potential gradients (0.08–0.3 V) enable a directional charge transport between the synthetic and natural photoelectric systems, which is further enhanced in a device setting by a biocompatible thixotropic gel electrolyte that permeates the membrane multilayer, facilitating a strong and steady photoelectric current as high as 1.3 mA cm −2 , the highest achieved so far with any anoxygenic photosynthetic system.