Optical Properties of Ultrathin Biohybrid Membranes: Implications for Optoelectronic Applications

Biohybrid membranes, combining a self-assembled lipid bilayer structure with functional nanomaterials/molecules, are promising candidates for ionic, optical, and electronic applications. However, information concerning the basic properties of these types of ultrathin hybrid membranes remains limited, primarily due to their low structural strength and low stability in air. In this work, we report on the successful formation of large-area ultrathin hybrid membranes composed of lipid and phthalocyanine molecules. The basic optical properties, mainly the light absorption and light emission properties, of the membranes were systematically investigated. The phthalocyanine molecules did not form an ordered crystal structure and were partially aggregated and dispersed in the hybrid membranes. Because the phthalocyanine molecules and the substrate were separated only by a monolayer of lipid molecules, the light-excited phthalocyanine molecules transferred the absorbed energy to the metal substrate, which led to the quenching of the emitted light. These unique properties of the hybrid membranes could be utilized in a variety of optoelectronic applications such as bioelectronic interfaces and photodetectors.