Illuminating the Potential: Light Harvesting and Semiconducting Properties of Bacterial Microcompartment Shell Proteins

Biomaterials with self-assembly, genetic tunability, self-healing, and biocompatibility hold promise for next-generation electronics. This study explores disc-like shell proteins from bacterial microcompartments as photovoltaic materials. These self-assembling proteins exhibit semiconducting properties, including a low work function and non-linear I-V behavior. Notably, under UV light, they generate significant photocurrent without external voltage, demonstrating efficient electron transfer. Electron conduction occurs via tunneling, enabled by distinct electron-rich surface regions. High responsivity and quantum efficiency outperform prior protein-based systems, emphasizing their potential in photocurrent and light-harvesting applications. Genetic mutations revealed a proton-coupled electron transfer (PCET) mechanism, where tyrosine residues strategically positioned near proton abstraction sites enhance photocurrent generation. This study highlights the innovative capabilities of shell proteins for energy-efficient devices and demonstrates how genetic engineering can further optimize biomaterial performance, paving the way for sustainable electronic applications.