Three-to four-times higher performance of biohybrid photoelectrochemical cells with photosynthetic reaction centers (RC) has been achievedb yu sing aD NA-basedb iomimetic antenna. Synthetic dyes Cy3 and Cy5 were chosen and strategically placed in the anntena in such aw ay that they can collect additional light energy in the visible region of the solar spectrum and transfer it to RC through Fçrster resonance energy transfer (FRET).T he antenna,aDNA templatedm ultiple dye system, is attached to each Rhodobacter sphaeroides RC near the primary donor,P ,t of acilitate the energy transfer process. Excitation with ab road light spectrum (approximating sunlight) triggers ac ascade of excitation energy transfer from Cy3 to Cy5 to P, and also directly from Cy5 to P. This additional excitation energy increases the RC absorbance cross-section in the visible and thus the performanceo ft he photoelectrochemical cells. DNA-based biomimetic antennas offer at unable, modular light-harvesting system for enhancing RC solar coverage and performance for photoelectrochemicalcells.The development of efficient biohybrid and biomimetic molecular devicesc apable of artificial photosynthesis requires photoelectrochemical components suitable for the streamlined transfer of light energy,e lectrons and molecules through effective molecular coupling. Rhodobacter (Rb.) sphaeroides reaction center (RC)-based photoelectrochemical cells have been popular as model systems in light energy transductionf or artificial fuel generation due to the RC's efficient photoinduced electron-hole separation and subsequent electron transfer to molecules.A dditional advantages are that RCs are robust and amenablet op rotein engineering and that their electron transfer reactionsh ave been well characterized.[1] Furthermore, it has recently been shown that the RC proteins can generate high photocurrents, [2] even foraprolonged time period under ambient atmosphericc onditions when they are self-assembled with cytochrome c ontoh ighly nanostructured conducting substrates. [3] In fabricating an efficient biomimetic photoelectrochemical devicef or RC-based solare nergy transduction, one must devise aw ay of maximizing sunlight absorption. In nature, RCs are surrounded by ah ighly-optimized auxiliary light-absorption system ("antenna") that broadens spectral coverage and transfers additional excitation energy to the RC, thus increasing the number of photons availabletot he RC.[4] Past work developing artificial antenna-RCs ystemsh as employed fluorescent quantum dots as efficient antennas based on Fçrster resonance energy transfer (FRET).[5] However,their large and spherical particle structure, as well as their binding via nonspecific electrostatic interactions, does not allow positional and directional control for the FRET process. To avoid this shortcoming, Milano et al. covalently attached small organic dyes to RCs and demonstrated efficient light absorption using ad ye-RC system. [6] More recently,i ncreasing degrees of sophistication in positional control and ...