Optically Matched Semiconductor Quantum Dots Improve Photophosphorylation Performed by Chloroplasts.

A natural-artificial hybrid system was constructed to enhance photophosphorylation. The system comprises chloroplasts modified with optically matched quantum dots (chloroplast-QD) with a large Stokes shift. The QDs possess a unique optical property and transform ultraviolet light into available and highly effective red light for use by chloroplasts. This favorable feature enables photosystem II contained within the hybrid system to split more water and produce more protons than chloroplasts would otherwise do on their own. Consequently, a larger proton gradient is generated and photophosphorylation is improved. At optimal efficiency activity increased by up to 2.3 times compared to pristine chloroplasts. Importantly, the degree of overlap between emission of the QDs and absorption of chloroplasts exerts a strong influence on the photophosphorylation efficiency. The chloroplast-QD hybrid presents an efficient solar energy conversion route, which involves a rational combination of a natural system and an artificial light-harvesting nanomaterial.