Spectral down-shifting colloidal quantum dot solids for enhanced photosynthetic biofuel production

초록

Photosynthetic microalgae-based biofuel production has attracted significant attention as a sustainable energy source; however, natural solar irradiance, air mass (AM) 1.5G, exhibits a non-ideal photon spectrum for efficient photosynthesis. In this study, we demonstrated that a spectral down-shifting colloidal quantum dot (SD-CQD) solid could effectively modulate natural solar irradiance into a photosynthesis-friendly spectrum. By leveraging quantum confinement, we tailored the emission wavelength of the core/shell CQDs to align with the chlorophyll Qy band (650–700 nm), the most effective wavelength range for microalgal photosynthesis. The results of theoretical studies and a careful synthesis optimization revealed that the Qy/Soret band (400–450 nm) ratio (Q/S) governed photosynthetic regulation, maximizing photosystem II (PSII) stability and energy utilization by enhancing electron transport and minimizing excess energy loss. This platform maintained an optimized Q/S of 1.95 under fluctuating outdoor sunlight conditions, delivering a consistent light quality. Finally, we demonstrated large-area and robust SD-CQD solids that could be sustainably deployed throughout the photosynthetic microalgal cultivation process. A SD-CQD-solid-utilizing photobioreactor exhibited 41.75% and 121.79% increases in biomass and hexadecenoic acid (C16:1) productivity, respectively, achieving a solar-to-biomass energy conversion efficiency 1.53-fold higher than that of the conventional system. © 2026 Elsevier B.V.

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