The spectral modification of sunlight from less efficient green (500–600 nm) to more efficient red (600–700 nm) by light-converting fluorescent dyes has been widely studied for enhancing the microalgal biomass productivity. In particular, deep-red (650–700 nm) photons, which are mainly used by photosynthetic pigments of microalgae for photosynthesis, play a key role in promoting microalgal growth. In this study, we have synthesized three different deep-red emitting diketopyrrolopyrrole (DPP) dyes and utilized two of them to fabricate light-converting films for microalgal cultivation. The introduction of free-rotatable triphenylamine (TPA) moieties into DPP dyes enabled them to exhibit excellent solid state emission via aggregation-induced emission (AIE). As a result, cultured microalgae showed different biomass and lipid productivity according to the degree of increase in the photosynthetic photon flux density (PPFD) of the light-converting films. In detail, strong deep-red emission of the light-converting film prepared using dye E2 increased the total fatty acid methyl ester (FAME) content of microalgae up to 62.4%. In contrast, the weak deep-red emission of the light-converting film based on dye M2 resulted in an enhancement of only 28.8%. These results show that the deep-red emitting AIE-DPPs could potentially be applied in light-converting film materials for accelerating the mass production of microalgae.

中文翻译：

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基于二酮吡咯并吡咯的高效光转换膜具有深红色聚集诱导发射，用于提高小球藻的脂质生产力。

通过光转换荧光染料将太阳光从效率较低的绿色（500-600 nm）光谱修改为更有效的红色（600-700 nm）已被广泛研究以提高微藻生物质生产力。特别是深红色（650-700 nm）光子，主要被微藻的光合色素用于光合作用，在促进微藻生长方面起着关键作用。在这项研究中，我们合成了三种不同的深红色二酮吡咯并吡咯 (DPP) 染料，并利用其中的两种来制造用于微藻培养的光转换膜。将可自由旋转的三苯胺 (TPA) 部分引入 DPP 染料使它们能够通过聚集诱导发射 (AIE)。结果，根据光转换膜的光合光子通量密度（PPFD）的增加程度，培养的微藻显示出不同的生物量和脂质生产力。具体而言，使用染料E2制备的光转换膜的强烈深红色发射使微藻的总脂肪酸甲酯 (FAME) 含量增加了 62.4%。相比之下，基于染料M2的光转换膜的弱深红色发射导致仅 28.8% 的增强。这些结果表明，发射深红色的 AIE-DPPs 有可能应用于光转换膜材料，以加速微藻的大规模生产。