Large-Scale One-Step Synthesis of Carbon Dots from Yeast Extract Powder and Construction of Carbon Dots/PVA Fluorescent Shape Memory Material

Fluorescent carbon dots (CDs) have drawn lots of attention for their excellent properties and broad applications. However, rarely hydrothermal methods of preparation have been investigated and reach a high synthetic yield of CDs, which limits their scale-up production. In this work, a large-scale one-step process is shown to prepare CDs from yeast extract powder (called y-CDs) for the first time and the yield of CDs can reach up to 65.8%. The optical properties and morphology of the y-CDs are characterized. On account of good water solubility and high yield of y-CDs, the application of the reprepared y-CDs/polyvinyl alcohol (PVA) as fluorescent shape memory material is explored. It turns out that the reprepared y-CDs/PVA not only exhibits bright blue luminescence under 365 nm UV light excitation, but also possesses shape memory behavior, which is superior to pure PVA. The interaction between y-CDs and PVA is explained and a water-responsive shape memory mechanism of the y-CDs/PVA composite films is introduced.