| Summary: | 碩士 === 中原大學 === 物理研究所 === 104 === Solution-processed carbon dots (CDs) have attracted much attention owing to their superior materials and photoluminescence (PL) properties, such as abundant precursor materials, less toxicity, high photo-stability and tunable emission. However, their PL properties, including PL quantum yields and photo-stability would be significantly degraded due to concentration-induced solid-state quenching and unstable surface. In this thesis, we fabricated high quality CDs/polyvinyl alcohol (PVA) light-emitting flexible films with submicron structure patterns by a facile and low cost method. PVA is chosen as the host matrix to both disperse and passivate CDs, leading to enhanced internal quantum yields (69%) in the solid states. Patterned CDs/PVA composite can be used to extract the trapped light, thus mitigate the waveguide-mode losses, approximately doubling the external light extraction efficiency. Such CDs/PVA composites also exhibit good photo-stability, and can be used as eco-friendly, low cost phosphors for solid-state lighting.
On the other hand, those CDs can also be utilized as eco-friendly luminophores for promising applications in luminescent solar concentrators (LSCs). Such LSCs can be used to concentrate the solar light to enhance the efficiency and reduce the material costs of solar cells. We have fabricated flexible LCSs based on hydrophobic CDs doped PDMS waveguide and characterize their performances using spectroscopic methods. We found that those hydrophobic CDs can be uniformly dispersed into PDMS waveguide and exhibit good photo-stability. The key metric of LSCs, namely, reabsorption losses, has also been investigated using excitation-position-dependent PL spectroscopy. Our demonstration can pave a way to further design efficient LSCs based on eco-friendly CDs in the future.
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