Figure 13.

The influence of size on the red shift of CDs. (A) The increase in the particle size leads to a red shift of the emission wavelength by reducing the energy gap of CDs. (B) Schematic representation of four different sizes of CDs with the different extent of π-conjugated domains of the resulting CDs. The colors represent the real PL color of the CDs. Seeded growth reaction leading to the formation of CDs and particle size changes. Adapted with permission from ²⁴⁶. Copyright 2021, John Wiley and Sons. (C) Correlation between HOMO and LUMO energy levels of CDs and their particle sizes. The downtrend in HOMO and LUMO levels leads to red shift of CDs. Adapted with permission from ²⁴⁷. Copyright 2021, John Wiley and Sons. (D) The degrees of dehydration and carbonization are gradually increased in water, glycerol, and DMF, resulting in the increased sp2-domains and red-shifted absorption and emission bands, which agree well with their increased particle sizes. Adapted with permission from ²⁴⁸. Copyright 2021, John Wiley and Sons.