2021, Vol.7 No.3 Thecoverpictureshows that the thermal processing of citric acid and urea
resulted in some relatively minor carbonization and also significant thermally
induced chemical reactions for the formation of molecular dyes and/or
chromophores, which were incorporated with crosslinking into the
“nano-carbon/organic hybrids”. Some of
the molecular dyes and/or chromophores were red/near-IR absorptive and
fluorescent, which prompted erroneous claims of the hybrid samples as
“red/near-IR carbon dots”. More details are discussed in the article by Sun et al. on page 210011.