Liang, Weixiong published the artcileOn the myth of ”red/near-IR carbon quantum dots” from thermal processing of specific colorless organic precursors, Recommanded Product: N-Methylformamide, the main research area is carbon quantum dot thermal processing organic precursor red nearIR.
Carbon dots were originally found and reported as surface-passivated small carbon nanoparticles, where the effective surface passivation was the chem. functionalization of the carbon nanoparticles with organic mols. Understandably, the very broad optical absorptions of carbon dots are largely the same as those intrinsic to the carbon nanoparticles, characterized by progressively decreasing absorptivities from shorter to longer wavelengths. Thus, carbon dots are generally weak absorbers in the red/near-IR and correspondingly weak emitters with low quantum yields. Much effort has been made on enhancing the optical performance of carbon dots in the red/near-IR, but without meaningful success due to the fact that optical absorptivities defined by Mother Nature are in general rather inert to any induced alterations. Nevertheless, there were shockingly casual claims in the literature on the major success in dramatically altering the optical absorption profiles of ”carbon dots” by simply manipulating the dot synthesis to produce samples of some prominent optical absorption bands in the red/near-IR. Such claims have found warm receptions in the research field with a desperate need for carbon dots of the same optical performance in the red/near-IR as that in the green and blue. However, by looking closely at the initially reported synthesis and all its copies in subsequent investigations on the ”red/near-IR carbon dots”, one would find that the ”success” of the synthesis by thermal or hydrothermal carbonization processing requires specific precursor mixtures of citric acid with formamide or urea. In the study reported here, the systematic investigation included precursor mixtures of citric acid with not only formamide or urea but also their partially methylated or permethylated derivatives for the carbonization processing under conditions similar to and beyond those commonly used and reported in the literature. Collectively all of the results are consistent only with the conclusion that the origins of the observed red/near-IR optical absorptions in samples from some of the precursor mixtures must be mol. chromophores from thermally induced chem. reactions, nothing to do with any nanoscale carbon entities produced by carbonization.
Nanoscale Advances published new progress about Carbon quantum dots. 123-39-7 belongs to class amides-buliding-blocks, name is N-Methylformamide, and the molecular formula is C2H5NO, Recommanded Product: N-Methylformamide.
Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics