Molecular origin and self-assembly of fluorescent carbon nanodots in polar solvents

A Sharma, T Gadly, S Neogy, SK Ghosh… - The journal of …, 2017 - ACS Publications
The journal of physical chemistry letters, 2017ACS Publications
Despite numerous efforts, there are several fundamental ambiguities regarding the
photoluminescence of carbon dots (CDs). Spectral shift measurements display characteristic
of both π–π* and n–π* transitions for the main absorption or excitation band at∼ 350 nm,
contrary to common assignment of exclusive n–π* transition. Additionally, the generally
perceived core-state transition at∼ 250 nm, involving sp2-networked carbogenic domains
shielded from external environments, needs to be reassessed because it fails to explain the …
Despite numerous efforts, there are several fundamental ambiguities regarding the photoluminescence of carbon dots (CDs). Spectral shift measurements display characteristic of both π–π* and n–π* transitions for the main absorption or excitation band at ∼350 nm, contrary to common assignment of exclusive n–π* transition. Additionally, the generally perceived core-state transition at ∼250 nm, involving sp2-networked carbogenic domains shielded from external environments, needs to be reassessed because it fails to explain the observed fluorescence quenching and spectral shift. These results have been explained based on the molecular origin of PL in CDs invoking the similarity between CD and citrazinic acid. Fluorescent derivatives of the latter are recognized to be produced during citric-acid-based CD synthesis. Concentration-dependent spectral splitting of the main excitation band in combination with the temperature-dependent PL results has been envisioned assuming self-assembly of CDs into various H-aggregates.
ACS Publications
以上显示的是最相近的搜索结果。 查看全部搜索结果