Photoluminescence of carbon quantum dots: coarsely adjusted by quantum confinement effects and finely by surface trap states

Green Preparation of Fluorescent Carbon Quantum Dots from Cyanobacteria for Biological Imaging

“…Moreover, the lifetime of synthesized CQDs is composed of two proportions, involving a short-lived component τ 1 and long-lived component τ 2 . Previous works have pointed out that the lifetime τ 1 and τ 2 were related to the core states and surface states of CQDs, respectively [51,52,53]. In our case, the weight of τ 1 and τ 2 were determined to be 8.32% and 91.68%, respectively, and this result demonstrates that the PL emission is mainly controlled by the surface states induced by multiple functional groups within the structure of the CQDs.…”

Recent development of carbon quantum dots regarding their optical properties, photoluminescence mechanism, and core structure

“…Quantum confinement is occasionally used to explain the PL of CDs, but it is often used in conjunction with another concept such as surface state. 2,29,129,130 In 2018, Liu et al 130 prepared CDs from a perylene derivative and triethylamine and separated the resulting mixture using column chromatography. This yielded 25 fractions with emission ranging from blue to the near infrared.…”

A Perspective on Application of Carbon Quantum Dots in Luminescence Immunoassays

“…In all aforementioned methods, the final mixture, including residual starting materials and CQD particles with different sizes, are transferred into a dialysis bag or loaded onto a chromatographic column for further purification (Liu et al, 2018 ). Several techniques such as FT-IR, UV-visible, and photoluminescence (PL), x-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) have been extensively employed to characterize CQDs (Liu et al, 2016 ; Fu et al, 2019 ; Ma et al, 2019 ; Liu Y. et al, 2020 ).…”