Evolution and Synthesis of Carbon Dots: From Carbon Dots to Carbonized Polymer Dots

Abstract

Despite the various synthesis methods to obtain carbon dots (CDs), the bottom‐up methods are still the most widely administrated route to afford large‐scale and low‐cost synthesis. However, as CDs are developed with increasing reports involved in producing many CDs, the structure and property features have changed enormously compared with the first generation of CDs, raising classification concerns. To this end, a new classification of CDs, named carbonized polymer dots (CPDs), is summarized according to the analysis of structure and property features. Here, CPDs are revealed as an emerging class of CDs with distinctive polymer/carbon hybrid structures and properties. Furthermore, deep insights into the effects of synthesis on the structure/property features of CDs are provided. Herein, the synthesis methods of CDs are also summarized in detail, and the effects of synthesis conditions of the bottom‐up methods in terms of the structures and properties of CPDs are discussed and analyzed comprehensively. Insights into formation process and nucleation mechanism of CPDs are also offered. Finally, a perspective of the future development of CDs is proposed with critical insights into facilitating their potential in various application fields.

Graphene quantum dot based materials for sensing, bio-imaging and energy storage applications: a review

“…In CPDs molecular states, surface states, subdomain states and crosslink emission effect is mainly responsible for photoluminescence properties. 16 A detailed review of the evaluation of carbon dots and classication based on the structure and properties is done by Xia et al 16 In the past decade, researchers have worked on the successful development of 0D GQDs in lines of the 2D graphene. GQDs consist of a monolayer or a few monolayers of graphene-related to quantum connement and edge effects.…”

Fluorescent Carbonized Polymer Dots Prepared from Sodium Alginate Based on the CEE Effect

“…The cross-linking structure of the precursors resulted in a more compact internal structure of CPDs, which enhanced the group interaction and changed energy gaps, leading to the red shifts of both the absorption and emission. 5 The quantum yields (QYs) of the two CPDs were 2% for SA-CPDs and 11% for SG-CPDs, showing that the cross-linking process greatly improved the fluorescence intensity because of the restriction of nonradiation relaxation de-excitation process caused by the vibration and rotation of subfluorophores, as illustrated in Scheme 1 . Moreover, the QY of SG-CPDs was found to be closely related to the amount of glutaraldehyde, as shown in the inset picture of Figure 2 b, probably because the strongest cross-linking extent was achieved with the molar ratio of SA/glutaraldehyde about 2.66.…”

Nitrogen‐Doped Carbonized Polymer Dots: A Potent Scavenger and Detector Targeting Alzheimer's β‐Amyloid Plaques

“…[28,29] CPDs as a kind of carbon dots show many excellent characteristics, such as long-wavelength excitation and emission, good biocompatibility, desired blood brain barrier penetration ability, and high quantum yield. [30] Moreover, the red fluorescence of CPDs has less phototoxicity to tissues, lower biological fluorescence background, and higher tissue penetration ability than other shortwavelength fluorescence probes. [29,[31][32][33] Herein, we report the newly discovered functions of CPDs in inhibiting Aβ fibrillogenesis, rapidly disaggregating Aβ mature fibrils, and emitting enhanced red fluorescence once binding to Aβ aggregates.…”