Recent Advancements in Doped/Co-Doped Carbon Quantum Dots for Multi-Potential Applications

Abstract

Carbon quantum dots (CQDs)/carbon nanodots are a new class of fluorescent carbon nanomaterials having an approximate size in the range of 2–10 nm. The majority of the reported review articles have discussed about the development of the CQDs (via simple and cost-effective synthesis methods) for use in bio-imaging and chemical-/biological-sensing applications. However, there is a severe lack of consolidated studies on the recently developed CQDs (especially doped/co-doped) that are utilized in different areas of application. Hence, in this review, we have extensively discussed about the recent development in doped and co-doped CQDs (using elements/heteroatoms—e.g., boron (B), fluorine (F), nitrogen (N), sulphur (S), and phosphorous (P)), along with their synthesis method, reaction conditions, and/or quantum yield (QY), and their emerging multi-potential applications including electrical/electronics (such as light emitting diode (LED) and solar cells), fluorescent ink for anti-counterfeiting, optical sensors (for detection of metal ions, drugs, and pesticides/fungicides), gene delivery, and temperature probing.

Microwave-Assisted Synthesis and Characterization of Poly(L-lysine)-Based Polymer/Carbon Quantum Dot Nanomaterials for Biomedical Purposes

“…Since then numerous preparation pathways have been developed. There are two main approaches to their obtainment which are called “top-down” and “bottom up” [1,2,3,4,10]. The main preparation strategies include chemical or laser ablation, electrochemical digestion, microwave-assisted conditions, and finally solvothermal or hydrothermal pathway.…”

“…This can be solved by applying post-treatment gel electrophoresis, dialysis, or centrifugation. Finally, very often the ready product surface properties such as water solubility, or selectivity are insufficient for their future applications [10,11,12,13,14,15].…”

“…The main drawback is low reaction yield and long reaction times, typically 12 h. A great alternative to aforementioned methods is a microwave irradiation approach. Organic material subjected to microwaves turns into carbon nanomaterials in a few minutes [1,2,3,4,10].…”

Carbon Dots as A Sustainable New Platform for Organic Light Emitting Diode

“…[47,48] Surface functionalization modifies the physical properties of CDs as their solubility in aqueous and non-aqueous solvents. In addition, the large conjugated structure endows CDs with some important characteristics, like good photostability, high surface area, and robust surface grafting [49]. Their electronic structures can be tuned by their size, shape, surface functional groups and heteroatom doping, as theoretical investigated and experimental confirmed by several groups [50][51][52][53][54].…”

Influence of Carbon Quantum Dots on the Biome

“…Of late, CQDs have been synthesized from cigarette waste [1,2,9] and have also been sourced from diesel exhaust [25]. Yet, studies concerning the environmental risks of CQDs to both plant and aquatic lifeforms appear to be largely inadequate and have been ignored.…”