Synthesis, optical properties and applications of red/near-infrared carbon dots

Abstract

Compared to inorganic quantum dot, carbon nanoparticles or carbon quantum dots (C-dots) have gained significant attentions because of their unique optoelectrical properties and less toxicity. Although many review articles summarize...

Searching for the true origin of the red fluorescence of leaf-derived carbon dots

“…These properties have shown promising potential for applications in drug delivery, 2 bioimaging, 3,4 fluorescent sensing, 5 optoelectronic devices, [6][7][8][9] photocatalysis, 10 electrocatalysis 11 and information encryption. [12][13][14] In addition, due to the unique optical and photoelectric properties of red-emitting CDs in the red/near infrared region, these interesting CDs can be used as an important building block for applications ranging from bioimaging 15,16 and LEDs 17 to photophysics. [18][19][20] Conventional synthesis methods of CDs usually require toxic chemicals or organic solvents as precursors, thus increasing environmental and energy consumption issues.…”

Recent advances in red-emissive carbon dots and their biomedical applications

“…are mainly used and subjected to relatively severe external conditions such as electrochemical exfoliation, laser ablation, chemical oxidation, and arc discharge to cut large carbon materials into small carbon particles less than 10 nm in size. [24][25][26][27] The top-down synthesis strategy realizes the conversion of multi-dimensional carbon materials to zero-dimension, further expanding the carbon research field. However, the limited options of raw materials, complicated preparation processes, and relatively low product yields lead to the high cost of CD preparation through the topdown method.…”

Comprehensive advances in the synthesis, fluorescence mechanism and multifunctional applications of red-emitting carbon nanomaterials

“…[48][49][50][51] Amino acids, citric acids, naphthalene, saccharides, phenylenediamines, polythiophene, etc., are the most frequently employed small organic materials to synthesize far-red or near IR emissive CNMs. 52,53 Citric acid has a carboxylic functional group, which rapidly reacts with nitrogen containing amino groups to form fused a, b or a, g bi-amines. This alkylation reaction results as the increasing of carbonization degree with nitrogen content, continuing the formation of -C]C-, -C]N-, -C]O-, and -C-NHbonds to produce 2-pyridone fused large organic rings, followed by the reduction of the band gap between the HOMO and LUMO.…”