Hot‐Tailoring of Carbon Nitride Dots with Redshifted Photoluminescence for Visual Double Text Encryption and Bioimaging

Abstract

The fabrication of carbon dots and their doped forms by top‐down chemical cleavage has attracted considerable attention in the efforts to meet the increasing demands for optoelectronic applications ranging from biosensing to electro‐ and photocatalysis. However, due to strong quantum confinement effects, the size decrease often leads to an increase in the band gap, even in the emission of deep‐ultraviolet (DUV) light, which greatly limits their applications. Here, we report a facile hot‐tailoring strategy for fabricating carbon nitride nanodots (CNDs) with redshifted intrinsic photoluminescent (PL) emission, compared with the pristine bulk precursor. It has been found that the different leaving abilities of the C,N‐containing groups during the pyrolysis stage and the chemical passivation during the liquid‐collection stage played vital roles. Due to the redshifted photoluminescence and other attractive features, the as‐obtained CNDs were successfully applied in visual double text encryption with higher security and also in bioimaging with photostability superior to traditional dyes. This work highlights the great potential of the hot‐tailoring method in modulating carbon‐based nanostructures and offsetting band‐gap widening as the size decreases.

Structure and Interface Modification of Carbon Dots for Electrochemical Energy Application

“…The "top-down" strategy breaks down larger carbon structures into nanoscale CDs. [29a] "Top-down" synthesizing paths include hot-tailoring, [36] laser ablation, [37] arc discharge, [38] electrochemical method, [39] acid oxidation insolvent or vapor [40] and hydrothermal/solvothermal cutting. [41] Deserve to be mentioned, acid oxidation and hydrothermal cutting are the most common ways to synthesize CDs through "top-down" strategies.…”

Property of carbon dots and their applications in biosensor

“…图 13 用于腺苷检测的化学发光传感器的检测机制 [101] (网 络版彩图) Figure 13 Detection mechanism of chemiluminescence sensor for adenosine detection [101] (color online). 图 14 CDs-NaNO 2 -H 2 O 2 系统的CL机理示意图 [102] (网络版 彩图) [57] , 如通过掺杂N原子, 使CDs的FL发射发生红 移 [107] . (4) 由于目前合成的大部分CDs的结构具有不 确定性, 导致对CDs特性的研究还存在一定的局限 [108] .…”

“…制备确定结构的CDs是目前合成的一个研究方向, 已 有研究人员将大块聚合物氮化碳作为前驱体, 通过化 学剪裁制备结构确定的氮化石墨烯量子点 [107,109] . 虽 然CDs作为一个新兴纳米材料从2004年被发现到如今 只过了十余年, 但在生物传感方面已表现出了极大的 潜力.…”

Encrypted and tunable graphene‐based metasurface refractive index sensor

“…Biosensors are used not only for sensing biomolecules but they are also used in encryption applications. 1,2 Biosensors are used for sensing hemoglobin (HT) and urine biomolecules. 3,4 They are also used for sensing glucose and other proteins, which is applicable in diagnostic applications.…”