Assembly of shell/core CDs@CaF2 nanocomposites to endow polymers with multifunctional properties

Novel ratiometric probe based on the use of rare earth-carbon dots nanocomposite for the visual determination of doxycycline

Rare earth-carbon dots (RE-CDs) hybrid nanomaterials with the merits of both RE and CDs have rapidly emerging as highly promising functional materials in biochemical analysis. In this work, a new kind of water-soluble RE-CDs nanocomposite (CDs@CaF₂:Eu³⁺) was developed for the ratiometric determination of doxycycline (DOX). The CDs@CaF₂:Eu³⁺ under the excitation at 365 nm displayed blue emission of CDs at 440 nm and no obvious emission of Eu³⁺. With the addition of DOX, substantial fluorescence quenching of the CDs at 440 nm and enhancement of Eu³⁺ at 613 nm were observed, resulting in a ratiometric fluorescent response toward DOX. A wide linear range from 0.1 µM to 30 µM was achieved in the detection of DOX with a lowest detection limit of 43 nM. In particular, the probe could discriminate DOX from other tetracycline antibiotics through unique fluorescence response. Moreover, we have successfully applied the method for the determination of DOX in milk and honey samples.

Self-formed C-dot-based 2D polysiloxane with high photoluminescence quantum yield and stability

C-Dots and composites based on them face the challenges of poor stability, especially under photo-radiation, and low solid-state photoluminescence quantum yields (PLQYs), which hinder their application in optical devices. Herein, a novel 2-dimensional hybrid material of polysiloxane embedded with Si-doped carbon dots (P-E-Si-CDs) was synthesized by a self-assembly approach, and the hybrid composite exhibited broadband blue-green fluorescence emission, outstanding photostability, high thermal stability, and a high PLQY of 82.8%. Moreover, the dual fluorescent emissions were demonstrated the creation of two closed-loop fluorophores. Using the as-prepared hybrid fluorescent material, fabricated light-emitting diodes (LEDs) based on UV and blue-emitting LED chips present safe warm white light emission and adjustable white emission with a high color rendering index of up to 91, respectively. This work provides a novel strategy for the design and realization of Si-CD-based hybrid composites, thus promising their prospective use commercially in LED lighting.

Fluorescent Carbon Quantum Dots-Synthesis,Functionalization and Sensing Application in FoodAnalysis

Carbon quantum dots (CQDs) with stable physicochemical properties are one of theemerging carbon nanomaterials that have been studied in recent years. In addition to the excellentoptical properties such as photoluminescence, photobleaching resistance and light stability, thismaterial also has favorable advantages of good biocompatibility and easy functionalization, whichmake it an ideal raw material for constructing sensing equipment. In addition, CQDs can combinedwith other kinds of materials to form the nanostructured composites with unique properties, whichprovides new insights and ideas for the research of many fields. In the field of food analysis,emerging CQDs have been deeply studied in food composition analysis, detection and monitoringtrace harmful substances and made remarkable research progress. This article introduces andcompares the various methods for CQDs preparation and reviews its related sensing applicationsas a new material in food components analysis and food safety inspection in recent years. It isexpected to provide a significant guidance for the further study of CQDs in the field of foodanalysis and detection. CQDs; synthesis; fluorescent sensing; food analysis.