High sensitivity ratiometric fluorescence temperature sensing using the microencapsulation of CsPbBr3 and K2SiF6:Mn4+phosphor

A dual emission sensing film has been prepared for colorimetric temperature sensing using CsPbBr_(3)perovskite nanocrystals(CsPbBr_(3)NCs)and manganese doped potassium fluorosilicate(K_(2)SiF_(6):Mn^(4+),KSF)encapsulated in polystyrene by a microencapsulation strategy.The CsPbBr_(3)-KSF-PS film shows good temperature sensing response from 30℃to 70℃,with a relative temperature sensitivity(Sr)up to 10.31%℃^(−1) at 45℃.Meanwhile,the film maintains more than 95%intensity after 6 heating-cooling cycles and keeps its fluorescence characteristics after 3 months.The film can be used to monitor temperature change by naked eye under a UV lamp.In particular,the temperature discoloration point of the sensing film can be controlled by the ratio change of CsPbBr_(3):KSF to expand its applications.The study of the CsPbBr_(3)-KSF-PS sensing mechanism in this work is helpful to provide effective strategies for the design of reliable,high sensitivity and stable temperature sensing system using CsPbBr_(3)NCs.

Study of the effect of chemical composition on the surface wettability of three-dimensional graphene foams

The chemical composition obviously affects the surface wettability of a three-dimensional(3D)graphene material apart from its surface energy and microstructure.In the hydrothermal preparation,the heteroatom doping changes the chemical composition and wettability of the 3D graphene material.To realize the controllable surface wettability of graphene materials,aminobenzene sulfonic acid(ABSA)was selected as a typical doping agent for the preparation of nitrogen and sulfur co-doped 3D graphene foam(SNGF)using a hydrothermal method.Different from using o-ABSA or p-ABSA as the dopant,SNGF with tunable surface wettability is obtained only when m-ABSA is used.This result indicates that the substituent position of-SO3H group in the benzene ring of ABSA is rather important for the tunable wettability.This work provides some theo retical foundations for dopant selection and some new insights in manipulating the properties of 3D graphene foams by adjusting the configuration of dopants.

Automated Determination of Cd^(2+) and Pb^(2+) in Natural Waters with Sequential Injection Analysis Device Using Differential Pulse Anodic Stripping Voltammetry

An electrochemical flow device has been developed for the determination of heavy metal ions(HMI)in water using multiwalled carbon nanotubes(MWCNTs)/Nafion(NA)/Hg electrode,by mean of diff erential pulse anodic stripping voltammetry coupled with sequential injection analysis.The accuracy of the determination was ensured by the great electrical conductivity of MWCNTs and the high adsorption capacity of Hg.NA was used for MWCNTs immobilization for the long-term application of the electrode.The mercury film was cleaned after determination and another one would form during deposition.A lower limit of detection and a wider determination range of Cd^(2+)and Pb^(2+)could be achieved using the automatically analytical device combining with the MWCNTs/NA/Hg-modified electrode.The real-time monitoring of Cd^(2+)and Pb^(2+)in fresh water using this device continued for 10 days.The results indicated that the method was potential for on-site and real-time determination of HMI in water samples.