Microwave-assisted Sonochemical Synthesis Of Nanocomposites And Its Photoelectrochemical Detection

The photoelectrochemical(PEC)analysis technology uses the light as the excitation source,and the current signal as the detection signal.PEC1 materials are the basis of photoelectrochemistry,commonly used in the preparation of photoelectrochemical sensors.Because PEC sensor has the advantages of high sensitivity,selectivity and low cost,PEC technology is widely used in clinical analysis and the monitoring of environment pollutants.In this paper,functional constituents are used to synthesize functional materials in biological polypeptides,and use doping methods to improve their performance.Those PEC1 materials were successfully prepared by the microwave-assisted sonochemical synthesis technology.The main contents are as follows:1.Microwave-assisted sonochemical synthesis of GSH-CuxMnyZnS QDs and their photoelectric propertiesA series of Cu and Mn doped glutathione(GSH)-ZnS polypeptide quantum dots(QDs)were successfully prepared by a facile one-pot microwave-assisted sonochemical synthesis approach.Herein,GSH acted as a sulfide source and dispersant,as well as a reducing agent to form polypeptide QDs.The products were characterized by high-resolution transmission electron microscope(HR-TEM)and energy dispersive spectroscopy(EDS).Results show that the size of the polypeptides QDs was 2-3 nm.In Fourier transform infrared(FT-IR)spectra,the splitting of S-1 bonds and substitution by S-Zn can be noticed.The bonding interaction between Cu,Mn and Zn ions toward S was further confirmed from X-ray photoelectron spectroscopy(XPS)analysis.The results confirmed the partial Cu(Mn)substitution of Zn.Fluorescence(FL)spectra and UV-vis absorption spectra were used to investigate the optical properties.It was found that the doping of Cu and Mn could decrease the band gap of GSH-ZnS from 3.67 eV to 2.86 eV.The photoelectrochemical(PEC)properties of GSH-ZnS were enhanced due to the doping of Cu and Mn which has excellent chemical stability.The possible photoelectrochemical reaction mechanism is discussed.2.Microwave-assisted sonochemical synthesis of sensing interface and its response to Cu2+A PEC sensing interface for Cu2+ response was constructed.And Ag@BSA/ZnS@MPA nanocomposites(NCs)were prepared by microwave-assisted sonochemical synthesis technology.Microwave-assisted sonochemical synthesis technology has many advantages,such as easy to control parameters,mild reaction conditions,etc.The prepared Ag@BSA are uniform with an average diameter of 4 nm and have good conductivity.By absorbing the external energy(visible light),electrons are excited from the VB to CB.Effective charge transfer prevents the electron-hole recombination and enhances the photocurrent signal.In the absence of Cu2+,the Ag@BSA/ZnS@MPA composite structure contributes to the enhancement of the photocurrent signal.However,when the presence of Cu2+,the formation of CuxS(x =1,2)prevents electron transfer to the ITO electrode and reduces the photocurrent,which result in a response to Cu2+.