| The existence of toxic heavy metal ions in water has seriously threatened the ecological environment and human health.It is an important task to realize the convenient detection of heavy metal ions in water pollution prevention and control.CuIn-Se quantum dots have been widely used in solar cells,biomedicine,environmental detection and other fields due to their excellent photoelectric performance and environmental friendliness.Based on the fluorescence regulation of Cu-In-Se quantum dots,this paper realizes the control of the luminescence range and luminescence intensity of quantum dots by studying the role of different surface ligands in the synthesis process,and finally builds a fluorescence sensor with the best fluorescence intensity of Zn-doped Cu-In-Se quantum dots for the detection and research of heavy metal ions in water.The main contents are as follows:(1)Optimization of optical properties of Zn-doped Cu-In-Se quantum dots based on synthesis technology.In Zn-doped Cu-In-Se quantum dots as a template,change the surface In the process of quantum dots synthesis ligand(oleamine,oleic acid or diphenyl phosphine),investigates the surface ligands in the anionic or cationic sources affect the performance of quantum dot fluorescent,by discussing different ligand role in quantum dot synthesis process,realize the fluorescence properties of quantum dots.The results show that the addition of oleamine-oleic acid mixed ligand to anion source can significantly enhance the fluorescence intensity of quantum dots,and the addition of olamine-oleic acid mixed ligand to cationic source can significantly promote the red shift of quantum dots.Adding diphenyl phosphine(DPP)into anion source can also significantly improve the fluorescence intensity.The fluorescence performance of quantum dot is the best when the dosage of DPP is 200μL and the reaction temperature is 175℃,and the higher temperature causes the fluorescence quenching.Before thermal injection of anions,different proportions of olamine-oleic acid mixed ligand were injected at 120℃ to achieve regulation of fluorescence emission wavelengths between 1000 nm-1300 nm.(2)Detection of heavy metal ions in water by Zn-doped Cu-In-Se quantum dots.Aqueous Zn-doped Cu-In-Se quantum dots were synthesized by ligand exchange using mercaptopropionic acid(MPA)and glutathione(GSH)as surface ligands to modify organic Zn-doped Cu-In-Se quantum dots.Through the optimization of reaction time,the fluorescence performance of water-phase quantum dots is the best at 30 min,and the quantum dots are used as fluorescence sensors to detect heavy metal ions in water.By adjusting the pH value of the reaction system for detecting heavy metal ions with fluore1cence probe,the fluorescence intensity of quantum dots is the best and Hg2+ and Pb2+ have the most obvious response to the quantum dots when the pH value is 5.In a certain concentration range,the fluorescence quenching intensity of quantum dots has a good linear relationship with the concentration of heavy metal ions.The linear correlation coefficient of Hg2+concentration in the range of 0-100 μM is 0.9496,and the linear correlation coefficient of Pb2+ concentration in the range of 0-20μM is 0.996. |
