The aim of this research was to investigate the luminescent behavior of ultra-small Eu3+-activated phosphate and vanadate nanoparticles in the presence of pesticides.Nanoparticles have an average diameter of approxima...The aim of this research was to investigate the luminescent behavior of ultra-small Eu3+-activated phosphate and vanadate nanoparticles in the presence of pesticides.Nanoparticles have an average diameter of approximately 2 nm with a narrow size distribution.The monazite crystal structure of phosphate-based particles(space group P121/n1)and single tetragonal zircon-type structure of vanadate-based particles(space group of I41/amd)have been confirmed using X-ray diffraction measurements.All synthesized Eu3+-activated colloidal nanoparticles show sharp emission peaks in the red spectral region.Photoluminescence measurements revealed emission quenching upon addition of millimolar concentrations of following pesticides:4-Chloro-2-methyl-phenoxyacetic acid(MCPA),2,4-Dichlorophenoxyacetic acid(2,4-D)and N-(phosphonomethyl)glycine(Glyphosate).In both phosphate and vanadate-based colloidal nanoparticles luminescence quenching is more evident in the presence of 2,4-D pesticide with the lowest limit of detection(0.7μM)obtained for phosphate-based nanoparticles.展开更多
The near-infrared luminescence of Ca_(6)Ba(PO_(4))_(4)O∶Mn^(5+)is demonstrated and explained.When excited into the broad and strong absorption band that spans the 500-1000 nm spectral range,this phosphor provides an ...The near-infrared luminescence of Ca_(6)Ba(PO_(4))_(4)O∶Mn^(5+)is demonstrated and explained.When excited into the broad and strong absorption band that spans the 500-1000 nm spectral range,this phosphor provides an ultranarrow(FWHM=5 nm)emission centered at 1140 nm that originates from a spin-forbidden ^(1)E → ^(3)A_(2) transition with a 37.5%internal quantum efficiency and an excited-state lifetime of about 350 μs.We derived the crystal field and Racah parameters and calculated the appropriate Tanabe-Sugano diagram for this phosphor.We found that 1E emission quenches due to the thermally-assisted cross-over with the ^(3)T_(2) state and that the relatively high Debye temperature of 783 K of Ca_(6)Ba(PO_(4))_(4)O facilitates efficient emission.Since Ca_(6)Ba(PO_(4))_(4)O also provides efficient yellow emission of the Eu^(2+)dopant,we calculated and explained its electronic band structure,the partial and total density of states,effective Mulliken charges of all ions,elastic constants,Debye temperature,and vibrational spectra.Finally,we demonstrated the application of phosphor in a luminescence intensity ratio thermometry and obtained a relative sensitivity of 1.92%K^(-1) and a temperature resolution of 0.2 K in the range of physiological temperatures.展开更多
基金support from the National Recruitment Program of High-end Foreign Experts(Grant No.GDT20185200479)offered by the Chongqing University of Posts and Telecommunications(CQUPT),Chinafinancial support of the Ministry of Education,Science and Technological Development of the Republic of Serbia(Nos.45020 and 172056).
文摘The aim of this research was to investigate the luminescent behavior of ultra-small Eu3+-activated phosphate and vanadate nanoparticles in the presence of pesticides.Nanoparticles have an average diameter of approximately 2 nm with a narrow size distribution.The monazite crystal structure of phosphate-based particles(space group P121/n1)and single tetragonal zircon-type structure of vanadate-based particles(space group of I41/amd)have been confirmed using X-ray diffraction measurements.All synthesized Eu3+-activated colloidal nanoparticles show sharp emission peaks in the red spectral region.Photoluminescence measurements revealed emission quenching upon addition of millimolar concentrations of following pesticides:4-Chloro-2-methyl-phenoxyacetic acid(MCPA),2,4-Dichlorophenoxyacetic acid(2,4-D)and N-(phosphonomethyl)glycine(Glyphosate).In both phosphate and vanadate-based colloidal nanoparticles luminescence quenching is more evident in the presence of 2,4-D pesticide with the lowest limit of detection(0.7μM)obtained for phosphate-based nanoparticles.
基金The authors from Serbia acknowledge funding from the Ministry of Education,Science,and Technological Development of the Republic of Serbia.M.D.D.recognizes the support from the Chinese National Foreign Experts Program for“Belt and Road Initiative"Innovative Talent Exchange(Grant No.DL2021035001L)M.G.B.thanks the support from the Program for Foreign Experts(Grant No.W2017011)offered by Chongqing University of Posts and Telecommunications+2 种基金Estonian Research Countil grant PUT PRG111,European Regional Development Fund(TK141),NCN project 2018/31/B/ST4/00924 and 2021/40/Q/ST5/00336C.G.M.acknowledges the support of the National Natural Science Foundation of China(Grant No.52161135110)China-Poland Intergovernmental Science and Technology Cooperation Program(Grant No.2020[15]/10).
文摘The near-infrared luminescence of Ca_(6)Ba(PO_(4))_(4)O∶Mn^(5+)is demonstrated and explained.When excited into the broad and strong absorption band that spans the 500-1000 nm spectral range,this phosphor provides an ultranarrow(FWHM=5 nm)emission centered at 1140 nm that originates from a spin-forbidden ^(1)E → ^(3)A_(2) transition with a 37.5%internal quantum efficiency and an excited-state lifetime of about 350 μs.We derived the crystal field and Racah parameters and calculated the appropriate Tanabe-Sugano diagram for this phosphor.We found that 1E emission quenches due to the thermally-assisted cross-over with the ^(3)T_(2) state and that the relatively high Debye temperature of 783 K of Ca_(6)Ba(PO_(4))_(4)O facilitates efficient emission.Since Ca_(6)Ba(PO_(4))_(4)O also provides efficient yellow emission of the Eu^(2+)dopant,we calculated and explained its electronic band structure,the partial and total density of states,effective Mulliken charges of all ions,elastic constants,Debye temperature,and vibrational spectra.Finally,we demonstrated the application of phosphor in a luminescence intensity ratio thermometry and obtained a relative sensitivity of 1.92%K^(-1) and a temperature resolution of 0.2 K in the range of physiological temperatures.