Home Search Collections Journals About Contact us My IOPscience Synthesis, characterization and luminescent properties of Tb(III) doped Eu(III) complex nanoparticles This content has been downloaded from IOPscience Please scroll down to see the full text 2011 Adv Nat Sci: Nanosci Nanotechnol 025015 (http://iopscience.iop.org/2043-6262/2/2/025015) View the table of contents for this issue, or go to the journal homepage for more Download details: IP Address: 80.82.77.83 This content was downloaded on 11/04/2017 at 09:20 Please note that terms and conditions apply You may also be interested in: Synthesis and characterization of europium(III) nanoparticles for time-resolvedfluoroimmunoassay of prostate-specific antigen Harri Härmä, Anne-Maria Keränen and Timo Lövgren Development of a fluorescent label tool based on lanthanide nanophosphors for viral biomedical application Quoc Minh Le, Thu Huong Tran, Thanh Huong Nguyen et al Coating multi-walled carbon nanotubes with rare-earth complexes 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doped Eu(III) complex nanoparticles Thi Khuyen Hoang1 , Thanh Huong Nguyen1 , Thu Huong Tran1 , Kim Anh Tran1 , Thanh Binh Nguyen1 and Quoc Minh Le1,2 Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay Dist, Hanoi, Vietnam University of Engineering and Technology, Vietnam National University, 144 Xuan Thuy Road, Cau Giay Dist, Hanoi, Vietnam E-mail: khuyenht@ims.vast.ac.vn Received 15 October 2010 Accepted for publication 19 April 2011 Published 10 June 2011 Online at stacks.iop.org/ANSN/2/025015 Abstract In recent years, considerable effort has been devoted to the development of transition metal complexes as novel luminescent materials that have potential application in the fluorescent labels for chemistry or biology Among them, the nanostructured lanthanide complexes have been receiving much attention because of their excellent luminescence properties, which are attributed to the intramolecular energy transfer between the ligands and chelated lanthanide ions and their high solubility in water This paper presents some results of the synthesis and characterization of the nanoparticles of Eu(III) and Tb(III) complexes with naphthoyl trifluoroacetone and tri-n-octylphosphineoxide In addition, the influence of the dopant Tb(III) on the photophysical properties of the system of lanthanide complexes of Eu(III) and Tb(III) is also studied Keywords: lanthanide complexes, nanoparticles, luminescence, fluorescent labels Classification number: 4.02 lifetime (sub-microsecond to millisecond range), sharply spiky emission spectra (150 nm), and high quantum yield (∼1) [9, 10] In this study, the nanostructured Tb(III) doped Eu(III) complexes with tri-n-octylphosphineoxide and naphthoyl trifluoroacetone ligands were synthesized and their characterization and spectral properties, such as fluorescence intensity, emission spectrum and fluorescence lifetime, were studied in detail Introduction Various luminescent nanoparticle materials have recently been fabricated and applied in diagnostics, high throughput screening, and bioimaging [1–4] The use of fluorescent nanoparticle labels in highly sensitive assays is based on their optical properties [5–8] The lanthanide chelate labels in biological studies contain typically an organic chromophore, which sensitizes to absorb the excitation light and transfer the excitation energy to the lanthanide ions Consequently, lanthanide chelates exhibit broad excitation spectra owing to the organic ligands and narrow emission spectra resulting from the lanthanide ions Recently, their application to biological labeling has attracted growing interest due to their high photochemical stability and quantum yield, and their good water solubility, and because they possess a reactive group that allows covalent attachment to biomolecules The spectral characteristics include a long fluorescence 2043-6262/11/025015+04$33.00 Experimental 2.1 Materials EuCl3 · 6H2 O (99,99%), TbCl3 · 6H2 O (99,99%), tri-n-octylphosphineoxide (TOPO) and 1-(2-naphthoyl)-3,3, 3-trifluoroacetone (NTA) were purchased from Sigma Aldrich Sodium dodecyl sulfate (SDS), dimethyl sulfoxide © 2011 Vietnam Academy of Science & Technology Content from this work may be used under the terms of the Creative Commons Attribution-NonCommercial ShareAlike 3.0 licence Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI Adv Nat Sci.: Nanosci Nanotechnol (2011) 025015 T K Hoang et al Table The ratios of Eu(III) complex solution and Tb(III) complex solution Sample MEu Ratio Tb/Eu 100% Eu (a) MTbEu1a MTbEu2a MTbEu3a MTbEu4a 16/1 8/1 4/1 1/1 (b) Figure Structure of lanthanide chelates with NTA and TOPO ligands (DMSO), dimethyl formamide (DMF) and polyvinylpyrrolidone (PVP) (M = 40 000 g mol−1 ) were from Merck Deionised water was used for the preparation of nanoparticle solutions All other chemicals were of analytical grade Figure FESEM images of the fluorescent nanoparticles of (a) Tb(III) doped Eu(III): NTA.TOPO and (b) Tb(III) doped Eu(III): NTA.TOPO@PVP 2.2 Synthesis spectrophotometer system (Horiba Jobin Yvon IHR 550) Fourier transform infrared (FTIR) spectra of the nanoparticles were measured by using an IMPACT 410-Nicolet (FTIR) spectrometer Eu(III) complex solution was prepared from 50 mg EuCl3 · 6H2 O, 135 mg TOPO and 125 mg NTA in 40 ml DMSO Tb(III) complex solution was formed from 60 mg TbCl3 · 6H2 O, 160 mg TOPO and 125 mg NTA in 40 ml DMSO Eu(III) complex and Tb(III) complex solutions were mixed with the ratios in table The fabrication of the nanostructured particles of lanthanide complexes was carried out using a vortex mixer (Labinco L46, Netherlands) The reaction tube containing ml of water was stirred at 500 rpm and a mixture of 0.25 ml Tb(III) doped Eu(III) complex solution and 0.1 ml SDS 10 mM was rapidly added to the tube using a maximum vortex mixing speed of 2500 rpm The reactions were carried out at room temperature A colloidal solution of Tb(III) doped Eu(III) nanoparticles was produced by agglomerating hydrophobic chelates in aqueous solution After agglomeration, 0.1 ml PVP was added into the solution A PVP shell was subsequently grown onto the agglomerated nanoparticles (figure 1) The morphology and size of the nanoparticles were determined by using a field emission scanning electron microscope (FESEM, Hitachi, S-4800) The emission (fluorescence) spectra were recorded on a luminescence Results and discussion In this research, uniform fluorescent nanoparticles were synthesized in one step at room temperature Figure shows FESEM images of synthesized nanoparticles of Tb(III) doped Eu(III) chelate with TOPO and NTA ligands Aggregation of nanoparticles is not observed The obtained nanosized particles were uniform with a mean diameter of 25 nm ± nm and shell thickness of 10 nm The FTIR spectra of the synthesized nanoparticles of Tb(III) doped Eu(III) chelates are given in figure A broad band at wavenumber of 3444 cm−1 is attributed to the H2 O molecule, and the band at 1650 cm−1 is related to the C = O group of the ligand The complexation between Eu(III) and Tb(III) with NTA.TOPO ligands is evidenced by a narrow band located at 1388 cm−1 , which appeared to prove that Eu(III) or Tb(III) ions may be coordinated to two oxygen atoms of ligands Adv Nat Sci.: Nanosci Nanotechnol (2011) 025015 T K Hoang et al 1.0 3444.64 Tbeu3a_01 Date : Fri Sep 2010 Scans : 32 Resolution : 4000 Absorbance 0.8 0.6 1649.92 0.4 493.15 1107.97 0.2 1018.95 1434.21 1388.37 1253.55 768.18 671.11 598.31 0.0 4000 3500 3000 2500 2000 1500 1000 500 -1 wavenumbers (cm ) Figure The Fourier transform infrared (FTIR) spectra of nanoparticles of Tb(III) doped Eu(III): NTA.TOPO@PVP 6000 250 616nm MEu 5000 D 0- F MEu MTbEu4a MTbEu3a 200 MTbEu3a Intensity (au) Intensity 4000 3000 2000 5 MEu 100 MTbEu4a D 0- F 1000 150 5 D0- F0 D0- F3 50 D0- F4 500 550 600 650 700 750 800 850 wavelength (nm) Time (ms) Figure Fluorescent spectra of nanoparticles of Eu(III): NTA.TOPO@PVP at λexc = 370 nm Figure Emission lifetime of nanoparticles of Tb(III) doped Eu(III): NTA.TOPO@PVP at λexc = 325 nm 7000 MTbEu4a MTb MTbEu1a MTbEu2a MTbEu3a MTbEu4a MEu 6000 5000 Intensity 4000 Emission spectra of nanostructured Eu(III) chelates and Tb(III) doped Eu(III) chelates in aqueous solution were measured under excitation of λexc = 325 nm and λexc = 370 nm It can be seen that the nanoparticle complexes exhibit the characteristic narrow emission peaks of trivalent lanthanide ions The Eu(III) nanoparticles showed a maximum emission at 616 nm (figure 4) The emission spectra consist of four main peaks at 593, 616, 652 and 702 nm, which correspond to the D0 →7 Fn (n = 1, 2, 3, 4) transitions of Eu(III) (5 D0 →7F1 at 593 nm, D0 →7F2 at 616 nm, D0 →7F3 at 652 nm and D4 →7F4 at 702 nm) The influence of the dopant to optical properties of the nanoparticle complexes of Tb(III) doped Eu(III) was investigated The shape of the spectra of samples of nanoparticle Tb(III) doped Eu(III) chelates is similar in the case of Eu(III) nanoparticles and the emission maximum is not MEu MTbEu3a MTbEu2a 3000 MTbEu1a 2000 MTb 1000 350 400 450 500 550 600 650 700 750 800 wavelength(nm) Figure Fluorescent spectra of nanoparticles of Tb(III) doped Eu(III): NTA.TOPO@PVP at λexc = 325 nm Adv Nat Sci.: Nanosci Nanotechnol (2011) 025015 T K Hoang et al shifted However, the fluorescent intensity of nanoparticles in aqueous solution depends strongly on the ratio of Tb(III) in Eu(III) chelates (figure 5) In the studied range of ratios, the intensity at the peak of 616 nm of sample MTbEu4a with ratio (1 : 1) is higher than that of MEu The fluorescence lifetime of nanosized complex samples MTbEu4a, MEu, and MTbEu3a was found to be 587, 566 and 431 µs, respectively (figure 6) Acknowledgments This work was supported by the Vietnam Basic Research Programming for application, project 2/2/742/2009/HÐÐTÐL, Vietnam’s National Foundation for Science and Technology Development (NAFOSTED), project code: 103.06.46.09 and The Key Lab of Electronic Materials and Devices The authors acknowledge all the members of FESEM and PL groups for their technical assistance Conclusions References The nanostructured particles of Tb(III) doped Eu(III) chelate with TOPO and NTA ligands were successfully synthesized The uniform nanoparticles can be synthesized at room temperature without rigorous experimental conditions These nanoparticles Tb(III) doped Eu(III) chelates are stable in aqueous solution, which was obtained by adsorbing PVP on their surface The aggregation of the nanoparticles is prevented, which is a result of the presence of a protective polymer layer A nanoparticle size of 25 nm ± nm and a shell thickness of 10 nm were obtained The nanoparticle complexes exhibit the characteristic narrow emission peaks and maximum emission at 616 nm The fluorescent intensity of nanoparticles in aqueous solution depends on the ratio of Tb(III) in Eu(III) chelates The fluorescence lifetime of synthesized nanoparticle chelates was approximately 550 µs [1] Patra C R, Bhattacharya R, Patra S, Basu S, Mukherjee P and Mukhopadhyay D 2006 J Nanobiotechnol 11 [2] Yuan J and Wang G 2005 J Fluoresc 15 559 [3] Lam Thi K G, Opalinska A, Chudoba T, Benkowski K, Lojkowski W, Tran K A, Nguyen T B and Le Quoc M 2010 Adv Nat Sci.: Nanosci Nanotechnol 025007 [4] Steinkamp T and Karst U 2004 Anal Bioanal Chem 380 24 [5] Tran T H, Tran K A and Le Quoc M 2009 J Phys.: Conf Ser 187 012064 [6] Medintz I L, Uyeda H T, Goldman E R and Mattoussi H 2005 Nat Mater 435 [7] Hemmila I and Laitala V 2005 J Fluoresc 15 529 [8] Harma H, Graf C and Hanninen P 2008 J Nanopart Res 10 1221 [9] Wang F, Tan W B, Zhang Y, Fan X and Wang M 2006 Nanotechnology 17 R1 [10] Li M and Selvin P R 1997 Bioconjug Chem 127 ... influence of the dopant to optical properties of the nanoparticle complexes of Tb(III) doped Eu(III) was investigated The shape of the spectra of samples of nanoparticle Tb(III) doped Eu(III) chelates... related to the C = O group of the ligand The complexation between Eu(III) and Tb(III) with NTA.TOPO ligands is evidenced by a narrow band located at 1388 cm−1 , which appeared to prove that Eu(III). .. spectra of the synthesized nanoparticles of Tb(III) doped Eu(III) chelates are given in figure A broad band at wavenumber of 3444 cm−1 is attributed to the H2 O molecule, and the band at 1650