JOURNAL OF RARE EARTHS, Vol. 27, No. 4, Aug. 2009, p. 544 Foundation item: Project partially supported by the Institute of Physical Chemistry of the Polish Academy of Sciences Corresponding author: Renata Reisfeld (E-mail: renata@vms.huji.ac.il; Tel.: 972-2-6585323) DOI: 10.1016/S1002-0721(08)60285-9 Luminescence intensification of lanthanide complexes by silver nanoparticles incorporated in sol-gel matrix Renata Reisfeld 1 , Marek Pietraszkiewicz 2 , Tsiala Saraidarov 1 , Viktoria Levchenko 1 (1. Inorganic Chemistry Department, The Hebrew University of Jerusalem, Givat-Ram, 91940 Jerusalem, Israel; 2.Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland) Received 17 September 2008; revised 20 December 2008 Abstract: We present how the luminescence of europium RR-2-P-oxides complexes can be increased by interaction of electronic levels of the complex with the radiation field of silver nanoparticles (NPs). The procedure by which silver NPs are formed in a sol-gel polyurethane matrix precursor was elaborated. The formed Ag NPs were combined with Eu complex incorporated in ormocer matrix. The emission spectra of the complexes without silver NPs were compared with spectra of the same complexes with addition of silver NPs. As the result of the in- teraction of the electronic levels of lanthanide ligands with silver plasmons dramatic increase of luminescence was observed. Keywords: luminescence intensification; Eu RR-2-P-oxides complexes; silver nanoparticles; silica-polyurethane; zirconia-glymo; particles size distribution; rare earths It is well established that the weak luminescence of lan- thanides arising from Laporte forbidden f-f transition can be strongly enhanced by preparing a complex with strong light-absorbing ligand followed by energy transfer from the ligand to the lanthanide ion [1] . Such complexes could be seen as light conversion molecular devices (LCMDs), coin- ing the term “antenna effect” to donate the absorption, en- ergy-transfer, emission sequence involving distinct absorb- ing (the ligand) and emitting (the lanthanide ion) compo- nents, thus overcoming the very small absorption coeffi- cients of the lanthanide ions. The design of efficient lantha- nide complexes has become an important research goal. The interest in the photophysical properties of lanthanide ion complexes has grown considerably since Lehn [2] proposed the system then being pursued by several groups, working with many different classes of ligands (e.g. cryptands, po- dandts, calixarenes, macrocyclic ligands, 1,3-diketones, het- erobiaryl ligands, carboxylic acid derivatives, terphenyl ligands, proteins, etc.) [3–5] . Most of complexes investigated emit red or green light (Eu(III)ţ and Tb(III)ţ luminescence, respectively). Efficient LCMDs may find several applica- tions, such as luminescent probes in biomedical assays and time resolved microscopy, fluorescent lighting and lumi- nescent sensors for chemical species (Hţ, O 2 , halide ions, OH), electroluminescent devices, UV dosimeters. It was shown previously that lanthanide complexes in- corporated into sol-gel glasses have superior optical proper- ties. Silicon inorganic and organic-inorganic hybrids, syn- thesized through sol-gel process could be used to produce silica glasses with trapped Tb +3 and Eu +3 fluorescent com- pounds. Silicon hybrids have, as advantage, their very low solubility in water and in many polar and non-polar solvents, as well as their high thermal stability [6,7] . It has been shown that organic complexes of rare earths doped in zirconia and zirconia-GLYMO had much higher fluorescence then in pure inorganic matrices. Recently we showed an increase of luminescence emission intensity of the complexed Tb 3+ and Eu 3+ ions incorporated in sol-gel based zirconia ormocer films as a result of energy transfer from the ligands to the RE ions [8–10] . The matrix chosen in this work possesses high mechanical and thermal stability and a high refractive index due to the component zirconium oxide. In this paper we show an appreciate increase of lumines- cence of lanthanide complex in the presence of silver nanoparticles (plasmons) as compared to the luminescence of the same complex without silver plasmons. This phe- nomenon observed is the result of interaction of the complex with silver plasmons. It is known that metal nanoparticles can result in strong scattering of incident light and greatly enhanced local fields, and can also lead to enhanced Raman scattering. Surface plasmons are collective oscillations of the electrons of conductors, and have attracted intense inter- PDF 文件使用 " pdf Fact or y Pr o" 试用版本创建 www. f i nepri nt . cn