An insight into local environment of lanthanide ions in Sr2SiO4:Ln (Ln = Sm, Eu and Dy)

Sr2SiO4 is an important inorganic host for lanthanide-doped white-light-emitting diodes. In order to probe the local structure and symmetry around lanthanide ions in Sr2SiO4, detailed experimental and theoretical investigations have been carried out. Samples prepared via sol–gel methods were thoroughly characterized using X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS) and photoluminescence (PL) spectroscopy. The local symmetries of SrO9 and SrO10 polyhedra were determined using emission spectroscopy with europium as the probe ion. Despite having the same oxidation state and comparable ionic radii, Sm3+, Dy3+ and Eu3+ behave differently in terms of their site occupation at the Sr sites of SrO9 and SrO10 polyhedra. While Eu replaces Sr in both polyhedra, Sm and Dy reside specifically at the 9-coordinated Sr sites only. Based on density functional theory (DFT) calculations, it has been established that for Dy and Sm, the strong metal–oxygen bonding leads to significant distortion and hence the destabilization of MO10 polyhedra in the host.

[1]  S. Gupta,et al.  Local site symmetry of Sm3+ in sol–gel derived α′-Sr2SiO4: Probed by emission and fluorescence lifetime spectroscopy , 2016 .

[2]  S. Gupta,et al.  Nanorods of white light emitting Sr2SiO4:Eu2+: microemulsion-based synthesis, EPR, photoluminescence, and thermoluminescence studies , 2015 .

[3]  J. Barzowska,et al.  Dosimetric features of strontium orthosilicate (Sr2SiO4) doped with Eu2 , 2014 .

[4]  S. Duan,et al.  Thermochromic material Sr2SiO4:Eu2+ based on displacive transformation , 2014 .

[5]  J. Qiu,et al.  Color variation of photo-stimulated luminescence in strontium ortho-silicate with the assistance of trap centers , 2014 .

[6]  S. C. Sharma,et al.  Study on low temperature solution combustion synthesized Sr(2)SiO(4):Dy(3+) nano phosphor for white LED. , 2014, Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy.

[7]  S. C. Sharma,et al.  Enhanced luminescence by monovalent alkali metal ions in Sr2SiO4:Eu3+ nanophosphor prepared by low temperature solution combustion method , 2014 .

[8]  H. Swart,et al.  TOF SIMS analysis and generation of white photoluminescence from strontium silicate codoped with europium and terbium , 2014 .

[9]  S. Gupta,et al.  Optical properties of sol–gel derived Sr2SiO4:Dy3+ – Photo and thermally stimulated luminescence , 2013 .

[10]  S. Mishra,et al.  Characterization of Sb-doped Bi(2)UO(6) solid solutions by X-ray diffraction and X-ray absorption spectroscopy. , 2013, Analytical sciences : the international journal of the Japan Society for Analytical Chemistry.

[11]  D. Patel,et al.  Probing local environments in Eu3+ doped SrSnO3 nano-rods by luminescence and Sr K-edge EXAFS techniques , 2013 .

[12]  D. Bhattacharyya,et al.  Extended X-ray absorption fine structure study of Gd doped ZrO2 systems , 2013 .

[13]  Yingliang Liu,et al.  Temperature-Dependent Long-Lasting Phosphorescence in SrSi2O2N2:Eu2+ , 2013 .

[14]  S. Gupta,et al.  Structure and site selective luminescence of sol–gel derived Eu:Sr2SiO4 , 2012 .

[15]  S. Mho,et al.  Identification of Two Luminescence Sites of Sr2SiO4:Eu2+ and (Sr,Ba)2SiO4:Eu2+ Phosphors , 2010 .

[16]  Yongsheng Liu,et al.  Optical Spectroscopy of Eu3+ Doped ZnO Nanocrystals , 2009 .

[17]  Yongjun Zhang,et al.  Luminescence behavior of Eu3+ in CaSiO3:Eu3+(Bi3+) and Sr2SiO4:Eu3+(Bi3+) , 2008 .

[18]  U. Varadaraju,et al.  White-Light Generation in Sr2SiO4 : Eu2 + , Ce3 + under Near-UV Excitation A Novel Phosphor for Solid-State Lighting , 2005 .

[19]  X. Y. Chen,et al.  The standard and anomalous crystal-field spectra of Eu3+ , 2005 .

[20]  X. Y. Chen,et al.  Anomalous luminescence dynamics of Eu3+ in BaFCl microcrystals , 2004 .

[21]  Abanti Nag,et al.  The light induced valence change of europium in Sr2SiO4∶ Eu involving transient crystal structure , 2004 .

[22]  Hee Dong Park,et al.  White light-emitting diodes of GaN-based Sr2SiO4:Eu and the luminescent properties , 2003 .

[23]  E. Stern,et al.  Analysis of multiple-scattering XAFS data using theoretical standards , 1995 .

[24]  D. Koningsberger,et al.  X-ray absorption : principles, applications, techniques of EXAFS, SEXAFS and XANES , 1988 .

[25]  M. Catti,et al.  Structures of twinned -Sr2SiO4 and of a'-Sr1.9Ba0.1SiO4 , 1983 .

[26]  M. Catti,et al.  β‐Sr2SiO4双晶およびα′‐Sr1.9Ba0.1SiO4の構造 , 1983 .

[27]  R. D. Shannon.  Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides , 1976 .