title: Luminescence Properties of SrZrO3/Tb(3+) Perovskite: Host-Dopant Energy-Transfer Dynamics and Local Structure of Tb(3+).
abstract: SrZrO3 perovskite (SZP) was synthesized using gel-combustion route and characterized systematically using X-ray diffraction and time-resolved photoluminescence techniques. A detailed analysis of the optical properties of Tb(3+) ions in SrZrO3 was performed to correlate them with the local environment of the lanthanide ions in this perovskite. Photoluminescence (PL) spectroscopy showed that emission spectrum consists of host as well as Tb(3+) emission indicating the absence of complete host-dopant energy transfer. On the basis of emission spectrum and PL decay study it was also observed that Tb(3+) is not homogeneously distributed in SrZrO3 perovskite; rather, it is occupying two different sites. It is corroborated using extended X-ray absorption fine structure studies that Tb(3+) is stabilized on both six-coordinated Zr(4+) and eight-coordinated Sr(2) site. The energies calculated using density functional theory (DFT) indicates that Tb occupation in Sr site is energetically more favorable than Zr site. The analysis of valence charge distribution also substantiated our structural stability analysis of site-selective Tb doping in SrZrO3. Time-resolved emission spectroscopy is employed to elucidate the difference in the spectral feature of Tb(3+) ion at Sr(2+) and Zr(4+) site. DFT-calculated density of states analysis showed that energy mismatch of Tb-d states with Zr-d and O-p states of SZP makes the energy transfer from host SZP to Tb(3+) ion difficult.
authors.affiliation: Radiochemistry Division, ‡Materials Science Division, and §Atomic and Molecular Physics Division, Bhabha Atomic Research Centre , Trombay Mumbai 400085, India.
authors.forename: Santosh Kumar
authors.initials: SK
authors.lastname: Gupta
authors.affiliation: Radiochemistry Division, ‡Materials Science Division, and §Atomic and Molecular Physics Division, Bhabha Atomic Research Centre , Trombay Mumbai 400085, India.
authors.forename: Partha Sarathi
authors.initials: PS
authors.lastname: Ghosh
authors.affiliation: Radiochemistry Division, ‡Materials Science Division, and §Atomic and Molecular Physics Division, Bhabha Atomic Research Centre , Trombay Mumbai 400085, India.
authors.forename: Ashok Kumar
authors.initials: AK
authors.lastname: Yadav
authors.affiliation: Radiochemistry Division, ‡Materials Science Division, and §Atomic and Molecular Physics Division, Bhabha Atomic Research Centre , Trombay Mumbai 400085, India.
authors.forename: Nimai
authors.initials: N
authors.lastname: Pathak
authors.affiliation: Radiochemistry Division, ‡Materials Science Division, and §Atomic and Molecular Physics Division, Bhabha Atomic Research Centre , Trombay Mumbai 400085, India.
authors.forename: Ashok
authors.initials: A
authors.lastname: Arya
authors.affiliation: Radiochemistry Division, ‡Materials Science Division, and §Atomic and Molecular Physics Division, Bhabha Atomic Research Centre , Trombay Mumbai 400085, India.
authors.forename: Shambhu Nath
authors.initials: SN
authors.lastname: Jha
authors.affiliation: Radiochemistry Division, ‡Materials Science Division, and §Atomic and Molecular Physics Division, Bhabha Atomic Research Centre , Trombay Mumbai 400085, India.
authors.forename: Dibyendu
authors.initials: D
authors.lastname: Bhattacharyya
authors.affiliation: Radiochemistry Division, ‡Materials Science Division, and §Atomic and Molecular Physics Division, Bhabha Atomic Research Centre , Trombay Mumbai 400085, India.
authors.forename: Ramakant Mahadeo
authors.initials: RM
authors.lastname: Kadam