Chemical Pressure Effects on the Stokes Shift of Bi3+ Luminescence in Orthorhombic Perovskites. (1st September 2022)

• Record Type: Journal Article
• Authors: Srivastava, A. M.; Brik, M. G.; Beers, W. W.; Cohen, W.
• Is Part Of: ECS journal of solid state science and technology. Volume 11:Number 9(2022)
• Publication Date: 2022-09-01
• Subjects: Luminescence -- Luminescence - Processes -- Luminescence - Other Activators; Solid state chemistry -- Periodicals; Electronics -- Materials -- Periodicals; Electrochemistry -- Periodicals; 541.0421
• DOI: 10.1149/2162-8777/ac915b
• Languages: English
• ISSNs: 2162-8777

Abstract

Abstract : The relationship between the Stokes shift of Bi 3+ emission and the volume of the unit-cell in two series of orthorhombic perovskites, Ln B 3+ O3 (Ln = La, Gd, Y; B 3+ = Al, In, Ga) and A B 4+ O3 (A = Ca, Sr; B 4+ = Zr, Sn) is explored. The Stokes shift increases linearly with increasing cell volume. This is explained qualitatively by the lattice chemical pressure acting on the Bi 3+ ion. The degree of Bi 3+ ion off-centering displacement, which is due to the stereochemical activity of the lone-pair electrons (6 s 2 ), is controlled by the chemical pressure. A small cell suppresses the off-centering displacement to produce a small Stokes shift of emission by limiting the excited state structural distortion. In large cell, the off-centering displacement is more easily accommodated. The elimination of ground state distortion in the excited state gives larger Stokes shift of emission. These qualitative arguments are supplemented by recent first-principles calculations on Bi 3+ luminescence in these perovskites. The Bi 3+ luminescence in SrZrO3, previously assigned to emission from the D-state, is now assigned to the localized 3 P0, 1 → 1 S0 transition. The energy of the 1 S0 → 3 P1 transition is correlated with the covalence of the B O6/2 perovskite framework. Discussion on the effective ionic radius of the Bi 3+ ion in these perovskites is presented.