Effect of Covalence and Degree of Cation Order on the Luminous Efficacy of Mn4+ Luminescence in the Double Perovskites, Ba2B TaO6 (B = Y, Lu, Sc)

Alok M Srivastava; Mikhail G Brik; Chong-Geng Ma; William W Beers; William E Cohen; Michal Piasecki

doi:10.1021/acs.jpclett.4c00205

Effect of Covalence and Degree of Cation Order on the Luminous Efficacy of Mn⁴⁺ Luminescence in the Double Perovskites, Ba₂B TaO₆ (B = Y, Lu, Sc)

J Phys Chem Lett. 2024 Apr 18;15(15):4175-4184. doi: 10.1021/acs.jpclett.4c00205. Epub 2024 Apr 10.

Authors

Alok M Srivastava¹, Mikhail G Brik^{2

3

4

5}, Chong-Geng Ma², William W Beers¹, William E Cohen¹, Michal Piasecki⁶

Affiliations

¹ Current Chemicals, 1099 Ivanhoe Road, Cleveland, Ohio 44110, United States.
² School of Optoelectronic Engineering & CQUPT-BUL Innovation Institute, Chongqing University of Posts and Telecommunications, Chongqing 400065, PR China.
³ Center of Excellence for Photoconversion, Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, Belgrade 11351, Serbia.
⁴ Institute of Physics, University of Tartu, W. Ostwald Str. 1, Tartu 50411, Estonia.
⁵ Academy of Romanian Scientists, Ilfov Str. No. 3, Bucharest 050663, Romania.
⁶ Faculty of Science and Technology, Jan Długosz University, Armii Krajowej 13/15, Czestochowa 42200, Poland.

Abstract

The spectroscopic properties of the Mn⁴⁺ ion are investigated in the series of isostructural double perovskite compounds, Ba₂BTaO₆ (B = Y, Lu, Sc). A comparison of these properties highlights the influence of covalent bonding within the perovskite framework and the degree of order between the B³⁺-Ta cations on the energy and intensity of the Mn⁴⁺²E → ⁴A₂ emission transition (R-line). These two parameters of the emission spectrum are of importance for practical application since they determine the phosphor luminous efficacy. The influence of covalent bonding within the corner shared BO_6/2 and TaO_6/2 perovskite framework on the energy of the R-line energy is investigated. From the spectroscopic data, we have derived information on the influence of the degree of order between the B³⁺ and Ta⁵⁺ cations on the intensity of the R-line. The lowest energy and the highest intensity of the R-line are found in the double perovskite, Ba₂ScTaO₆. The purpose of this work is to propose for first time an explanation of these effects in the considered double perovskites. The obtained results are useful guidelines for practical improvement and tuning of key parameters of phosphors to the desired values.