Intense deep-red zero phonon line emission of Mn4+ in double perovskite La4Ti3O12

Haipeng Ji; Jumpei Ueda; Mikhail G Brik; Mao-Hua Du; Deliang Chen; Setsuhisa Tanabe

doi:10.1039/c9cp04007b

Intense deep-red zero phonon line emission of Mn⁴⁺ in double perovskite La₄Ti₃O₁₂

Phys Chem Chem Phys. 2019 Dec 7;21(45):25108-25117. doi: 10.1039/c9cp04007b. Epub 2019 Nov 6.

Authors

Haipeng Ji¹, Jumpei Ueda², Mikhail G Brik³, Mao-Hua Du⁴, Deliang Chen⁵, Setsuhisa Tanabe²

Affiliations

¹ School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China. jihp@zzu.edu.cn dlchen@zzu.edu.cn and Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan.
² Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan.
³ College of Sciences, Chongqing University of Posts and Telecommunications, Chongqing 400065, China and Institute of Physics, University of Tartu, Tartu 50411, Estonia.
⁴ Materials Science & Technology Division, Oak Ridge, TN 37831, USA.
⁵ School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China. jihp@zzu.edu.cn dlchen@zzu.edu.cn.

PMID: 31691694
DOI: 10.1039/c9cp04007b

Abstract

Phosphors that emit in the deep-red spectral region are critical for plant cultivation light-emitting diodes. Herein, ultrabroadband deep-red luminescence of Mn⁴⁺ in La₄Ti₃O₁₂ was studied, which showed intense zero phonon line emission. The double-perovskite structural La₄Ti₃O₁₂ simultaneously contains two Ti⁴⁺ sites forming slightly- and highly-distorted TiO₆ octahedra, respectively. The influence of octahedral distortion on the Mn⁴⁺ emission energy in the two distinct Ti⁴⁺ sites was studied both experimentally and theoretically. The spectral measurements indicated that Mn⁴⁺ in La₄Ti₃O₁₂ showed intense zero phonon line emission (ZPL) at deep-red 710-740 nm under excitation of 400 nm charging the O^2-→ Mn⁴⁺ charge transfer transition. The splitting of the ZPL of the Mn^{4+ 2}E_g→⁴A_2g transition as well as the intensity of ZPL relative to the vibronic phonon sideband emissions were found to be greatly influenced by the degree of octahedral distortion. The crystal-field strength and Racah parameters of Mn⁴⁺ in each Ti⁴⁺ site were also estimated. The Mn^{4+ 2}E_g→⁴A_2g luminescence exhibited severe thermal quenching, which was explained by the low-lying ⁴T_2g level and charge-transfer state.