Optical behaviors of Mn4+-modified cubic type ZnTiO3:Eu3+ nanocrystals: Application in optical thermometers based on fluorescence intensity ratio and lifetime

Fengya Hu; Dong Zhang; Yongjin Wu; Chengmei Sun; Chengcheng Xu; Qingru Wang; Yanru Xie; Qiang Shi; Shuhong Li; Kai Wang

doi:10.1016/j.saa.2023.123339

Optical behaviors of Mn⁴⁺-modified cubic type ZnTiO₃:Eu³⁺ nanocrystals: Application in optical thermometers based on fluorescence intensity ratio and lifetime

Spectrochim Acta A Mol Biomol Spectrosc. 2024 Jan 5:304:123339. doi: 10.1016/j.saa.2023.123339. Epub 2023 Sep 1.

Authors

Fengya Hu¹, Dong Zhang², Yongjin Wu¹, Chengmei Sun¹, Chengcheng Xu¹, Qingru Wang³, Yanru Xie¹, Qiang Shi¹, Shuhong Li¹, Kai Wang¹

Affiliations

¹ School of Physical Science and Information Technology, Shandong Key Lab. of Optical Communication Science and Technology, Liaocheng University, Liaocheng 252059, China.
² School of Physical Science and Information Technology, Shandong Key Lab. of Optical Communication Science and Technology, Liaocheng University, Liaocheng 252059, China. Electronic address: zhangdong@lcu.edu.cn.
³ School of Physical Science and Information Technology, Shandong Key Lab. of Optical Communication Science and Technology, Liaocheng University, Liaocheng 252059, China. Electronic address: wangqingru@lcu.edu.cn.

PMID: 37683437
DOI: 10.1016/j.saa.2023.123339

Abstract

Cubic type ZnTiO₃ nanophosphors were fabricated by using hydrothermal method. The photoluminescence behaviors of Eu³⁺/Mn⁴⁺ co-doped ZnTiO₃ crystals and Mn⁴⁺-modified ZnTiO₃:Eu³⁺ crystals were investigated. The red and near-infrared emissions assigned to Eu³⁺ and Mn⁴⁺ were observed at the excitation wavelength of 465 nm for Eu³⁺/Mn⁴⁺ co-doped ZnTiO₃ crystals and Mn⁴⁺ modified ZnTiO₃:Eu³⁺ crystals. Eu³⁺/Mn⁴⁺ co-doped ZnTiO₃ crystals revealed the most intense near-infrared emission assigned to Mn⁴⁺. For Mn⁴⁺-modified ZnTiO₃:Eu³⁺ crystals, the red emissions assigned to Mn⁴⁺ revealed an obvious enhancement with the concentration of Mn⁴⁺ increasing from 0.01 mol% to 0.1 mol%, and then revealed a concentration quenching behavior at the Mn⁴⁺ concentration of 0.5 mol% and 1 mol%. Under 465 nm excitation wavelength, the emission assigned to ²E_g → ⁴A_2g of Mn⁴⁺ in ZnTiO₃ revealed stronger temperature dependence compared with that assigned to ⁵D₀ → ⁷F₂ transition of Eu³⁺. Based on the fluorescence intensity ratio between Eu³⁺ and Mn⁴⁺, the maximum relative sensitivity of 3.15 %/K at 305 K for the 0.05 mol% Mn⁴⁺ modified ZnTiO₃:Eu³⁺ was achieved, which was higher than that of 2.9 %/K for Eu³⁺/Mn⁴⁺ co-doping ZnTiO₃ nanocrystals. Based on the lifetime of the emission of Mn⁴⁺, the highest relative sensitivity of 1.4 %/K was obtained in the 0.05 mol% Mn⁴⁺ modified ZnTiO₃:Eu³⁺, which was lower than that based on fluorescence intensity ratio. It indicated that the surface modification by transition metals should improve the temperatures sensing performance and had potential applications in optical thermometers.

Keywords: Cubic ZnTiO(3); Fluorescence intensity ratio; Optical thermometry; Photoluminescence.