Sensitive and Reliable Fluorescent Thermometer Based on a Red-Emitting Li2MgHfO4:Mn4+ Phosphor

Yonghong Qin; Fen Zhong; Yinan Bian; Shruti Hariyani; Yaxin Cao; Jakoah Brgoch; Takatoshi Seto; Mikhail G Brik; Alok M Srivastava; Xicheng Wang; Yuhua Wang

doi:10.1021/acs.inorgchem.1c03971

Sensitive and Reliable Fluorescent Thermometer Based on a Red-Emitting Li₂MgHfO₄:Mn⁴⁺ Phosphor

Inorg Chem. 2022 May 30;61(21):8126-8134. doi: 10.1021/acs.inorgchem.1c03971. Epub 2022 Apr 5.

Authors

Yonghong Qin^{1

2

3}, Fen Zhong^{1

2

3}, Yinan Bian^{1

2

3}, Shruti Hariyani⁴, Yaxin Cao^{1

2

3}, Jakoah Brgoch⁴, Takatoshi Seto¹, Mikhail G Brik^{5

6

7

8}, Alok M Srivastava⁹, Xicheng Wang^{1

2

3}, Yuhua Wang^{1

2

3}

Affiliations

¹ School of Materials and Energy, Lanzhou University, Lanzhou 730000, China.
² National & Local Joint Engineering Laboratory for Optical Conversion Materials and Technology, Lanzhou University, Lanzhou 730000, China.
³ Key Laboratory for Special Function Materials and Structural Design of the Ministry of the Education, Lanzhou University, Lanzhou 730000, China.
⁴ Department of Chemistry, University of Houston, Houston, 77204 Texas, United States.
⁵ College of Sciences & CQUPT-BUL Innovation Institute, Chongqing University of Posts and Telecommunications, Chongqing 400065, People's Republic of China.
⁶ Institute of Physics, University of Tartu, W. Ostwald Street 1, Tartu 50411, Estonia.
⁷ Institute of Physics, Jan Długosz University, Armii Krajowej 13/15, PL-42200 Częstochowa, Poland.
⁸ Academy of Romanian Scientists, Ilfov Street, no 3, 050044 Bucharest, Romania.
⁹ Current Lighting Solutions, LLC, 1099 Ivanhoe Road, Cleveland, Ohio 44110, United States.

PMID: 35381177
DOI: 10.1021/acs.inorgchem.1c03971

Abstract

Contactless fluorescent thermometers are rapidly gaining popularity due to their sensitivity and flexibility. However, the development of sensitive and reliable non-rare-earth-containing fluorescent thermometers remains a significant challenge. Here, a new rare-earth-free, red-emitting phosphor, Li₂MgHfO₄:Mn⁴⁺, was developed for temperature sensing. An experimental analysis combined with density functional theory and crystal field calculations reveals that the sensitive temperature-dependent luminescence arises from nonradiative transitions induced by lattice vibration. Li₂MgHfO₄:Mn⁴⁺ also exhibits reliable recovery performance after 100 heating-cooling cycles due to the elimination of surface defects, which is rare but vital for practical application. This study puts forward a new design strategy for fluorescent thermometers and sheds light on the fundamental structure-property relationships that guide sensitive temperature-dependent luminescence. These considerations are crucial for developing next-generation fluorescence-based thermometers.