Synthesis of the multifunctional Cubic-Gd2O3:Er3+,Yb3+ nanothermometers from the nanoscaled Metal–Organic framework of Gd-BTC:Er3+,Yb3

• Published in: Optical materials 2024-03, Vol.149, p.115149, Article 115149
• Main Authors: Giang, Lam Thi Kieu, Piotrowski, Wojciech M., Opalińska, Agnieszka, Le, Ngo Thi Hong, Yen, Nguyen Hai, Linh, Pham Hoai, Marciniak, Lukasz
• Format: Article
• Language: English
• Subjects: Cubic-Gd2O3:Er3+,Yb3+ nanothermometers; Gd-BTC:Er3+,Yb3+ NMOF; Metal–organic frameworks; Up-conversion
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2024.115149

In this paper, we present a green synthesis method that allows the obtained cubic-Gd2O3:Er3+,Yb3+ nanothermometers without using precursors derived from inorganic acids unlike other traditional methods. The performed TEM/HRTEM images, SAED patterns, and XRD analyses confirm the formation of cubic phase Gd2O3: Er3+,Yb3+ with average particle size about of 15 ± 1 nm after annealing the nanoscale metal-organic frameworks of gadolinium co-doped with 2% mol Er3+ and 20% mol Yb3+ ions (Gd-BTC:Er3+,Yb3+ NMOF) at 700 °C for 1 h. The process of formation of the Gd-BTC:Er3+,Yb3+ NMOF was also investigated in detail by SEM, XRD, EDS, BET, FT-IR and STA/TGA-DSC techniques. The up-conversion emission of the obtained cubic-Gd2O3:Er3+,Yb3+ nanothermometers were investigated in the 83–773 K temperature range upon 980 nm excitation. As it was proved the red to green emission intensities ratio of Er3+ ions changes monotonically in the whole analyzed temperature range. The calculated relative sensitivity of the luminescence thermometer based on the 2H11/2/4S3/2 → 4I15/2 to the 4F9/2 → 4I15/2 of the obtained cubic-Gd2O3:Er3+,Yb3+ nanothermometers reached 0.75%/K at 500 K. Additionally the faster thermal quenching of the 4F9/2 → 4I15/2 emission band in respect to the 4F9/2 → 4I15/2 of Er3+ results in the thermally induced change of the emission colour from red through yellow to green. Thus the chromatic relative sensitivities reached SRx = 0.2%/K and SRy = 0.225%/K at 710 K. Furthermore, the magnetic measurements also proved the soft magnetic property of Gd2O3:Er3+,Yb3+ with saturation magnetization (Js) reached of 8 emu/g at temperature of 150 K Obtained results confirms the application prospects of the multifunctional cubic-Gd2O3:Er3+,Yb3+ nanothermometers in the biomedical fields. •A green synthesis method that allows the obtained cubic-Gd2O3:Er3+,Yb3+ is presented.•A visual luminescent thermometer was presented-change in the chromatic coordinates.•Multimodal luminescent thermometer based on Gd2O3:Er3+,Yb3+ is demonstrated.