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Upconversion and optical nanothermometry in LaGdO3: Er3+ nanocrystals in the RT to 900 K range

Abstract: The search for material hosts being able to incorporate Er3+ impurities with a thermally stable structure and a high melting temperature is priority in optical thermometry. In this work, we report on the structural and spectroscopic characterization of Er3+-doped and Yb3+/Er3+-codoped LaGdO3 nanocrystals synthesized via the sol-gel Pechini method. X-ray diffraction and Raman spectroscopy unequivocally show that the synthesis method provides nanocrystals with a single-phase B-type monoclinic structure (space group, C2/m). Intensity decay curves, I(t), were measured to investigate the efficiency of upconversion processes yielding green emission. We showed that an energy transfer upconversion (ETU) process involving Yb-Er pairs governs visible emission upon near-infrared (NIR) excitation. The temperature dependence of the thermalized green luminescence at 525 nm (2H11/2 ? 4I15/2) and 549 nm (4S3/2 ? 4I15/2) was checked for thermometric applications in the room temperature (RT) to 900 K range. We demonstrate that the B-type monoclinic phase of LaGdO3 is stable from low temperatures up to 900 K. Doped with Er3+, it shows suitable thermometer capabilities with a maximum sensitivity of S = 4.3 × 10-3 K-1 at 554 K and a relative sensitivity decreasing from its maximum value at 0 K to SR = 1.2 × 10-2 K-1 at 298 K. The results suggest that LaGdO3 in its B-type monoclinic phase is a promising material as a wide-range temperature sensor, without any further surface protection.

 Autoría: Gutiérrez-Cano V., Rodríguez F., González J.A., Valiente R.,

 Fuente: Journal of Physical Chemistry C, 2019, 123, 29818-29828

 Editorial: American Chemical Society

 Fecha de publicación: 01/11/2019

 Nº de páginas: 11

 Tipo de publicación: Artículo de Revista

 DOI: 10.1021/acs.jpcc.9b06959

 ISSN: 1932-7447,1932-7455

 Proyecto español: MAT2015-69508-P

 Proyecto europeo: info:eu-repo/grantAgreement/EC/H2020/629161/EU/NanoCrystals in Fibre Lasers/NCLas/

 Url de la publicación: https://doi.org/10.1021/acs.jpcc.9b06959

Autoría

VANESA GUTIERREZ CANO

JESUS ANTONIO GONZALEZ GOMEZ