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Title: Scintillating and Photoluminescent Ratiometric and Visual Luminescence Thermometry Based on the Ce3+-Doped Eutectic Structures

Authors: K. Bartosiewicz, M. Szymczak, M. Yoshino, T. Horiai, R. Tomala, J. Zeler, A. Owczarek, D. Szymanski, M. E. Witkowski, V. Jarý, W. Drozdowski, E. Zych, A. Yoshikawa, L. Marciniak

Journal: ACS Applied Materials & Interfaces

DOI: 10.1021/acsami.5c16426   

The study conducted in a collaboration between Institute of Physics, Czech Academy of Sciences (Czech Republic), New Industry Creation Hatchery Center (Japan), National Institute of Advanced Industrial Science and Technology (Japan), University of Wrocław (Poland), Nicolaus Copernicus University in Toruń (Poland) and Institute of Low Temperature and Structure Research PAS (M. Szymczak, R. Tomala, D. Szymanski and L. Marciniak) presents a new class of Ce³⁺-doped YAG-YAP eutectic crystals with integrated photoconversion and thermal sensing functionalities. These materials are fabricated via directional solidification at controlled rates (0.1-0.9 mm/min), allowing precise tuning of their microstructure and dopant distribution.

The eutectics form a lamellar composite of YAG (garnet) and YAP (perovskite) phases. Ce³⁺ ions preferentially incorporate into the YAG domains, particularly at higher growth rates. The solidification rate directly influences the domain size and optical properties: slower rates produce larger domains and higher blue light transmission through YAP, while faster rates increase scattering and absorption. This enables control over correlated color temperature (CCT) in the emitted light.

In addition to photoconversion, the material supports dual-mode temperature sensing via ratiometric luminescence thermometry, operating under both photoluminescence (PL) and X-ray-induced scintillation. The thermal sensitivity varies with excitation mode, reaching up to 1.1% K^-1 under scintillation. The scintillation-based sensing also allows passive temperature monitoring without external light sources, activated by ionizing radiation.

This integration of morphology-dependent optical tuning and modality-specific thermal sensing makes the eutectic crystals suitable for use in high-temperature or radiation-rich environments.

The details of these studies have been published in ACS Applied Materials & Interfaces.