Nanocrystalline (HoxY1−x)2Ti2O7 luminophores for short- and mid-infrared lasers

• Published in: Journal of sol-gel science and technology 2023-08, Vol.107 (2), p.320-328
• Main Authors: Mrázek, Jan, Kamrádková, Soňa, Buršík, Jiří, Skála, Roman, Bartoň, Ivo, Vařák, Petr, Baravets, Yauhen, Podrazký, Ondřej
• Format: Article
• Language: English
• Subjects: Ceramics; Chemical composition; Chemistry and Materials Science; Composites; Crystal lattices; Energy; Fluorides; Glass; Holmium; Infrared lasers; Inorganic Chemistry; Lasers; Luminescence; Materials Science; Nanocrystals; Nanotechnology; Natural Materials; Optical and Electronic Materials; Optical properties; Original Paper: Sol–gel and hybrid materials for optical; Phonons; photonic and optoelectronic applications; Pyrochlores; Radiative lifetime; Science; Sol-gel processes; Spectrum analysis; Unit cell
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-023-06113-x

We present a versatile sol–gel approach for low-phonon nanocrystalline (Ho x Y 1−x ) 2 Ti 2 O 7 , x  =  exhibiting luminescence within the spectral range 2000–3000 nm. The nanocrystalline structure of (Ho x Y 1−x ) 2 Ti 2 O 7 was studied and the effect of the composition and phonon energy on the luminescence properties was evaluated. Regular distribution of Ho 3+ ions inside the pyrochlore crystal lattice was proved leading to a regular increase of the unit cell parameter. The luminescence intensity recorded at 2025 nm reached a maximum for the composition (Ho 0.03 Y 0.96 ) 2 Ti 2 O 7 . The radiative lifetime recorded at 2025 nm regularly decreased with increasing content of Ho 3+ ions inside the pyrochlore lattice from 6.32 to 0.22 ms. The phonon energy of the samples was smaller than 700 cm −1 allowing the luminescence spectral range to be extended up to 2900 nm. Further tailoring of the chemical composition can improve the emission at 2860 nm providing a promising high thermally and chemically stable alternative to conventional fluoride or chalcogenide glasses. Graphical Abstract Highlights We present a versatile sol–gel approach to preparing (Ho x Y 1−x ) 2 Ti 2 O 7 x  = . The content of Ho 3+ ions in the lattice has a major impact on the luminescence properties. The optimal content of Ho 3+ ions to maximize the luminescence intensity is identified. Low phonon energy of (Ho x Y 1−x ) 2 Ti 2 O 7 allows the radiative transition at 2860 nm to be activated.