Large temperature tuning of the emission color of a phosphor by dual use of Raman and photoluminescence signals

• Published in: Materials horizons Vol. 7; no. 4; pp. 111 - 115
• Main Authors: De, Arnab, Ranjan, Rajeev
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 01.01.2020
• Subjects: Barium titanates; Color; Electric fields; Emission; Erbium; External pressure; Ferroelectric materials; Ferroelectricity; Low temperature; Phosphors; Photoluminescence; Signal processing; Temperature effects; Tuning
• ISSN: 2051-6347; 2051-6355
• DOI: 10.1039/c9mh01796h

The ability to tune the emission color of materials by external stimuli like electric field, pressure, temperature, etc. , offers avenues to design light-based sensors and devices. We report here a new strategy which enables large temperature tuning of the emission color of a lanthanide phosphor by combining Raman and photoluminescence (PL) signals. The phenomenon and the associated mechanism, demonstrated on Eu, Er doped BaTiO 3 , shows the emission color to change from orange to green when cooled down to 10 K. The large color tuning is a consequence of synergy of the two processes: (i) significant enhancement of the Raman signal due to gradual structural ordering in the rhombohedral ferroelectric phase of the host BaTiO 3 and (ii) anomalous low temperature quenching of the PL emission of the doped Eu 3+ by trap states. We show that this contrasting temperature effect on the PL and the Raman signals can be used as a powerful strategy to design phosphor materials for high performance optical thermometry. High performance optical thermomertry by combining Raman and photoluminescence signals from phosphor materials.