Tunable broadband photoluminescence from bismuth‐doped calcium aluminum germanate glasses prepared in oxidizing atmosphere

Tunable photoluminescence (PL) from transparent inorganic glass matrices is of interest for applications demanding a semitransparent photoconverter that does not elastically scatter incoming light. For this purpose, bismuth (Bi)‐doped optical materials exhibit unique spectral characteristics in terms of bandwidth and emission tunability. Here, we demonstrate a facile route for preparing such converters from Bi‐doped calcium‐aluminate and calcium‐aluminogermanate glasses. These glasses offer tunable PL across the near violet and visible‐to‐near‐infrared (NIR) spectral range, with an emission lifetime in the range of 300 μs. The addition of GeO 2 exerts a decrease in optical basicity, which in turn enables the stabilization of NIR‐active low‐valence Bi species for broadband NIR PL

Novel persistent and tribo-luminescence from bismuth ion pairs doped strontium gallate

International audienceUnlike the many transition metal ions- and rare earth ions-doped long persistent materials, at present, few bismuth ion-doped long persistent materials have been reported. In this work, we report on a novel phosphor Sr3Ga4O9:Bi3+ that combines photoluminescence, long persistent luminescence and triboluminescence at room temperature. The compound glows in the green (530 nm) and red (680 nm) spectral regions upon excitation in the range 240–400 nm. From calculation results based on the original theory of electronegativity, we obtain the energy level structure of Bi3+ (doped into Sr sites 1–3) in Sr3Ga4O9:Bi3+, from which it is inferred that these emissive features are ascribed to Bi3+ pairs. These emissions are also produced under mechanical action and show a persistence up to 6.5 hours after removal of ultraviolet super-bandgap irradiation. This is the first observation of such multi-functionality for an inorganic solid activated with Bi3+. Furthermore, considering our insights into the elusive nature of Bi3+ luminescence, we expect that the Bi3+-doped mechanoluminescence (ML) material will further promote the development of ML