Near-infrared luminescence and high thermal stability of Rb2NaScF6:Cr3+ phosphor for spectroscopy applications

The search for chromium-doped near-infrared phosphor for spectroscopy application has attracted widespread concern. Herein, we prepared a double-perovskite fluoride phosphor, Rb2NaScF6:Cr3+ (abbreviated as RNSF:Cr), with wide blue excitation and near-infrared emission bands using a co-precipitation method. The crystal and electronic structures, as well as the luminescent properties were systematically investigated. Evidences show that RNSF offers a weak coordination environment and a wide bandgap for Cr3+ doping. By virtue of the weak electron–phonon coupling effect and the large activation energy, a high photoluminescence thermal stability was observed at 150 °C, with a ratio of 92% of that at 25 °C. In view of the high thermal stability, RNSF:Cr phosphor was incorporated into phosphor-converted light-emitting diodes to evaluate its potential use for near-infrared spectroscopy applications.