Tunable broadband near-infrared emission from environmentally friendly Fe 3+-activated lead-free perovskites for spectral analysis and rapid nighttime recognition

With the increasing role of near -infrared (NIR) light sources in many fields such as food and industry, NIR emitting phosphors have flourished in recent years. In addition to the widely reported Cr 3 + -activated NIR phosphors, environmentally friendly Fe 3 + can also produce tunable broadband NIR spectra, which are expected to enrich the next generation of intelligent NIR light sources. In this work, a series of Fe 3 + -activated perovskitetype Sr 2 ScSbO 6 (SSSO) NIR phosphors were successfully prepared and an emission wavelength of 900 nm with a full width at half maximum (FWHM) of 110 nm was obtained. Through the crystal field engineering strategy, the lattice site of Sr 2 + was completely replaced by Ba 2 + and Ca 2 + to obtain Ba 2 ScSbO 6 (BSSO) and Ca 2 ScSbO 6 (CSSO), and the emission peak was continuously adjusted from 840 nm to 950 nm. When the temperature increased from 300 K to 400 K, BSSO:Fe 3 + , SSSO:Fe 3 + and CSSO:Fe 3 + could maintain 69 %, 82 % and 67 % of the original luminescence intensity, respectively. The opposite crystal field dependence between Fe 3 + and Cr 3 + was shown in double -layer perovskite-type antimonate materials, which could guide us to develop Fe 3 + -activated long -wavelength emission NIR phosphors. Benefiting from the long -wavelength emission of BSSO:Fe 3 + , SSSO: Fe 3 + , and CSSO:Fe 3 + , their application potential in the field of spectral analysis and rapid nighttime recognition were successfully demonstrated.