Broadband near-infrared emission in double perovskite phosphor BaLaMgTaO6:Cr3+ for organic compound detection, night vision and biological imaging

Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) can enable material identification by leveraging the absorption differences of specific functional groups (e.g., C-H and O-H) in the NIR region. The basic requirement for organics detection of NIR pc-LEDs is broadband emission that covers the strong absorption range of the functional groups. This work reports a new double perovskite matrix Cr 3+ -doped BaLaMgTaO 6 (BLMTO:Cr 3+ ) with 800 nm - 1200 nm broadband NIR emission upon 467 nm excitation, effectively covering the absorption regions of C-H and O-H bonds. Utilizing the first-principles calculations, crystal field theory and a variety of characterization methods, the spectral properties, the site occupancy of Cr 3+ and the temperature and concentration dependent spectra are fully demonstrated. Notably, by introducing Li + as a charge compensator, the spectra emission intensity increased to 1.67 times and the QY enhanced to 1.36 times. It is speculated that the intervention of Li  +  may make the charge balance after 2Cr 3+ → Mg 2+  + Ta 5+ substitution and form a more stable lattice environment. Finally, the NIR pc-LEDs assembled with BLMTO:Cr 3+ , Li + enables multi-applications in organic solution detection, biological imaging and night vision, paving the way for the development and application of multifunctional NIR pc-LEDs.