A General Ammonium Salt Assisted Synthesis Strategy for Cr3+-Doped Hexafluorides with Highly Efficient Near Infrared Emissions

摘要

The discovery of highly efficient broadband near infrared (NIR) emission material is urgent and crucial for constructing NIR lighting sources and emerging applications. Herein, a series of NIR emission hexafluorides A(2)BMF(6):Cr3+ (A = Na, K, Rb, Cs; B = Li, Na, K, Cs; M = Al, Ga, Sc, In) peaking at approximate to 733-801 nm with a full width at half maximum (FWHM) of approximate to 98-115 nm are synthesized by a general ammonium salt assisted synthesis strategy. Benefiting from the pre-ammoniation of the trivalent metal sources, the Cr3+ can be more efficiently doped into the A(2)BMF(6) and simultaneously prevent the generation of the competitive phase. Particularly, Na3ScF6:Cr3+ (lambda(em) = 774 nm, FWHM approximate to 108 nm) with optimal Cr3+-doping concentration of 35.96% shows a high internal quantum efficiency of 91.5% and an external quantum efficiency of approximate to 40.82%. A lighting emitting diode (LED) device with a NIR output power of approximate to 291.05 mW at 100 mA driven current and high photoelectric conversion efficiency of 20.94% is fabricated. The general synthesis strategy opens up new avenues for the exploration of Cr3+-doped high efficiency phosphors, and the as-obtained record NIR output power demonstrates for NIR LED lighting sources applications.

关键词