Synthesis and applications of multi-mode color tunable phosphors BaZrSi3O9:Bi3+,Eu2+ for w-LEDs and anti-counterfeiting

The development of efficient, tunable excitation/emission and sustainable luminescence mode single-phase inorganic luminescent materials plays an important role in the progress of information encryption and advanced anti-counterfeiting technology. Herein, a general high temperature solid phase method was employed to synthesize Bi 3+ and Eu 2+ co-doped BaZrSi 3 O 9 (BZSO) phosphors, which show properties of spectral tuning and temperature sensitivity and have potential applications in lighting and anti-counterfeiting. The optimized cyan-emitting phosphor BZSO:0.03Bi 3+ ,0.05Eu 2+ phosphor in w-LED devices to significantly improves the color rendering index (CRI) from 89 to 93, while the correlated color temperature (CCT) is reduced from 5002   K to 4609   K. By substitution of Bi 3+ with varying concentrations of Eu 2+ in BZSO, the luminescent color of the hosts can be tuned from yellow to green. The photoluminescence (PL) spectra of BZSO:0.03Bi 3+ ,0.05Eu 2+ sample varies with the excitation wavelength (270 to 420   nm). The prepared powder was mixed with soluble polyvinyl alcohol (PVA) to prepare advanced anti-counterfeiting ink. The prepared of BZSO:0.03Bi 3+ ,0.05Eu 2+ /PVA composite luminescent film not only has good thermal stability, water resistance, transparency, flexibility, foldability and easy processing performance, but also has the characteristics of adjustable multi-mode luminescence and sustainable luminescence. In short, this changing-color and long-lasting luminescent fluorescent material offers the possibility of sophisticated advanced anti-counterfeiting applications in the future.