Cationic substitution induces multicolor emission in YBaZn3-yMgyGaO7:Bi3+ phosphors for WLEDs and information encryption

Abstract

Currently, the development of innovative, efficient phosphors featuring near-ultraviolet excitation and broadband emission, notably Bi³⁺-activated phosphor, is pivotal for realizing high-performance white light-emitting diodes (WLEDs). In this work, we report a series of broadband orange-green emitting YBaZn_3-yMg_yGaO₇: Bi³⁺ phosphors with strong n-UV excitation. By employing cationic substitution, we successfully tuned the emission wavelength from 605 to 550 nm, thereby unlocking potential for multifunctional applications in solid state lighting and information encryption. YBaZn₃GaO₇:0.015Bi³⁺ phosphor generates 605 nm orange emission with a full width at half-maximum (FWHM) of 220 nm under 330 nm n-UV excitation, with high luminescence intensity and excellent thermal stability. In addition, the luminescence mechanism of Bi³⁺ ions in YBaZn_3-yMg_yGaO₇: Bi³⁺ was investigated thoroughly. A high-performance W-LED device has been fabricated, utilizing a unique YBaZn₃GaO₇:0.015Bi³⁺ phosphor and commercial blue and green phosphors, pumped by a 365 nm chip. This phosphor-converted (pc) WLED has an excellent color-rendering index (R_a) of 95.6 and a comfortable correlated color temperature (CCT) of 5193 K. This result indicates its potential applications in the field of health lighting. Furthermore, the orange-green YBaZn_3-yMg_yGaO₇: Bi³⁺ phosphor demonstrates precise information identification in information encryption, confirming its potential in this field.