Highly-efficient cyan-emitting phosphor enabling high-color-quality lighting and transparent anticounterfeiting

Abstract

Constructing the broad-band emitting luminescent materials with high quantum yield is of great significance towards their widespread applications. Herein, series of Eu2+ activated, whitlockite-type Ca8ZnY(PO4)7 phosphors are developed towards bifunctional platform involving the white LED and anti-counterfeiting field. Benefiting from the typical 5d-4f transitions among Eu2+ ions, the broad asymmetric cyan-emission spectra (FWHM = 78 nm) is generated under 365 nm excitation with a highest quantum yield of ∼72.11 %. The optimal doping concentration of Eu2+ ions in the Ca8ZnY(PO4)7 host is determined as 4 % and the concentration quenching mechanism is mainly attributed to a dipole–dipole interaction. Impressively, after exploiting the newly discovered cyan-emitting phosphors Ca8ZnY(PO4)7:Eu2+, the CRI value of as-prepared warm w-LED devices is remarkably enhanced from 83.9 to 90.5. Moreover, the w-LED exhibits an applicable correlated color temperature (CCT = 4176 K) and good color stability. Additionally, the transparent anticounterfeiting film is fabricated based on the highly efficient phosphors and soluble PVA, which presents anticounterfeiting performances due to their bright cyan emission upon UV light. Notably, their sustainability, excellent flexibility and foldability provide more possibilities applied for anticounterfeiting field. These results suggest the highly efficient phosphors Ca8ZnY(PO4)7:Eu2+ are promising bifunctional luminescent platforms, for both high-color-quality lighting and anticounterfeiting applications.