RGB-tricolor multimodal luminescence of Ce3+ and Mn2+ in Mg2Al4Si5O18 via site occupancy engineering for anticounterfeiting applications

Abstract

Multimodal luminescent materials have shown important applications in anti-counterfeiting and information encryption, however, mostly difficult to adjust optical properties with the structure, which leads to relatively constant emission position and less selectable excitation wavelength. Herein, Ce and Mn co-doped MgAlSiO phosphors are designed for the applications in RGB-tricolor multimodal anti-counterfeiting. Due to site occupancies, energy transfer and different thermal behaviors of Ce and Mn emissions, the emitting color of MgAlSiO: Ce, Mn is rich and tunable with different excitation wavelengths, doping concentrations and temperatures. The site occupancies of Ce and Mn are clarified with crystal field analysis and in-depth into transitions energies of Ce and Mn. The energy transfer mechanism between Ce and Mn is analyzed via Inokuti-Hirayama model. The difference of thermal stabilities of Ce and Mn emissions is interpreted with construction of vacuum referred binding energy scheme. The as-designed molds of information encryption and decryption with MgAlSiO: Ce, Mn phosphors demonstrate the potential applications in anti-counterfeiting. The work provides an effective way for exploring Ce and Mn doped phosphors with RBG-tricolor multimodal luminescence.