Multimode emission from Bi3+ induced oxygen vacancy engineering in spinel-type phosphor for versatile optical applications

Long afterglow phosphors for optical information storage and anti-counterfeiting applications have attracted increasing attention due to their inherent atom defects triggered persistent emission properties. However, precisely modulating the defect concentration and trapping energy level distribution in phosphors is still a huge challenge, let alone understanding the relationship between the defect concentration/position and afterglow behavior. Herein, we reported the Bi 3+ induced oxygen vacancy engineering in MgGa 2 O 4 (MGO) phosphor for controlled afterglow and dynamic multimode emissions. A variety of spectrum characterizations and theoretical calculations confirmed that doping with a higher concentration of Bi 3+ leads to more oxygen defects in MGO host. Specifically, increasing oxygen defects can result in a gradually enhanced ratio of shallow trap and decreased ratio of deep trap in the band gap of MGO phosphor, being responsible for the modulated afterglow behaviors. Moreover, the abundant trapping state also induced dynamic luminescence performance upon persistent UV light irradiation. By virtue of the fantastic afterglow and dynamic luminescence emission properties, optical storage and information encryption applications of the prepared MGO:Bi 3+ phosphors were developed. The vacancy engineering for tunable multimode emission proposed in this work can spur several new ideas and concepts in designing advanced phosphors for multifunctional optoelectronic applications.