Persistent luminescence nanoparticles (PLNPs) are an emerging type of optical nanomaterial that possess long-lasting afterglow after the excitation has stopped. Recently, bottom-up synthesis of PLNPs has offered uniform and small nanocrystals that are desirable for various bioapplications. However, the lack of a simple method to enhance the afterglow of these PLNPs is one of the key obstacles hindering their further development and applications. Herein, a simple strategy is demonstrated that can amplify both light and X-ray charged persistent luminescence in monodispersed Zn 2 GeO 4 :Mn PLNPs via the non-equivalency substitution of zinc ions with lithium ions in the lattice matrix and concomitant to the electron traps tailoring. It is significant that, in addition to increasing the intensity of the afterglow, this nanoscale atomic level substitution can preserve the desirable uniform size and morphology of the PLNPs. Furthermore, since the two excitations (light and X-ray) are independent of each other, a light/X-ray orthogonally encrypted spatio-temporal dual-dimensional afterglow anti-counterfeiting is demonstrated via these nanoparticles. It is believed that this simple method offers a foundation for new opportunities to unleash the optical performance in PLNPs. This will also pave the way to the development of such PLNPs for numerous photonic and bioapplications, which are limited in existing methods.

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Near‐infrared (NIR) persistent luminescent nanoparticles (N‐PLNPs) endow a long‐term in vivo imaging with deep tissue penetration and high signal to noise ratio. However, synthesis route and applicable afterglow center for N‐PLNPs are still limited. Here, we report on a new synthesis by employing chemical precipitation as the central pivot, which is simpler and has controllable and reproducible routes than the existing technique. We also introduce Fe3+ ion as a new member to join the group of afterglow emitters. Although its NIR luminescence is ubiquitous, its NIR afterglow is still almost never reported. In this paper, SrAl12O19: Fe3+ N‐PLNPs display a NIR persistent luminescence from 750 to 1000 nm, which is assigned to 4T1(4G)→6A1(6S) transition of Fe3+. Furthermore, a surface‐amination technique is proposed to improve the stability of SrAl12O19: Fe3+ N‐PLNPs in aqueous solution. After encapsulating the N‐PLNPs with 3‐aminopropyl triethoxysilane (APTES), SrAl12O19: Fe3+ @APTES nanocomposites exhibit a hydrophilic stability beyond 20 days in aqueous solution. The results make them valuable in studying the biological functions of biomolecules and monitoring cellular networks in their native contexts.

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