One-pot synthesis of enhanced dye-sensitized persistent luminescence nanoparticles to alleviate concentration quenching†

Abstract

ZnGa₂O₄:Cr³⁺ (ZGC) persistent luminescence (PersL) nanoparticles (PLNPs) are extensively researched in the fields of bioimaging and therapy due to their simple preparation and uniform morphology. Typically, the luminescence intensity increases with the Cr³⁺ concentration of luminescent ions up to an optimal range of 0.4–0.6%, beyond which concentration quenching often occurs, leading to a decrease in both intensity and lifetime. In this study, we introduce a one-pot solvothermal synthesis method to address the issue of concentration quenching by coating ZGC_n PLNPs with an optimal concentration of the organic dye OAm–RhB, yielding ZGC_n@OAm–RhB PLNPs. Here, OAm–RhB serves as a strong absorber, harvesting energy and subsequent energy transfer to Cr³⁺. Notably, the Cr³⁺ doping concentration can be increased to 1.2% without causing concentration quenching. Strikingly, the energy transfer efficiency between OAm–RhB and Cr³⁺ is up to 71%. ZGC_1.2@OAm–RhB PLNPs significantly enhance the afterglow intensity by 60 times and extend the lifetime from 85.35 to 112.05 s. After modification with DSPE-PEG and HA, ZGC_1.2@OAm–RhB@PEG@HA PLNPs were obtained, demonstrating good cellular uptake and precise tumor imaging, guiding complete tumor resection confirmed by H&E staining analysis. This strategy is anticipated to mitigate the concentration quenching of other PLNPs for improving PersL performance.