NIR-I/III afterglow induced by energy transfers between Er and Cr codoped in ZGGO nanoparticles for potential bioimaging

Herein, Cr3+ and Er3+ codoped zinc gallogermanate (ZGGO) nanoparticles with average size of similar to 60 nm was synthesized via a hydrothermal path. It was found that near infrared (NIR)-III (similar to 1540 nm) afterglow was realized in ZGGO:Cr3+,Er3+ nanoparticles based on the successive energy transfer (ET) from Cr3+ to Er3+ after the stoppage of low-dose (60 mSv) X-ray irradiation. Meanwhile, the upconverted afterglow at 696 nm was produced via the ET from Er3+ to Cr3+ under different NIR light (808, 980, and 1532 nm) irradiations. Our results demonstrated that an X-ray pre-irradiation and a subsequent 980-nm light re-excitation might be a good strategy for realizing potential bioimaging. In particular, local-tissue NIR-I afterglow imaging using Cr3+ and Er3+ codoped ZGGO nanoparticles can be easily acquired by one-step 980-nm laser radiation. Furthermore, NIR-I/III afterglow mechanisms of ZGGO:Cr3+,Er3+ nanoparticles after stopping X-ray or different NIR lights (808, 980, and 1532 nm) irradiations were given.

Automated summary

The research found that ZGGO:Cr3+,Er3+ nanoparticles can achieve NIR-III afterglow and upconverted afterglow. Potential bioimaging can be realized through X-ray pre-irradiation and subsequent 980 nm light re-excitation.