Non-metallic plasmon-assisted upconversion fluorescence for ultrasensitive hydrogen peroxide detection from nM to μM.

Precise monitoring and quantification of H 2 O 2 is highly urgent and of great significance for biomedicine, food safety, environmental monitoring, etc . Herein, we proposed a facile near-infrared (NIR) excited fluorescent probe composed of upconversion nanoparticles (UCNPs) and non-metallic plasmonic WO 3- x for ultrasensitive quantitative H 2 O 2 detection. Plasmonic WO 3- x with oxygen vacancy-induced LSPR achieved over 680-fold enhancement of upconversion fluorescence at 520 nm, and also acts as the sensitive recognition site for H 2 O 2 . H 2 O 2 quenched the LSPR band of plasmonic WO 3- x , further significantly influencing adjacent fluorescence signals depending on its concentration. The probe exhibits a good linear response to H 2 O 2 with a low detection limit (10 -9 M) and a wide concentration range (0-50 μM), and shows satisfactory application in the determination of H 2 O 2 in blood and milk. This work may provide new ideas for the development of non-invasive fluorescent nanoprobes and plasmon-assisted biochemical detection methods.