Fig. 2: Characterization of the lifetime properties of WINPs. | Light: Science & Applications

Fig. 2: Characterization of the lifetime properties of WINPs.

From: Water-insensitive NIR-I-to-NIR-I down-shifting nanoparticles enable stable biomarker detection at low power thresholds in opaque aqueous environments

Fig. 2

a Schematic of the microscopy setup for single-particle-level analysis. Imaging camera (using the flipping mirror) or spectrograph (without using the flipping mirror). S stage, L lens, DBS dichroic beamsplitter, OBJ objective lens, FM flipping mirror. Scale bar, 5 μm. b Single-level photoluminescence images of UCNPs under 980 nm excitation (power density of 0–103 W cm−2) in dry (top) and wet (bottom) conditions. c Single-level photoluminescence images of WINPs under 800 nm excitation (power density of 0–103 W cm−2) in dry (top) and wet (bottom) conditions. d Corresponding excitation-power-dependent photoluminescence emission intensity curves of WINPs and UCNPs. Slope s, indicates the slope in the log-log plot. e Photoluminescence (PL) lifetime decay profiles at 800 nm of UCNPs under 980 nm excitation, measured in cyclohexane and water, respectively. f PL lifetime decay profiles at 865 nm of WINPs under 800 nm excitation, measured in cyclohexane and water, respectively. (a.u. arbitrary units.)

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