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. 2020 Feb 18;11(3):1401–1416. doi: 10.1364/BOE.381480

Fig. 3.

Fig. 3.

Properties of UCNP films and evaluations of NIR illumination. (a) Schematic diagrams of the procedure of 980-nm laser illumination via UCNP films. (b) TEM or FESEM images of 20 mg/ml UCNP and 200 mg/ml UCMP on the film (top left: TEM image of 20 mg/ml UCNP; top right: FESEM image of PDMS film; bottom left: FESEM image of 20 mg/ml UCNP on a PDMS film; bottom right: FESEM image of 200 mg/ml UCMP on a PDMS film).(c) Schematic ideogram of emission spectrum detection of the UCNP films. (d-f) Emission spectrum of the UCNP films at different concentrations under 980-nm power at 1 W (d) and 5 W (e), and upconversion intensity with elevated UCNPs concentrations (f). (g) Pulses NIR laser successfully captured right ventricle via 10 and 20-mg/ml UCNP films (red line: 980 nm, 20 ms, 8 Hz, 1.5 W; black line: ECG). (h) NIR power threshold via 10 and 20 mg/ml UCNP films respectively. n = 5; The data are presented as the mean ± SEM. NS, P > 0.05, unpaired t-test. (i) ECGs of failed NIR pacing via 2.5- and 5-mg/ml UCNP films.