Figure 2.
Mechanosensitivity of
LS nanoparticles. (a) Upconversion spectra
of LS nanoparticles loaded in a DAC with methanol:ethanol (4:1) pressure
medium at 0.2 GPa loading (solid black), 5.2 GPa maximum (solid maroon),
and final release pressure after three cycles (dashed black). Each
spectrum is normalized to its own green emission peak to visualize
the relative enhancement of red emission upon compression. (b) For
three pressure cycles, we record the percent change in the ratio from
the fitted ambient value (
). An error-weighted
linear fit of all the
data points provides a slope or the mechanosensitivity value. LS nanoparticles
are over 3× more sensitive than AS nanoparticles with oleic acid.
Data for AS UCNPs were previously reported.38 The error on mechanosensitivity is the 95% confidence interval of
the fit. Error bars on markers indicate the standard deviation from
three spectra collected at each pressure point and may lie within
the marker.