Extended Data Fig. 6: Mechano-optical response versus cycle # for single (15% Tm³⁺) piezochromic ANPs.

a. Mechano-optical response (percent change of the 800 nm / 700 nm -emission ratio versus applied force), for up to 9 compression cycles per particle, for 8 different piezochromic ANPs. b-d. Mechano-optical response (b), normalized initial (F = 0) brightness (c), and initial (F = 0) 800 nm / 700 nm -emission ratio (d) versus cycle #. Data are derived from 21 compression cycles on 8 piezochromic ANPs (excitation intensity: 1,131 ± 46 kW cm⁻²). Each compression cycle consists of 10–1000 emission versus force data points. Error bars depict the extrapolated errors derived from the 800 nm / 700 nm -emission ratio versus applied force fit values’ 95% confidence intervals, while compression cycles consisting of a lower number of emission-versus-force data points yield larger S.E.M.s. Data points in c are normalized to a 3 s integration time baseline (i.e., divided by their respective integration times, and multiplied by 3 s), so as to conform to data acquired for the other (pre-avalanching and avalanching) particles in this study – for comparison between particles (data in c was further normalized to a 1 s integration time baseline for NES derivation). Data in b, c, and d are colour-coded as in a (each colour represents a different single particle).