Fig. 5. (A) Schematic representation of spectroscopic ellipsometry (SE) measurement of the thickness of a thin film of c-H3 in the PMMA matrix on Si wafer. (B) Thickness changes of a thin film of c-H3 in the PMMA matrix upon blue light irradiation (blue LED, 5.10 mW cm⁻²) and heating (80 °C); MSE = mean squared error of the fitting model applied to fit the data. See ESI† for details. (C) δѰ and (D) δΔ spectroscopic ellipsometry spectral difference of the film before and after the blue light irradiation, where δѰ/Δ = Ѱ/Δ before irradiation, – Ѱ/Δ after irradiation, and Ѱ and Δ are the ellipsometric parameters. (E) Emission spectral changes of a thin film of c-H3 (in PMMA) on Si wafer upon blue light (5.10 mW cm⁻²) irradiation (for 2 min).