Transmission spectra of all samples were acquired using a Cary 5000 UV-Vis-NIR spectrophotometer (Agilent Technologies) for wavelengths ranging from 300 nm to 3000 nm and a Nicolet iS50 FTIR spectrometer (ThermoFisher) for wavelengths longer than 3000 nm. Each sample was measured multiple times with a metal plate containing a ~4 mm hole in the light path between the sample and the detector to limit forward scattering from being quantified as transmission. The spectra shown in Figure and,S10 represent an average of three spectra acquired over three different ~20 mm 2 areas of each sample.