measured with a Shimadzu SALD-7500nano particle size analyzer. The powder was dispersed in isopropyl alcohol at a concentration of 1 mg/mL, sonicated, and measured in a quartz cell (Batch Cell SALD-BC75) with a 405 nm laser. The refractive index was set to 2.4 for these measurements based on literature for Nb2O5 at this wavelength. Scanning electron microscopy was performed with an FEI Apreo SEM operating with a beam current of 0.40 nA and a voltage of 10 kV.