Nanolab 660 dualbeam

Colloidal crystal films were coated with Pt/Pd (∼5 nm) to minimize charging effects, prior to imaging with a Helios Nanolab 660 Dual Beam (FEI) at an acceleration voltage of 2 kV and a working distance of ∼4 mm. The images used for quantitative crystallographic analysis were acquired in immersion mode with secondary electron mode with a beam current of 0.05 nA to 0.1 nA and a dwell time of 10 μs to 30 μs. The imaging conditions were maintained constant for each dataset to ensure consistency in image quality. The magnification was calibrated with a standard SEM calibration sample. The SEM images of the colloidal particles were imported into Fiji (64 (link)) and subsequently converted into eight-bit images for further processing. Preprocessing included background flattening and a Gaussian blur step to smooth the intensity distribution within individual particles. The images were next binarized, and a further watershed treatment was performed to separate any connected particles. Individual particles were then identified and registered, from which the particle area, radius, and circularity were determined for statistical analysis. The bin widths in the histogram plots were determined following the method proposed by Scott (65 ), where the optimal bin width h_n is given by 3.49sn^−1/3. Here s is the SD, and n is the sample size.