Single-particle measurements of chiral nanostructures have the potential to offer more detailed insights compared to the ensemble-averaged signals obtained in ensemble circular dichroism spectroscopy. For instance, single-particle circular differential scattering (CDS) studies have revealed the effects of structural heterogeneity in chiral plasmonic nanostructures. However, differential light-matter interactions of 3D chiral nanostructures caused by diverse orientations on the supporting substrate remain largely unexplored. Here, the CDS of DNA origami-templated twisted gold nanorod (AuNR) dimers on a glass support is investigated. With the help of correlated scanning electron microscopy and electromagnetic simulations, it is demonstrated how the broad diversity of spectral lineshapes and signal intensities as well as sign of the CDS originates mainly from four different orientations of the chiral dimer once deposited from solution on the substrate and dried. Most surprisingly, it is found that even for the same enantiomer a sign reversal is possible depending solely on the dimer orientation when deposited on the support. These results are important for the correct interpretation of single-particle chiroptical studies and furthermore provide valuable insights into the design of substrate-supported chiral plasmonic metamaterials.
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