Engineering Efficacy and Accuracy in the Optical Printing of Dielectric Nanocrystals.

Accurate single nanocrystal positioning tools are critical for emerging quantum and photonic technologies. Optical printing provides a platform to realize this positioning, but we need to understand the roles that solvent and surface functionalization play in controlling positional error, particularly for dielectric nanocrystals. Here, we characterize the impact of solvent and surface functionalization on nonresonant optical printing accuracy and efficacy, demonstrating accuracies of 50 nm. Changing solvent, nanocrystal concentration, and surface functionalization influences the number of attempts required to print nanocrystals, which we find is connected to positional error. Adding electrolytes to modify the interfacial DLVO potential reveals a unique regime where high irradiances minimize positional error while maximizing efficacy. Multiphysics simulations suggest that this regime results from photothermal effects and gradient forces. We validate these simulations by showing lower positional errors from substrates with higher absorption coefficients. These results will guide optical printing procedures for single nanocrystal positioning applications.