(375f) The Effect of Solvent Selection on the Optical Trapping, Manipulation, and Patterning of Nanomaterials

The optical trap’s ability to manipulate nanoparticles in three dimensions using the radiation pressure of light and to measure piconewton forces, has enabled the investigation of a wide range of effects, including the laser-cooling of solids, the Casimir effect, and protein folding. In addition, the contactless control of a particle’s location makes the optical trap a premier technique to select individual particles from a dispersion and to pattern nanoparticles. However, there are no reports of optical trapping in non-aqueous liquid media, which limits the available library of nanoparticles for patterning.

Here, we demonstrate the optical trapping and patterning of nanowires and microspheres in a range of non-aqueous solvents for the first time. To characterize the trapping conditions, we employ the temperature-dependent photoluminescence of ratiometric Mn²⁺:ZnCdSe nanocrystals to measure the local temperature of trapped nanowires, observing temperatures >100°C above ambient conditions. We find that the choice of solvent influences the trap’s local properties, which drastically affects the optical trapping and patterning efficiency. Finally, we discuss the initial optimization of these parameters and model the heat transport, including convection, around the trapped particle.