01 November 2025 - Publication in Adv. Opt. Mat.

Precise positioning of quantum emitters is essential for next-generation photonic technologies, yet conventional free-space optical trapping methods require high laser powers that damage sensitive nanoparticles through heating. Here, ultralow-power trapping of biocompatible molecular graphene quantum dots (GQDs) is demonstrated using metamaterial plasmonic tweezers, achieving record-high normalized trap stiffness values at low intensities. Custom 19-nm molecular GQDs containing twisted double[7]carbohelicene (D7H) molecular cores are synthesized and their trapping dynamics are systematically investigated across dual hotspot types in the metamaterial array. The results establish safe operating regimes for heat-sensitive quantum emitters and reveal the fundamental interplay between optical and thermal forces in plasmonic trapping systems. This platform enables efficient nanopositioning of quantum emitters in ordered arrays while maintaining biocompatibility and photostability, opening pathways toward scalable single-photon source architectures and bioimaging applications.