We have used optical tweezers with shaped apertures in metal films to hold onto individual nanoparticles including erbium containing nanoparticles and perovskite quantum dots. In this talk, I will talk about our ability to isolate nanocrystals with just one erbium emitter, paving the way for single photon sources at low loss fiber wavelengths. I will also talk about our new work on in-situ characterization and assembly of perovskite quantum dots, allowing to relate size to emission wavelength and look at quantum hybridization.