Preparation and Investigation of Quantum-Dot-Loaded Hollow Polymer Microspheres

In this work, hollow poly(methyl methacrylate) (PMMA) microspheres loaded with CdSe/CdS core–shell quantum dots (QDs) were fabricated onto hydrophilic glass substrates using a spray-drying method. The PMMA microspheres were investigated using scanning electron microscopy, confocal microscopy, and fluorescent lifetime imaging microscopy (FLIM) to investigate the morphology of the spheres and confirm their hollow structure. The QDs were used as fluorophores in confocal microscopy to observe the central cavity of the microspheres and in solid-state photoluminescence spectroscopy to observe whispering gallery modes (WGMs), demonstrating the high optical quality of the hollow microspheres and their potential application as optical microresonators.