Synthesis and optical characteristics of organic light-emitting dot based on well-defined octa-functionalized silsesquioxane

This article reports the synthesis and characterization of a quantum-confined luminescent dot with size 2-3 nm using well-defined m-octa(bromophenyl) silsesquioxane (m-OBPS) as core. The highly regioselective bromination of octaphenylsilsesquioxane (OPS), which is an electron-deficient nanometer-sized molecule, has been synthesized using combined catalyst of iodine and zinc chloride at room temperature in dichloromethane solvent. Based on m-OBPS, a hybrid luminescent dot with well-defined structure was synthesized. UV absorption and PL spectra of this light-emitting dot remain same in dilute solution, condensed state, and solid solution. Furthermore, time-resolved PL study indicates that the exciton decay time of the light-emitting dot remains similar regardless in dilute solution, condensed state, or blended with other polymers, suggesting that the charge carriers are well confined within the individual light-emitting dot due to the unique star-like structure and shielding alkyl chain layer. The light-emitting nano-particles can be considered as isolated chromophores as both inter- and intra- molecular aggregation are prohibited.