High efficient fluorescent stable colloidal sealed dye-doped mesostructured silica nanoparticles

The fluorescence properties of colloidal sealed Rhodamine 6G doped mesostructured silica nanoparticles prepared by a one-pot templated base-catalyzed sol-gel self-assembly method are reported. The hybrid organic-inorganic nanoparticles is tested against water and alcohols dye leaching showing larger resilience to leaching in water, high quantum yield despite the large dye concentration and huge relative brightness up to 1.5 × 105 emitting molecules per nanoparticle. This super fluorescence is 3 times larger of comparable systems and 100 times larger than the fluorescence of CdSe/ZnS quantum dots. The surfactant used for the formation of the mesostructure plays a key role both as dye splitting element and as sealing agent against leaching effect. The resilience to dye leaching in water is further justified by the formation of core-shell architectures made up of mesoporous core and homogeneous low-porous silica shell of 5-12 nm in thickness due to long aging condensation reaction of surface silanols in water. In addition, the comparison with a reference no-doped silica sample points out a possible alternative synthetic strategy to tune the structural, morphological and textural properties of silica-based nanosystems: properly engineering can exploit the effect of dye molecules addition on nanoparticles mean size, polydispersity and mean thickness of matrix silica walls.