Synthesis of Silica Encapsulated Perylenetetracarboxylic Diimide Core–Shell Nanoellipsoids

Silica encapsulated perylenediimide (PDI) nanoellipsoids with core–shell structure have been synthesized in solution by a combination of precipitation method and sol–gel chemistry. Electron energy loss spectrum (EELS) analysis proves that the obtained composite particles consist of a PDI core and a silica shell. The UV–vis and fluorescence spectra show the strong π–π stacking state of PDI molecules in the composite colloids. The silica deposition process on the PDI surface can be well controlled allowing variation of the shell thickness from 10 to 50 nm. Thermogravimetrical analysis data indicate that the thermal stability of PDI increases after deposition of a silica shell. The photostability of PDI is enhanced by the introduction of silica shell. The silica coating improves the dispersibility of PDI in different solvents and in polymer films.