From a J-to an H-Aggregation

To take advantage of hybrid materials (high resistance to thermal, chemical, and 

The study of the optical properties of thin films revealed that the hydrolysis-polycondensation process resulted in a modification of the supramolecular organization of Si(OEt)3-lmPV in the solid state. Si(OEt)3-lmPV was hydrolyzed and polycondensed using tetrabutylammonium fluoride (TBAE) as a catalyst. The films obtained by the sol-gel process using the TBAE are designated by Si (OEt)3-lmPV-E. 

Changes in absorption and emission spectra could be attributed to a change in the aggregation of the chromophores in relation to this confinement in the silica network (Si(OEt)3-ImPV-F) or not (Si(OEt)3-lmPV) (Eigure 4.17). 

The spectroscopic behavior observed for confined Si(OEt)3-ImPV-F (blue-shifted absorption, decreased intensity, and red-shifted emission) could be attributed to an H-type aggregation such an aggregation may reasonably be expected from a card pack orientation of the distyrylbenzene imide chromophores in the silicate network. The formation of the silyl network supports a face-to-face organization of chromophores. 

The issue remains the introduction of a significant proportion of chromophores in a silica network while avoiding aggregation responsible for loss of 

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