Dynamics of the energy transfer involved in a diarylethene-perylenebisimide dyad: comparison between the molecule and the nanoparticle level

Photochromic materials are widely used to achieve fluorescence photoswitching. Understanding the energy transfer processes occurring in these systems would be an advantage for their use and better optimization of their properties. In this scope, we studied a diarylethene-perylenebisimide (DAE-PBI) dyad that presents a bright red emission and a large ON-OFF contrast, both in solution and in an aqueous suspension of nanoparticles (NPs). Using ultrafast transient absorption spectroscopy, the excited state dynamics was characterized for this dyad in THF solution and compared to its behavior in NPs state. An efficient energy transfer process between the PBI fluorophore and the DAE photochromic unit in its closed form was demonstrated, occurring in a few hundreds of femtoseconds. [Graphics]

Automated summary

A diarylethene-perylenebisimide (DAE-PBI) dyad with bright red emission and large ON-OFF contrast was studied, and its excited state dynamics were characterized in solution and nanoparticle suspension. Efficient energy transfer between the fluorophore and photochromic unit was demonstrated, occurring in a few hundreds of femtoseconds.