Intramolecular energy transfer in a two-photon absorbing naphtahlimide-triphenylamine dyad

When a triphenylamine (TPA) is incorporated to a fluorephore of 2-Ethyl-6-(1-piperidinyl)-1H-benz[de]isoquinoline-1,3(2H dione (EPQD), energy absorbed by EPQD unit will mostly transfer to TPA unit inside the new molecule 2-(4-Diphenylamino-phenyl)-6-(1-piperidinyl)-1H-benz[de]isoquinoline-1,3(2H)-dione (APQD) through electron transfer, and then relax with no fluorescence. APQD, whose fluorescence quenched by the intramolecular energy transfer, has a little larger two-photon absorption cross-section than its reference dye EPQD.