Two-photon absorption and piezofluorochromism of aggregation-enhanced emission 2,6-bis(p-dibutylaminostyryl)-9,10-bis(4-pyridylvinyl-2)anthracene

Abstract

Cruciform 2,6-bis(p-dibutylaminostyryl)-9,10-bis(4-pyridylvinyl-2)anthracene (DAB) is a donor–acceptor-containing two-dimensionally cross-conjugated luminogen exhibiting the aggregation-enhanced emission effect, here we report its one- and two-photon absorption and fluorescence properties in different solvents and its solid-state piezofluorochromism. It is found that DAB exhibits strong solvatochromic effect and its two-photon absorption cross sections are solvent-dependent. The maximal two-photon absorption cross sections values measured in dichloromethane, tetrahydrofuran, and toluene solutions are 670, 1840, and 2030 GM, respectively. Piezofluorochromic experiment shows that the fluorescence color and emission spectrum of DAB solid could be changed reversibly between red (617 nm) and deep red (654 nm) emissions upon pressing and annealing. Powder wide-angle X-ray diffraction and differential scanning calorimetric analyses reveal that the Piezofluorochromic behavior is caused by the external stimuli-induced phase transformation between crystalline and amorphous states.