The preparation on micro/nano-particles of carbazole-chalcone derivatives and their aggregation-induced emission enhancement(AIEE)

We have synthesized three new chromophores containing carbazole as donor and o-pyridyl chalcone as acceptor and prepared micro/nano-particles.Based on SEM spectrum and UV absorption and fluorescence measurements,we have found that the more o-pyridyl chalcone and smaller particles in the aggregation that tends to the J-type aggregation.And the group of o-pyridyl chalcone has contribution to the aggregation-induced emission enhancement(AIEE).Steady and time resolution of fluorescence measurements indicate that chromophores in aggregation state have expanded fluorescence lifetime,accompanying with high quantum yield,in comparison with those in solution state.Thus,the radiative decay constants(kf) of chromophores in aggregate become increasing and the same time the nonradiative decay constants(knf) of chromophores in aggregate become decreasing,which results in the obvious the aggregation-induced emission enhancement(AIEE).