TAILOR-MADE CONTROL OF FLUORESCENCE IN AN ARRAY OF POLYMER NANOSHEETS FOR OPTICAL MEMORY APPLICATION

Abstract

In this study, we describe tailor-made control of fluorescence intensity in an array of polymer nanosheets assemblies by combining energy transfer with electron transfer process. The assemblies were made of three-type polymer Langmuir-Blodgett films. The first layer contains phenanthrene chromophore, the second layer contains anthracene chromophore, and then the third layer having dinitrobenzene unit is assembled. The phenanthrene(Phen)layers play a role of energy donor of the anthracene(An)layers under light excitation(λex = 298 nm), and the dinitrobenzene(DNB)layers function as an electron acceptor of the anthracene layers. As the phenanthrene layer was excited byλex = 298 nm, the excited energy was transferred selectively to anthracene layer. Subsequently, the dinitrobenzene layer quenches the excited state of anthracene by electron transfer reaction. As the result, weak fluorescence was observed from the nanosheets. However, when the photocycloaddition of the anthracene molecules proceeds by 368 nm irradiation the efficiency of energy transfer from phenanthrene to anthracene decrease. As a result the phenanthrene fluorescence was recovered. The phenanthrene emission can be controlled in a tailor manner by 368 nm irradiation. This tailor-made control can be applied to luminescence-based optical memory.