Efficient Two-Photon Absorption Materials Consisting of Cationic Dyes and Clay Minerals

Abstract

We systematically investigated enhancement of the molecular two-photon absorption (TPA) cross sections (σ(2)) of organic dyes confined in the interlayer space of clay films. Several possible mechanisms have been proposed to explain the enhanced TPA of dyes in the interlayer spaces of clays. The present study comprehensively investigates two of these mechanisms, namely, (1) enhanced molecular planarity and the consequent extension of the π-electron system and (2) enhanced molecular orientation. We fabricated transparent dye–clay films consisting of a synthetic saponite clay and four cationic dyes. Two of these dyes are expected to have enhanced planarity when they are hybridized with a clay mineral. The other two dyes are considered to retain the planarity of their conjugated π-electron systems when they are in solution or in the interlayer space of a clay. We experimentally measured the σ(2) of these dyes in a clay film and in solution and found that the σ(2) of all four dyes is enhanced in a clay film bu...