The two-photon absorption properties of anionic poly(phenylene ethynylene)-type conjugated oligo- and polyelectrolytes are studied in molecularly dissolved and aggregated forms in aqueous solution. Several different polyvalent cations are used to induce aggregation. It is found that both materials in the aggregated form exhibit enhanced two-photon excited fluorescence (2PEF) and two-photon cross section (σ₂) compared with the molecularly dissolved structures. The 2PEF and σ₂ are unaffected by the nature of the polyvalent cation that is used to induce aggregation. The two-photon absorption cross section enhancement arises because of the increase in the difference dipole moment (Δμ) in the aggregates of the conjugated materials, an effect that is attributed to the introduction of charge transfer character into the aggregate excited state.

中文翻译：

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阴离子共轭聚电解质的聚集增强双光子吸收。

以水溶液中的分子溶解和聚集形式研究了阴离子型聚（亚苯基乙炔）共轭低聚物和聚电解质的双光子吸收特性。几种不同的多价阳离子用于诱导聚集。据发现，这两种材料在聚集形式表现出增强的双光子激发荧光（2PEF）和双光子截面（σ ₂与分子溶解结构相比）。的2PEF和σ ₂它们不受用于诱导聚集的多价阳离子的性质的影响。由于共轭材料的聚集体中的差异偶极矩（Δμ）的增加而产生了双光子吸收截面的增强，这归因于将电荷转移特性引入聚集体激发态。