Surface-Fixation Induced Emission of Porphyrazine Dye by a Complexation with Inorganic Nanosheets

This paper proposes a unique phenomenon of the strong enhancement in the fluorescence quantum yield (phi(f)) and the excited lifetime (tau) of tetra-cationic porphyrazine dye (Pz) upon a complexation with inorganic nanosheets. Although Pz does not strongly fluoresce in a bulk solution ((phi(f) = 0.01, tau = 0.1 ns), phi(f) and tau increased up to 19 and 34 times by an intercalation into stacked clay nanosheets. Steady-sate and time-resolved fluorescence measurements revealed that this strong enhancement in phi(f) and tau is derived from the suppression of nonradiative deactivation pathways of Pz by a complexation with day nanosheets. We here name this phenomenon a Surface-Fixation Induced Emission (S-FIE). S-FIE can be predicted easier than aggregation-induced emission (AIE) due to its clear mechanism depending on the flat solid surface, and we can thus simply design the photophysically enhanced system. Since photophysical characteristics of organic molecules directly influence the efficiency of objective reactions such as energy or electron transfers and photocatalysis, this study is beneficial to propose a novel strategy to create efficient photochemical reaction systems and photodevices.