(a) Chemical structures of the conjugated polymers. (b) Photograph of the fluorescence from aqueous CP dot dispersions under two-photon excitation of an 800 nm mode-locked Ti : sapphire laser. (c) A typical AFM images of the PFPV dots on a silicon substrate. (d) Semilog plot of two-photon action cross-sections () versus the excitation wavelength for CP dots and rhodamine B (reference compound; with permission from [49]).
