| Abstract
| - We show that meso-to-meso ethyne-bridged (porphinato)zinc(II) oligomers (PZnn structures) define exceptional low band gap organic materials that possess both large magnitude NIR S1 → S0 fluorescence quantum yields and substantial S1 → Sn absorptive cross-sections, tunable over a wide 850−1400 nm spectral window. These PZnn species possess fluorescence quantum yields (φf values) comparable to the highest reported for NIR laser dyes in the 750−900 nm regime; importantly, these emitters do not suffer from commonly cited tricarbocyanine dye drawbacks of poor photostability and substantial φf sensitivity to solvent polarity. Furthermore, τo (kr-1) values determined using the Strickler−Berg method highlight the close correlation of fluorescence quantum yields with S0 → S1 integrated oscillator strength and demonstrate a rare if not unique example of broad NIR spectral domain fluorescence energy modulation, where φf magnitudes follow a simple Strickler−Berg relationship.
|
