The recombination, or fusion, of triplet excitons (which are efficiently produced by singlet exciton fission at 300 °K) leads to an enhancement in the fluorescence quantum efficiency Φ at excitation light intensities I ≳ 1015 quanta-cm-2-sec-1 (366 and 436 nm wavelength). It is possible to fit a calculated Φ (I) curve to the experimental data if values of the triplet exciton lifetime τ = 4.6 × 10-6 sec, diffusion coefficient perpendicular to ab plane D⊥ab = 2.0 × 10-4cm2-sec-1, and diffusion length l⊥ >ab = 4.2 × 10-5 cm are used.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics