Peculiarities of photoprocesses in poly(9,9-di-$n$-octylfluorenyl-2,7-diyl) films doped with potassium iodide

The spectral-luminescence properties of poly(9,9-di-$n$-octylfluorenyl-2,7-diyl) (PFO) films doped with potassium iodide are investigated. It is found that the addition of potassium iodide at concentrations of 0.1–1% leads to a drop in the degree of ordering of the PFO films and decreases the fluorescence intensity and lifetime of the polymer. The kinetics of photoluminescence of PFO–KI films is studied in nano-, micro-, and millisecond time bands. Analysis of the experimental data on long-term luminescence using the percolation model showed that the addition of potassium iodide to the polymer increases the degree of disordering of the film. Investigations of the effect of an external magnetic field on the PFO luminescence over a wide time range indicate a complex character of the time dependence of the magnetic effect. The changes in both the magnitude and sign of the magnetic effect $g(B)$ are observed over the entire measured time range.