**3.2 Picosecond time-resolved and steady-state spectral measurements**

The fluorescence lifetime measurements were performed with a streak camera (Agat SF 3M, VNIIOFI, Russia). A Nd:YAG laser with excitation wavelengths of 532 and 266 nm (the second and fourth harmonic of fundamental radiation) was used as a light source. The laser radiation parameters of the fluorimeter were as follows (for 532 nm): pulse energy 160 µJ, duration 20 ps (fwhm), beam diameter 5 mm. The error in determining the fluorescence lifetimes in time intervals of several nanoseconds did not exceed 5 %. In addition to the laser equipment, the Cary 100 spectrophotometer (Varian, Inc., USA) and the Cary Eclipse spectrofluorimeter (Varian, Inc., USA; slits width was 5 nm) were used for optical density measurements and fluorescence registration, respectively.
