Features of deactivation of excited states of cationic polymethine dye in the matrices of halogen-containing derivatives of poly-N-epoxypropyl carbazole

Abstract

Singlet and triplet states of the cationic polymethine dye in polymers that are derivatives of poly-N-epoxypropyl carbazole with heavy atoms of different chemical nature were studied. It was shown that the presence of heavy atoms in the structure of the polymer leads to an appearance and rise of the dye phosphorescence due to the growth of the spin-orbit interaction in the dye molecule and increasing in the rate of singlet-triplet transitions. Also, the appearance of recombination luminescence indicated the formation and recombination of electron-hole pairs, which is an additional channel of relaxation of excited states of the dye in hole conducting polymer films. It was shown that external magnetic field leads to decreasing in the intensity of recombination luminescence. The time-dependent behavior of the magnetic effect is the result of competition between the singlet and triplet channels of the formation of the electron-hole pairs.