Triplet exciton reactions in MEH-PPV films registered by accompanying magneto-sensitive photoluminescence

Magneto-sensitive delayed photoluminescence (DPL) of the deaerated MEH-PPV films in the presence of an external magnetic field is investigated. The obtained results have shown that the sign of the magnetic field effect on DPL can be inverted by varying molecular oxygen concentration in the films. For explaining the sign -inversion of the magnetic field effect on DPL, the mathematical model based on the superposition of exciton-initiated reactions was proposed. The magnetic field dependencies of DPL based on the theoretical model were calculated. The calculations of the magnetic field effects on DPL confirm the sign-inversion effect. Also, the critical molecular oxygen concentration when the magnetic field effect on DPL disappears was determined theoretically. The obtained results can be used for the detection of spin-selective exciton-initiated reactions as well as for the determination of molecular oxygen concentration in MEH-PPV films.

Automated summary

The Magneto-sensitive delayed photoluminescence (DPL) of deaerated MEH-PPV films was studied in the presence of an external magnetic field. It was found that the sign of the magnetic field effect on DPL could be inverted by varying the molecular oxygen concentration in the films. A mathematical model based on the superposition of exciton-initiated reactions was proposed to explain the sign-inversion effect. Theoretical calculations of the magnetic field effects on DPL confirmed the sign-inversion effect and determined the critical molecular oxygen concentration when the magnetic field effect on DPL disappears.