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Information × Registration Number 0214U002563, 0113U004648 , R & D reports Title Mechanism of low-threshold noncoherent up-conversion in novel composite organic materials for optoelectronics. popup.stage_title Head Kadashchuk Andrey Konstantinovich, Registration Date 16-01-2014 Organization Institute of physics NASU popup.description2 The aim of the research project was the study of the nature of non-coherent up-conversion of light in model composite material. The comprehensive measurements of the steady-state absorption and emission spectra, the luminescence ones with pico- and nanosecond signal resolution at different temperatures within the wide range of excitation energy, and photo-induced absorption spectra by the pump-probe method with femtosecond time resolution were made for the model material composed of the matrix of the diphenile-antracene doped with the platinum complex of porphyrin, and for its components in solution and solids as well. As a result, there were obtained the data about the parameters of excited states for this composite and its components, and in the issue, the energy-level diagram was built and the scheme of energy transfer for optical excitations in the composite was proposed. In the films of this composite at the room temperature, the noncoherent up-conversion of light was revealed under the low-intensity excitation through the absorption band of admixture. At that, the up-converted emission was a delayed fluorescence of the diphenile-antracene matrix that arose due to effective triplet-triplet annihilation. The intersystem crossing in platinum complex of porphyrin was ascertained to pass very quickly for the time shorter than 80 fs, while the transfer of the triplet excitations from admixture molecules to matrix occurred during the tens of nanoseconds. There was found the rate of the triplet excitations' energy transfer in composite system to be dependent from the temperature and admixture concentration, at that the slowest and limiting stage of this process was the diffusion of the triplet excitations within the aggregates of the admixture molecules. It was shown, that the certain part of the excitations remains trapped within these aggregates and doesn't contribute to the up-conversion of light energy. Product Description popup.authors Вахнін Олександр Юрійович Кадащук Андрій Костянтинович Фіщук Іван Іванович popup.nrat_date 2020-04-02 Close