https://orcid.org/0000-0002-4007-6291 Аннотация Предмет исследования. Представлены результаты исследования люминесцентных свойств органических светоизлучающих диодов на основе новых люминесцентных соединений, содержащих кумариновый фрагмент.
The effect of an external electric field on the luminescence characteristics of silver sulfide nanoparticles embedded in a film based on an optically passive dielectric matrix has been studied. The luminescence characteristics were studied using methods of optical and time-resolved spectroscopy involving the time-correlated single-photon counting technique. The morphology of the nanoparticles was studied using transmission electron microscopy. It was shown that in an external electric field, an increase in the intensity of the recombination luminescence band is observed for silver sulfide nanoparticles, together with an increase in the electronic relaxation rate. This effect is explained by the fact that the electric field enhances the transport of free holes to electron traps which are radiative recombination centers. The observed effects indicate that silver sulfide nanoparticles can be effectively used as active layers of organic lightemitting diodes, where an external field of the order of 500 kV/cm will not lead to a deterioration in their operating luminescence characteristics.
The paper studies the effect of external electric field on the optical properties of the spherical Ag2S quantum dots. Colloidal Ag2S nanoparticles passivated with 2-mercaptopropionic acid were obtained by photoinduced synthesis in the ethylene glycol. The nanoparticles shape and characteristic size were determined using the transmission electron microscopy. To analyze the external electric field influence, a series of samples was prepared based on the optically passive polymer film, where the nanoparticles were embedded. The films were placed between two glasses coated with the transparent electrodes based on the indium tin oxide (ITO). Intensity value of the external electric field created in such structures reached 500 kV/cm. The photoluminescence signal was registered using the CCD fiber spectrometer with spectral resolution of 1.16 nm. Spectrally resolved nanoparticles photoluminescence kinetics was measured by time-corre-lated counting of the separate photons. It was found that the presence of a field led to an increase in intensity and rate of the photoluminescence relaxation due to the surface states. This fact is related to acceleration of the free holes transportation to the recombination centers in the external electric field. It is shown that under long-term exposure to laser radiation with a wavelength of 405 nm and the average power of 5 mW, the nanocrystal photoluminescent properties could degrade, as it occurs due to formation of new centers of non-radiative recombination and photoionization of the quantum dots
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