Исследование оптических и люминесцентных свойств углеродных наночастиц методом микрофотолюминесценции

Abstract

The important features of the optical, luminescent, and emission properties of aqueous solutions of carbon nanoparticles (CNPs) of various types in the interaction of particles with electromagnetic radiation have been studied and analyzed. It is shown that the functional groups of CNPs play the dominant role in the spectra of optical absorption and photoluminescence (PL) of particles. Hydrothermal (HT) treatment of CNPs in the presence of ammonia and thermal treatment of particles in a solution of hydrogen peroxide have a strong influence on the absorption spectra, PL, and quantum yield (QY) of emission. It was found that the main PL bands of CNP samples are formed by superposition of several separate PL bands associated with electronic transitions of various types of radiative centers, and their excited states are located in the band gap of the carbon core of the particles. It was established that this circumstance is the reason for the dependence of the position of the PL band peak of most types of CNPs on the excitation wavelength. Linear dependences of the position of the PL band maximum and the emission QY magnitude on temperature and an exponential dependence on the time of HT treatment were revealed. The method of exposure to exciting radiation showed that the change in the PL intensity and the emission QY value under the influence of electromagnetic radiation is due to the photostimulated change in the surface recombination rate and diffuse particle processes in the region of excitation of CNP solutions. The possibility of investigating the stability of PL and QY by exposure of CNPs solutions to excitation radiation was demonstrated.