In this work, the mechanisms for creating a combined electronic–radiative local state beneath the conduction band, consisting of intrinsic and activator electron–hole states, are experimentally substantiated. In the first part of this work, the mechanisms of the formation of intrinsic and activator electron–hole trapping centers are experimentally demonstrated in all four matrices with activators. Intrinsic electronic states are localized on activators and anions of the matrix, forming intrinsic and activator electronic states. The hole component of the electron–hole pairs is localized near the activators. Thus, the energy of intrinsic electronic excitations localized in the matrix in the form of combined electronic–radiative states is observed at 3.06–3.1 eV and 2.92–2.95 eV. Radiative states are excited by photon energies of ~4.5 eV and ~4.0 eV, resulting in recombination emissions at 3.06–3.1 eV and 2.92–2.95 eV, as well as activator emissions at 2.06 eV for Mn2+, 2.5 eV for Tb3+, and 2.56 eV and 2.16 eV for Dy3+. Energy transfer from the matrix to emitters or activators occurs during the decay of the combined radiative state. Upon heating, electrons localized on anions and activators delocalize at temperatures of 200–350 K. The energy released during the recombination of an electron with a hole near the activators is transferred to the activators. This process facilitates energy transfer to activators in dosimeters and detectors.

The formation of new radiative states from the combination of Dy2+ - SO-4 and SO3-4 - SO-4 electron trapping centers in the range of 2.95-3.1 eV has been investigated using VUV and thermal activation spectroscopy. During the excitation process, there is a charge transfer between the oxygen ion of the sulfate anion and Dy3+ leading to the formation of a combined emissive state SO3-4 -> SO-4 . These states can be formed from the electron-hole trapping centers of Dy2+ - SO-4 and SO3-4 - SO-4 . The combined radiative state at 2.95-3.1 eV and impurity emission at 2.16 eV and 2.56 eV are excited simultaneously by photons of 3.95 eV and 4.5 eV, respectively. During the thermal or optical excitation process, the Dy2+ and SO3-4 electronic centers are ionized. Electrons recombine with a hole trapped by the ground state of the impurity (SO-4 - Dy3+), and the released energy is transferred to the Dy3+ impurities.

High-entropy garnet crystal structure compounds with novel chemical compositions (Y3-x-y-zCaxLiyLnzGa5-mAlmO12) (Ln – Ce, Eu, Tb) have been synthesized by an aqueous sol-gel method. The multinary substitution of yttrium by calcium, lithium and lanthanide element (cerium, europium and terbium) effects in these gallium/aluminium garnets have been investigated. The intermediates and synthesized end products were characterized by thermal analysis (TG/DTG/DSC), powder X-ray diffraction analysis (XRD), FT-IR spectroscopy and scanning electron microscopy (SEM). The different effects of multinary substitution with calcium, lithium and lanthanide ions in Y3-x-y-zCaxLiyLnzGa5-mAlmO12 samples in comparison with single-metal substitution cases were determined from the results of XRD analysis. The XRD patterns of these samples clearly showed that single phase cubic structure garnets have been synthesized at low substitutional level of yttrium by calcium, lithium and lanthanide element (cerium, europium and terbium). The luminescent properties of (Y3-x-y-zCaxLiyLnzGa5-mAlmO12) (Ln – Ce, Eu, Tb) garnets were also investigated.

The nature of the impurity emission and the process of creating intrinsic and impurity electron-hole trapping centers were studied by spectroscopic and thermal activation methods in Na 2 SO 4 -Pb and K 2 SO 4 -Pb phosphors. The combined radiative electronic state is formed from intrinsic SO 3− 4 - SO − 4 and impurity Pb + -SO − 4 electron-hole trapping centers in UV-irradiated phosphors with a photon energy of 6.2 eV at 80 K. Emissions of 3.2 eV and 3.6 eV resulting from irradiation with photons with an energy of 6.2 eV are associated with intracenter transitions of 3p 1 - 1s 0 in Pb 2+ located in nonequivalent positions of the Na 2 SO 4 lattice.

The mechanisms of formation of induced intrinsic and impurity radiative states, which consist of intrinsic and impurity electron–hole-trapping center states in irradiated Ca2P2O7−Mn and Ca2P2O7 phosphates, were investigated using thermoactivation and vacuum-ultraviolet spectroscopy methods. These centers are excited at photon energies of 4.0 eV and 4.5 eV, which are within the matrix’s transparency region. New radiative-induced states at 3.06 eV and 2.92 eV are demonstrated to be generated upon the excitation of anions by photons with energies of 5.0 and 5.64 eV. This process is due to charge transfer from the ion to the impurities, specifically Mn2+(O2−−Mn2+) and the neighboring ion O 2−−(P2O7)4−. Furthermore, upon the excitation of matrix anions with photon energies exceeding the band gap (8.0–8.25 eV), electron-trapping by impurities such as Mn2+ and (P2O7)4− ions results.

In the irradiated phosphor 4 LiRbSO Eu , the mechanisms of formation of the induced or combined electron-emitting state at 3.1-2.94 eV were studied using optical and thermal activation spectroscopy methods. It has been shown experimentally that the combined electron-emitting state of the phosphor is formed from the electron states of impurity and intrinsic electron and hole trapping centers of 24Eu SO   and 34 4 SO SO . Electron and hole trapping centers are created by irradiating the phosphor with photons exceeding the width of the forbidden band of the matrix, where free electrons are created in the conduction band and a hole in the valence band. The trapping center is formed by the capture of free electrons by impurities and anionic complexes according to the reaction 3 2 Eu e Eu      ,2 34 4 SO e SO    . In one process with electron centers, holes in the form of 24SO are localized. Thus, impurity and intrinsic 2 4Eu SO   and 34 4 SO SO  electron-hole trapping centers are formed. Similarly, trapping centers are formed as a result of charge transfer from the excited anion of the 24SO complex to the 3Eu  impurities and to the neighboring 2 4 SO anions according to the reaction ( 2 3 O Eu   ) and ( 2 24O SO  ), and localized holes are also formed in one act along with it. Combined electron-emitting states consisting of impurity and intrinsic electron states are excited by photons with energies of ~4.0 eV and ~4.5 eV.

Colloidal quasi-two-dimensional cadmium chalcogenide nanoplatelets have attracted considerable interest due to their narrow excitonic emission and absorption bands, making them promising candidates for advanced optical applications. In this study, the synthesis of quasi-two-dimensional CdSe NPLs with a thickness of 3.5 monolayers was investigated to understand the effects of synthesis temperature on their stoichiometry, morphology, and optical properties. The NPLs were synthesized using a colloidal method with temperatures ranging from 170 °C to 210 °C and optimized precursor ratios. Total reflection X-ray fluorescence (TXRF) analysis was employed to determine stoichiometry, while high-resolution transmission electron microscopy (HRTEM) and UV-Vis spectroscopy and photoluminescence spectroscopy were used to analyze the structural and optical characteristics. The results showed a strong correlation between increasing synthesis temperature and the enlargement of nanoscroll diameters, indicating dynamic growth. The best results in terms of uniformity, stoichiometry, and optical properties were achieved at a growth temperature of 200 °C. At this temperature, no additional optical bands associated with secondary populations or hetero-confinement were observed, indicating the high purity of the sample. Samples synthesized at lower temperatures exhibited deviations in stoichiometry and optical performance, suggesting the presence of residual organic compounds.

Quantum confined CdTe nanoplatelets (NPL) are synthesized in colloidal solutions. Formation, growth, and transformations of 2D NPLs are monitored using UV-visible absorption PL spectroscopy and transmission electron microscopy.The luminescence intensity of NPL dependences on temperature and injection of precursors are showed. It is found that the luminescence spectra shift to the long-wavelength region with increasing temperature, due to an increase in the thickness of the NPL. The dependence of the band gap from the thickness of NPL is shown. The band gap is determined by the thickness and number of layers. The dependence of the concentration of precursors in the reaction mass and the kinetics of NPL growth are shown. Excitation of defect states luminescence depends on the coordinating oleic ligand. The crystal structure of CdTe NPL analyzed by electron diffraction pattern (ED), which allows a comparative conclusion about the crystal structure of the obtained NPL samples.

The Na 2 SO 4 − Dy samples were obtained by slow evaporation method. The spectroscopic methods were used to study the mechanisms of formation of electron and hole trapping centers. Intrinsic recombination emission of 2.9–3.1 eV and impurity emission of 2.55 eV and 2.15 eV are excited at 4.0–4.5 eV. Intrinsic SO 3− 4 − SO − 4 and impurity Dy 2+ −SO − 4 trapping centers were revealed. The local levels corresponding between the electron and hole trapping center are 4.0–4.5 eV.

The creation of a combined radiative state at 2.95–3.1 eV in the phosphor CaSO4−Dy 3+ has been investigated using vacuum ultraviolet and thermoactivation spectroscopy methods. It is shown that the combined radiative electronic state is formed from the radiative electronic states of the impurity electronic trapping centers Dy 2+− SO4− and the intrinsic electronic radiative states SO43−−SO4− during the excitation of the anion complex SO42−, as a result of charge transfer from the excited anion complex O 2−−Dy 3+ to the impurities and the neighboring anion complex O2−− SO42−. In the CaSO4−Dy phosphor, the combined radiative electronic state and impurity emission of Dy 3+, 2.16 eV and 2.56 eV are excited by photons with energies of 3.95–4.0 eV and 4.5–4.6 eV. Energy transfer from the matrix to the Dy 3+ impurities is revealed upon thermal exposure as a result of the ionization of the electronic capture centers of Dy2+ and SO43−.

The Na 2 SO 4 samples were obtained by slow evaporation method. The mechanisms of the formation of electron and hole trapping centers are investigated by spectroscopic methods. Intrinsic recombination emission of 2.9–3.1 eV and impurity emission of 1.85 eV are excited at 4.0–4.5 eV. Intrinsic SO 3− 4 −SO − 4 and impurity Mn + − SO − 4 trapping centers were revealed. The local levels corresponding between the electron and hole trapping center are 4.0–4.5 eV. The decay of intrinsic and impurity trapping centers was recorded at temperatures of 130–150 K and 280–350 K.

Vacuum ultraviolet and thermal activation spectroscopies were used to study the nature of intrinsic emission and the mechanisms of the formation of electron and hole trapping centres in irradiated Li2SO4 powders and crystals. The obtained results along with excitation spectra showed that recombination emission at 3.8–4.2 eV and 4.5–5.5 eV occurs when an electron passes from the second and third sub-bands of the valence band formed from the 2p state of oxygen to the conduction band. It has been determined that Li2SO4 electron and hole trapping centres are created when electrons are trapped in the SO42– anionic sites. The holes are localised in the form of SO4 – radicals. The spectral position and intensity of individual emission bands are dependent on the crystallographic arrangement of localised holes.

Spectroscopic and thermoactivation methods were used to study the processes of accumulation of electron and hole trapping centers and energy transfer of electronic excitations to impurities in CaSO4-Mn and BaSO4-Mn. It is shown that electronic trapping centers are created during the excitation of an anionic complex as a result of charge transfer from O2−→SO42− to closely spaced anionic complexes SO42− in CaSO4 and BaSO4. In CaSO4 and BaSO4, energy transfer from the host to impurities occurs at the moment of charge transfer from the excited anionic complex to the combined radiative electronic state at 2.95–3.1 eV. This combined state is formed from electronic trapping centers Mn+-SO4− and SO43−-SO4−. It was found that the emerging combined radiative states at 2.95–3.1 eV of sulfates, which are formed as a result of charge transfer from the excited anionic complexes to the excited state of impurities, Tl+,Cu+,and Mn2+, occupy the same energy levels as the intrinsic electronic trapping center SO43− of the host at 2.95–3.17 eV. Experimental results show that during UV photon irradiation, anionic complexes are excited mainly near impurities in sulfates.

Quantum-confined CdTe nanoplatelets (NPL) are synthesized in colloidal solutions. The formation, growth, and transformation of 2D NPLs are monitored using UV-visible absorption PL spectroscopy and transmission electron microscopy. The luminescence intensity of NPL dependences on the temperature and injection of precursors is shown. It is found that the luminescence spectra shift to the long-wavelength region with increasing temperature due to an increase in the thickness of the NPL. The dependence of the band gap on the thickness of the NPL is shown. The band gap is determined by the thickness and number of layers. The dependence of the concentration of precursors in the reaction mass and the kinetics of NPL growth are shown. The excitation of defect states luminescence depends on the coordinating oleic ligand. The crystal structure of the CdTe NPL was analyzed via the electron diffraction pattern (ED), which allows a comparative conclusion about the crystal structure of the obtained NPL samples.

This article describes a new technique for postsynthetic doping/alloying of Mn into ZnSe nanocrystals. The key feature is that it employs diethyldithiocarbamate anion to selectively bind the host cations and promote ion exchange. The presence of Mn in the product is confirmed with photoluminescence (PL) and total reflection X‐ray fluorescence spectroscopy. The cation exchange reaction takes place at temperatures as low as 100 °C. Higher temperatures allow to incorporate the impurity in greater quantities; however, after a crossover temperature of ≈200 °C, the process gets convoluted with Ostwald ripening and sulfide deposition, as evident from electron diffraction data, high‐resolution transmission electron microscopy (HR‐TEM), and elemental analysis of the samples. Studies of PL lifetime and quantum yield confirm these findings. Preliminary success is also shown for other impurities: Fe and Co are present in the respective samples in ≈17 at% of total metal content.

The nature of electron-hole trapping centers in Na2SO4-Mn and K2SO4-Mnferroelectric crystals was studied by spectroscopic methods. It is shown that several types of impurity electron-hole trapping centers are created in such crystals under electrons and holes are localized at brokenlattice sites near the Mn2+ impurity.

Various variations of the synthesis of ZnSe quantum dots are investigated. The influence of temperature, the concentration of precursors and the time of synthesis of quantum dots was taken into account. Aliquot absorption spectra is measured for various time intervals and the dynamics of the growth of ZnSe quantum dots is estimated. Luminescence and absorption spectra were obtained for purified quantum dots. Based on the experimental data, the nucleation time of quantum dots, optimal methods of synthesis and growth control is determent. HRTEM images showed the average size of ZnSe quantum dot, the calculated band gap is 2.84 eV.

The nature of intrinsic emission and the creation of electron-hole trapping centers in irradiated with ultraviolet and X-rays at 15 K and 300 K was investigated in Li2SO4 by methods of spectroscopy. It is shown that in activated Li2 SO4 with an energy of 6 ÷12.4 eV, emission appears in a wide spectral range to excite rare earth ions that are used as UV sources. These same photons create electron-hole trapping centers as well.

В работе представлены результаты синтеза исходных кластерных соединений на основе халькогенидов кобальта и проведена их термодеструкция на углеродном носителе - саже VulcanXC-72, а также исследованы структурные и физико-химические характеристики приготовленных каталитических систем. Установлен оптимальный режим работы водородовоздушных топливных элементов (ТЭ), а также выявлено, что наибольшая эффективность работы топливного элемента достигается при одновременном воздействии этих факторов. Изучена роль каждого из этих факторов на повышение энергетических параметров ТЭ.

Two-dimensional (2D) CdTe nanoplatelets were synthesized using cadmium propionate, acetate and myristate precursors. Growth of nanoplatelets within the temperature range of 180-250 degrees C was monitored with optical absorption, PL spectroscopy and transmission electron microscopy. Continuous growth of NPLs was observed for hydrophobic propionate and myristate precursors at low temperatures, while in the presence of cadmium acetate Ostwald ripening occurs at high growth temperature. It is shown that zinc blende CdTe nanoplatelets with (00l) truncation axis grow by lateral expansion with oriented attachment mechanism. The presence of monomers is considered of major importance for oriented attachment. The growth conditions and duration time were opti-mized to provide homogeneous CdTe nanoplates.