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We provide comprehensive data on the spectral and temporal characteristics of low-frequency (LF) (MHz) and high-frequency (HF) (GHz) radio emissions and investigate their correlation with the streamer formation. We show that the propagation of streamers from the cathode is accompanied only by the LF radio emission (10-150 MHz). In contrast, the HF radio emission (1-4 GHz) arises during the travel of counterstreamers from the anode, which is also indicated by radio interferometric measurements. The power of the LF radio emission sharply increases almost synchronously with that of the HF radio emission. We find that the HF radio emission has a complex spectral and temporal structure and appears as multiple short (less than 1 ns) bursts characterized by various frequency components, existing in subnanosecond time intervals.

The results of the study of one-photon processes of optically induced degradation of photoluminescence intensity of CdS/ZnSe nanocrystals are presented, and mechanisms of this degradation are determined. It is shown that the nanocrystal photodegradation process consists of three components. The first degradation component is caused by Auger recombination activation in photoinduced hole trapping by the trap associated with a surface state; a long-term degradation component can be associated with thermally activated chemical bond breaking between a passivating ligand, i.e., oleic acid, and the nanocrystal surface followed by nonradiative recombination channel activation.

Luminescence characteristics of Nd3+ coordination compounds with pyrazole-substituted 1,3-diketonate ligand environment in KBr micropellets are studied. The luminescence decay times and the external quantum efficiencies are measured, intrinsic luminescence lifetimes of the Nd3+ ion in the complexes are estimated. The luminescence characteristics of the complexes in KBr micropellets and in DMSO solutions are compared.

Four novel 1,3-diketonate Eu 3 + complexes bearing pyrazole moieties as main ligands and a 4,7-Diphenyl-1,10-phenanthroline (bathophenanthroline) ancillary ligand were synthesized. The number of fluorine atoms in the main ligand was varied from 3 to 13. From spectroscopic studies of the synthesized complexes we conclude that increasing the degree of fluorination results in a significant rise in the quantum yield and sensitization efficiency. With further extension of the fluorinated chain length, saturation of these characteristics was observed. The maximum obtained values of the quantum yield and sensitization efficiency were 56% and 99%, respectively. In order to reveal the potential of the complexes for OLED applications, electroluminescent devices based on these compounds were fabricated and their performance was studied. It was found that the quantum efficiencies of the OLEDs and the sensitization efficiencies exhibit similar behaviour depending on the degree of fluorination of the ligands in the complexes.

In this study, two novel Pr

We studied luminescent properties of two Nd 3 + complexes with two different ligands. The first one was 1,3-diketone bearing a pyrazole fragment and the second ligand was either 1,10-phenanthroline or EtOH. For the ligand environment composed of 1,3-diketone and 1,10-phenanthroline the position of the hybrid triplet level was as low as 18200 cm − 1 . The spectral features specific to Nd 3 + emission observed in the photoluminescence spectra of the complexes under optical excitation provided the evidence for ion-centered luminescence. Radiative transitions were identified using the obtained spectroscopic data. Corresponding diagram of the energy levels of the complex with 1,10-phenanthroline ligand was developed. Possible energy transfer pathways were discussed.

We performed spectroscopic investigations of four novel Sc(III) metal-organic complexes with β -diketonate ligands. It was demonstrated that bonding the ligands with an optically passive Sc(III) ion leads to sensitization of the luminescence of the complexes and affects their optical absorption spectra. Luminescence decays of the complexes exhibit non-exponential behaviour. From spatially-resolved decay measurements we evaluated the number of different sites responsible for the luminescence in the investigated complexes. Small variations of the ligand structure significantly affects the wavelength of emission maximum. This phenomenon may occur due to the difference in crystal packing of the complexes or formation of charge-transfer states.

The luminescent properties of hybrid nanostructures constructed from colloidal quantum dots (QDs) of CdS passivated with thioglycolic acid, europium(III) tris(tenoyltrifluoroacetonate), and methylene blue dye molecules are studied. Spectral features typical for the formation of core/shell QDs of the CdS/CdS:Eu3+ type are found. It is noted that the adsorption of the europium complex at the QD interfaces and the formation of QDs of the CdS/TGA/Eu3+ are probable. Spectral patterns that reveal nonradiative energy transfer from the recombination luminescence centers of CdS QDs to the Eu3+ ions in the CdS/CdS:Eu3+ and CdS/TGA/Eu3+ structures are obtained. This is manifested in quenching the recombination luminescence of QDs and in the ignition of the intracentric luminescence of Eu3+, which enhance with an increase in the concentration of the europium complex. When such structures are combined with methylene blue molecules, the half-width of the absorption spectra is found to increase by 10–15% with an unchanged position of the absorption band maximum. With an increase in the concentration of methylene blue molecules, decreases in the intensity of the recombination luminescence band of CdS QDs at a wavelength of 530 nm and in the luminescence intensity of Eu3+ ions and simultaneously the rise up of the fluorescence of methylene blue at a wavelength of about 675 nm are observed. At the same time, a decrease in the luminescence lifetime of the bands of QDs and europium ions are observed. It is concluded that the nonradiative excitation energy transfer from both the recombination luminescence centers and Eu3+ ions to methylene blue molecules takes place.

New (2-(4-methylpyrazol-1-yl)phenyl) platinum(II) (dibenzoylmethane) Pt(mpp)(dbm) complex based on 4-methylpyrazole was synthesized using a simple scheme. Its crystal structure, spectral and electrochemical properties were studied. The extra pure green (CIE chromacity coordinates X = 0.1419, Y = 0.7444) electroluminescence for OLED structures was obtained.

Five novel europium β -diketonate complexes containing a pyrazole fragment were investigated. The influence of the number of fluorine atoms in diketonate ligands on luminescent properties was analyzed. Luminescence intensity of Eu 3 + complexes increases significantly when CH bonds with high oscillation energy are replaced with CF bonds with low oscillation energy as the efficiency of energy transfer is improved. Further extension of the fluorinated chain length results in a substantial decrease in non-radiative relaxation rates while the increase in luminescence decay rates is observed. The theoretical results elaborated in terms of Judd-Ofelt theory are in good agreement with the experimental data obtained by time-resolved luminescence spectroscopy.

We present the results of experimental investigations of supercapacitors produced by Panasonic using several methods, namely, measurements of temporal dependences of charging–discharging currents, cyclic dc charging, and cyclic voltammetry. The values of the internal resistance, static and dynamic capacitance, as well as their dependences on the bias voltage of the capacitors, have been determined. Measurements have shown that the initial stage of relaxation of current is well approximated by the exponential time dependence, and then transition to a powerlike dependence occurs. This well-known effect is explained on the basis of the allowance for specific transport properties of a porous fractal-type medium. These processes are adequately described by the fractional-differential model of anomalous diffusion. A weak dependence of relaxation curves on the voltage at low values of the latter ( 3 V) is explained by the appearance of new percolation paths blocked at low charging voltages due to the presence of high-potential barriers. The internal resistance and the static capacitance have been determined by measuring the voltage across the supercapacitor in the mode of dc charging. These parameters have been shown to depend on the voltage applied to the capacitor. The dependence of the dynamic capacitance on the voltage has been determined using cyclic voltammetry. It has been shown that the capacitance depends not only on the voltage, but also on the prehistory of charging and discharging of the capacitor. Comparison of the experimental results and the published data on the models and equivalent circuits with passive R, L, and C elements allows one to conclude that such models and equivalent circuits can be applied only when explaining a limited number of phenomena, in particular, behavior at small relaxation times.

In this study, two novel Pr 3 + complexes with different 1,3-diketonate ligands were synthesized and investigated. To study the effect of the ancillary ligand on the energy transfer mechanisms in the complexes, a phenanthroline ligand was introduced. To take into account the influence of the ligand environment composed of different ligands on the energy transfer and relaxation processes, we compared the synthesized compounds with a similar complex containing the phenanthroline ligand. The spectroscopic studies in the visible and near-infrared spectral regions were supplemented with DFT and TD-DFT calculations. We found two ligand-to-ligand charge transfer (LLCT) states, with one state corresponding to energy transfer between 1,3-diketones and the other – to energy transfer from the 1,3-diketone to the phenanthroline motif. It was demonstrated that optical excitation via the latter channel leads to a fourfold increase in the luminescence quantum yield as compared with excitation via the π - π ∗ transitions in 1,3-diketones. Moreover, both LLCT states provide sensitization of the Pr 3 + luminescence involving the 3 P 0 and 3 P 1 levels.

We studied luminescent properties of Pr 3 + complex with pyrazole and 1, 10-phenanthroline ligand environment. It was demonstrated that the complex exhibits so-called “antenna” effect which involves the electronic excitation transfer from the ligands to the rare-earth ion. The observed complex structure of the luminescence spectrum specific to Pr 3 + indicates that in the investigated compounds the luminescence originates from the rare-earth ion exclusively. The obtained data provided a means to identify the electronic transitions in the ion and to develop the corresponding energy diagram. Fluorescence lifetime imaging revealed uniform distribution of luminescence decay times for the Pr 3 + complex crystalline phase. Consequently, the Pr 3 + complex under study has one type of emission sites.

The efficiency of electronic-excitation energy transfer from organic semiconductor TPD to CdSe/CdS/ZnS nanocrystals passivated with different organic ligands is investigated. It is shown that the rate of energy transfer from TPD to nanocrystals decreases with increasing thickness of the passivation coating. It is suggested that the Forster mechanism is responsible for the excitation transfer.

Two new Sm

The interaction of PrCl3 with 1,3-bis(1,3-dimethyl-1H-pyrazol-4-yl)-1,3-propanedione in aqueous ethanol in the presence of a base and 1,10-phenanthroline was studied. It was shown that the composition of the products was dependent on the reaction conditions. The solvate [Pr(L)3(Phen)]•3PriOH crystallizes in a monoclinic crystal system (P21/c space group, a = 12.2239(12) A, b = 20.3403(19) A, c = 26.134(3) A, β = 102.380(2)° at 150 K). Absorption spectra of the complex in solution, as well as the spectra and the kinetic parameters of photo-luminescence were investigated.

We present a composite material based on polymer matrices doped with a new europium(III) complex exhibiting high quantum yield. The Eu(III) complex was introduced into two types of polymer matrices. We investigate the concentration influence of the complex embedded into polymers on luminescent properties of the composite material. This Eu(III) complex proved to be highly dispersible in polymers and compatible with ink-jet technology.

We report on the results of analysis of the kinetics of charge–discharge current of Panasonic supercapacitors in a wide range of time from 10–1 to 104 s. The non-Debye behavior of relaxation observed earlier by us and other authors is confirmed experimentally, and the influence of the supercapacitor charging regime on this process for various previous histories (values of applied voltage, charging time, and load resistance) is analyzed. The results are compared with available experimental data for paper–oil and electrolytic capacitors and with the results of calculations in the linear response model. It is found that in contrast to conventional capacitors, the response of the supercapacitor under investigation to variations of the charging regime does not match the linear response model. The relation of this nonlinearity to processes in the double electric layer, the morphology of the porous electrode, and the effect of charge reversal in pores is considered.

Fractional derivative formalism is proposed as the mathematical foundation of the polarization-depolarization current method for the diagnosis of dielectric isolation. Physical basis of the new approach is the observed deviation of the long-term relaxation from the Debye exponential law. We found that this behavior is consistent with the solution of the fractional differential equation: exponential behavior turns into the power dependence in the long-time asymptotics, and this part of the relaxation curve is more sensitive to the material state. The results of calculations for the polarization-depolarization currents in an oil-paper capacitor are in agreement with the specially performed experiments.

A series of novel highly NIR-emitting Nd 3 + complexes with specially designed 1,3-diketones bearing a pyrazole moiety and a linear C x F 2 x + 1 group ( x = 1 , 3 , 6 ) was obtained and exhaustively investigated. It was demonstrated that for the complexes with an increased number of fluorine atoms, the triplet level energy of the ligands is decreased and phonon relaxation processes are suppressed. This provides a remarkable increase in the photoluminescence quantum yield up to 1.1%, which is close to the highest values reported for Nd 3 + complexes with 1,3-diketones. The photoluminescence spectra of the complexes exhibited the Stark splitting indicative of non-cubic symmetry. Low symmetry of coordination environment was confirmed by the X-ray structural data and analysis of calculated Judd–Ofelt intensity parameters. Besides, it was revealed that the most intense band in the PL spectrum is attributed to the 4 F 3 ∕ 2 → 4 I 9 ∕ 2 transition (at 880 nm) which is commonly rather weak for simple diketonate complexes. The calculations showed that the unexpectedly high branching ratio of the 4 F 3 ∕ 2 → 4 I 9 ∕ 2 transition raises with elongation of the fluorinated chain and reaches 59% for the complex with x = 6 . The studies were conducted for solutions of the complexes as well as for solid samples, and the corresponding changes in their optical behavior were discussed. Uncommon properties of the synthesized Nd 3 + complexes make them promising materials for various state-of-the-art luminescent applications, e.g., luminescent markers with an unusual spectral intensity distribution. Based on the electroluminescence studies, we also estimated the potential of the complexes for purely NIR-emitting OLEDs fabrication.

A novel, to the best of our knowledge, approach to the design of the single-photon sources emitting in the spectral regions of 1060 and 1337 nm was developed. A unique hybrid structure based on colloidal CdSe/CdS/ZnS nanocrystals and neodymium(III) 1,3-diketonate was created. Direct energy transfer from the CdSe/CdS/ZnS single nanocrystal to the near-infrared (NIR) luminescent Nd(III) complex was observed and investigated by spectroscopic methods. The single-photon emission mode was confirmed for the novel hybrid source by Hanbury Brown and Twiss experiments.

Two new Sm3+ complexes with pyrazolic β-diketones bearing a CF3 group acting as main ligands and with 2,2’-bipyridine or 1,10-phenanthroline being the ancillary ligand were studied, and their energy level structure was established. Stark splitting observed in the photoluminescence spectra of the complexes points to their non-cubic symmetry, confirmed by the calculated Judd-Ofelt intensity parameters. Internal quantum yields obtained for the compounds by the Judd-Ofelt calculations were of the order of 5.5%, whereas the measured external quantum yields were 0.75% and 1.5% for Sm3+ complexes involving 2,2’-bipyridine and 1,10-phenanthroline ancillary ligands, respectively, with the corresponding sensitization efficiencies calculated as 0.16 and 0.26. It was demonstrated that replacing the 1,10-phenanthroline ancillary ligand with 2,2’-bipyridine provides an increase in the intensity of 650 nm emission of the Sm3+ complexes, with the branching ratio reaching 55%. Intensive emission of the studied complexes at 650 nm offers hope for their use as spectrally pure red emitters.

We performed spectroscopic investigations of a novel tris(1,3-bis(1,3-dimethyl-1H-pyrazol-4-yl)propane-1,3-dionato)(1,10-phenanthroline) holmium (III) complex. It was demonstrated that bonding the corresponding ligand environment to Ho

We have successfully synthesized Eu-based luminophores promising for inkjet printing with almost 100% efficiency of energy transfer from ligands to the lanthanide ion. The luminophores with β-diketonate ligands are characterized by means of optical spectroscopy. We reveal the impact of different types of β-diketonates on the quantum yield of luminescence and determine a β-diketonate complex exhibiting the highest luminescence quantum yield and promising for organic light-emitting diode (OLED) applications. We discuss the reasons for decreasing quantum efficiencies of other types of investigated ligands.

With the use of a novel thermoluminescence technique, a new type of surface traps is observed in colloidal CdSe nanocrystals of planar geometry (nanoplatelets). The emptying of these traps, which cannot be detected by means of the conventional thermally stimulated luminescence scheme, proceeds via a cascade process involving their own excited states. An energy-level diagram of nanoplatelets taking into account the specific characteristics of these traps is proposed and the density of surface states, featuring two peaks at energies of 100 and 280 meV, is determined.

Nanostructures in the form of 1.2-nm-thick colloidal CdSe nanoplatelets rolled into scrolls are investigated. The morphology of these scrolls is analysed and their basic geometric parameters are determined (diameter 29 nm, longitudinal size 100 – 150 nm) by TEM microscopy. Absorption and photoluminescence spectra of these objects are recorded, and the luminescence decay kinetics is studied. It is shown that the optical properties of CdSe nanoscrolls differ significantly from the properties of CdSe quantum dots and that these nanoscrolls are attractive for nanophotonic devices due to large oscillator strengths of the transition, small widths of excitonic peaks and short luminescence decay times. Nanoscrolls can be used to design hybrid organic–inorganic pure-color LEDs with a high luminescence quantum yield and low operating voltages.

Luminescence properties of hybrid associates of semiconductor colloidal CdS quantum dots (QDs) with an average diameter of 2.5 nm and methylene blue (MB+) cations were investigated. Their photoluminescence spectra, excitation spectra and luminescence decay spectra recorded using the time-correlated single photon counting techniques were analyzed. The increase of efficiency of MB+ fluorescence at 405 nm excitation was found. It corresponds to the absorption region of CdS QDs. When [ n CdS QDs ] : [ n MB + ] concentrations ratio changes from 100:1 to 1:3 for associates, then a decrease in the intensity of CdS QDs luminescence band (580 nm) and its increase for MB+ band (674 nm) were observed. At the same time it was found that the average lifetime of CdS QDs luminescence is shortened and the lifetime of MB+ luminescence becomes significantly longer. It was concluded that dynamic quenching due to nonradiative resonance energy transfer takes place. The efficiency of this process was estimated and the corresponding rate constant was calculated. It is 5.6 × 10 7 to 8.6 × 10 7 s − 1 .

The hole conductivity in films of three compounds, complexes based on europium β-diketonates, deposited by vacuum evaporation is studied by the time-of-flight technique. It is shown that no carrier photogeneration is observed in films under pulsed excitation with 337 nm light. The introduction of pentacene-based photogeneration layers into the samples made it possible to observe transient-current curves. It was found that a dispersive component of the transient current, associated with hole transport, is observed in a complex of europium with an auxiliary ligand based on bathophenanthroline. These data were used to determine the hole mobility. No dispersive component of the transient current was observed in complexes with an auxiliary ligand based on phenanthroline. A conclusion is made that the latter is due to the low mobility in compounds of this kind. This is attributed to a decrease in the degree of conjugation of the aromatic system, which occurs on passing from bathophenanthroline to phenanthroline.

It was demonstrated that bonding Eu3+ ion to β – diketonate ligand as main ligand and 4,7-Diphenyl-1,10-phenanthroline (bathophenanthroline) as ancillary ligand leads to a significant increase of extinction and luminescence intensity. To order the potential of this complex to OLED application, we fabricated and investigated the electroluminescent device based on this compound. We achieved a high value of photoluminescence quantum yield (56 %) and external quantum efficiency value of 1% at 12 V.

The temperature dependence of the photoluminescence intensity of colloidal CdSe nanocrystals having 5 nm in diameter was studied. It was demonstrated that the photoluminescence intensity exhibits a hysteresis at temperatures below 220 K. This effect was explained by a model taking into account formation of an additional nonradiative relaxation channel associated with Auger recombination promoted by hole trapping on the surface of the nanocrystals. The activation energy of the hole release process obtained in the framework of the model was 0.7 eV.

The temperature dependencies of the luminescence spectra of 5-nm-diameter CdSe semiconductor nanocrystals synthesized by colloidal-chemistry methods are investigated. The two bands observed in these spectra around 2.01 and 1.37 eV correspond to band-to-band transitions and luminescence of defect states, respectively. A model explaining the temperature behavior of the luminescence band intensities both upon cooling and heating is put forward. A new modification of spectrally resolved thermostimulated luminescence technique making it possible to determine the activation energies and the character of traps responsible for the temperature dependence of the luminescence intensities is suggested. This technique is used to obtain the activation energies of the emission and capture of electrons at traps (190 and 205 meV, respectively) and to determine the depth of the electron level (57 meV) responsible for luminescence in the 1.37-eV region.

The effect of the polymer matrix on luminescence properties of the europium complex we synthesized is studied. It is shown that the interaction of complex molecules with the matrix has practically no effect on the photoluminescence spectrum shape. The excited state lifetime decreases no more than twice.

The statistics of luminescence from single CdSe/CdS core/shell semiconductor nanocrystals under CW laser excitation at room temperature is experimentally investigated by recording sequences of absolute arrival times of the emitted photons. It is shown that the correlation coefficient for consecutive intervals between the photon-arrival times differs from zero. The correlation persists for photon-arrival intervals separated by two or more photon-detection events, until the time between the two intervals becomes, on average, as long as 180 ms, which corresponds to about 103 detected photons. A simulation of the luminescence process supports the conclusion that this correlation is linked to the blinking character of the quantum-dot luminescence.

A new scheme of the experimental setup for measuring the carrier mobility in thin films of organic semiconductor materials was proposed. Major factors controlling the time of exponential relaxation of the measuring system were analyzed. On this basis, conclusions were made on operating parameters of the measuring equipment required to reduce as much as possible the relaxation time. According to this, a new setup was developed. A qualitative improvement of current kinetic curves for a control sample was experimentally shown using the new setup. This allowed determination of transit times and carrier mobilities with high reliability.

We study 3D globular photonic crystals based on synthetic opals filled with semiconductor core/shell quantum dots CdSe/CdS by measuring the photoluminescence spectra. The spectra were obtained using 369, 384, and 408 nm LED light excitation and involving a pulse YAG laser operating at 365 and 266 nm. The study shows that the photoluminescence spectra of opal filled with CdSe/CdS changes sufficiently in comparison with spectra taken for pure opal and a reference colloidal solution of CdSe/Cds quantum dots in toluene. Such opals may be used to fabricate a narrow-band light sources.

We have studied the CdTe/CdSe tetrapod-shaped nanocrystal heterostructures with the use of photoluminescence spectra measurements and time-correlated single photon counting technique. The tetrapods were grown to have CdTe arms with different thickness of the CdSe shell. We have observed non-exponential photoluminescence decay of excited tetrapod-nanocrystals and proposed kinetic theory based on the branched crystal morphology and on the assumption about a potential barrier in the junction point of tetrapod. Analysis of studied nanocrystal behavior gives an evidence for tetrapods to behave as four weakly connected quantum wells. This interesting effect might find applications in nanoelectronics.

Experimental study of the hole mobility in polyvinylcarbazole (PVK) films doped with two kinds of nanocrystals, on bare core CdSe and core-shell CdSe/CdS quantum dots, with concentrations ranging from 3 · 1010 to 3 · 1015 cm−3, is presented. The quantum dots investigated were made using colloidal chemistry. The hole mobility was measured using the time-of-flight technique as a function of the applied electrical field in the range 105–106 V/cm and for temperatures from 20°C to 50°C. The transient curves, being featureless on a linear plot, show on a double logarithmic scale a sharp inflection point indicating a dispersive carrier drift process. The recovered values of the mobility are in the range 3 · 10−8–10−6 cm2·V−1·s−1 and their field and temperature dependences can be analyzed formally within the framework of the Gaussian disorder model proposed by Bassler. The energetic disorder is, within the experimental accuracy, independent of the concentration and type of quantum dots for the CdSe quantum dots at all concentrations and for the CdS/CdSe quantum dots up to 1014 cm−3. The spatial disorder factors are very large (from 5.3 to 8.7) and do not depend in a systematic way upon the type and concentration of quantum dots (QDs). The experiments show that the apparent mobility does not change considerably with concentration, but it was found that the samples with CdSe/CdS quantum dots at concentrations from 1015 to 3 · 1015 cm−3 show a decreased photocurrent response. The dependence of the time-integrated transients (corresponding to the full charge value) upon the quantum-dot concentration has been determined. Differences in total photogenerated charge for pure and doped polymer films imply that the quantum dots of that type are the hole traps with capture times much more smaller than the transit time and with emission times a few orders longer than the transit time. CdSe quantum dots without a shell do not seem to exhibit the same properties as core shells and do not produce considerable changes in the charge transfer, even at a density of 1015 cm−3.

It is shown that the finite-term representation of current relaxation in supercapacitors with a set of exponential functions fails to approximate it at long time, meanwhile the one-term approximation with the stretched fractional exponent gives a good agreement with experimental data both at short- and long-time asymptotics.

Spectral properties of hydrophilic associates of colloidal CdS quantum dots (QDs) with methylene blue molecules (MB) prepared by sol–gel method have been studied. The two basic types of hybrid associates were found using FTIR spectra technique. The first-type associates are characterized by planar location of MB heterocycle on QDs spherical interface. In this case MB dimerization is not observed. Both nitrogen and sulfur heteroatoms and double =N+–(CH3)2 bonds of MB are participants of association which causes to conformation of MB heterocycle and π-conjugation length decrease. In UV–Vis absorption and luminescence spectra blue shift of MB peaks for QD-MB associates in comparison with MB spectra in solutions and gelatin was found. The second type of association mostly involves MB nitrogen heteroatoms and CdS QDs interface atoms. At the same time, peaks of UV–Vis and luminescence spectra are red shifted. In this case, dimerization manifestation of MB in QD-MB associates was found. Using the time correlated single photon counting technique resonance electronic excitation energy transfer from recombination luminescence center of CdS QDs to MB molecules was found. Its efficiency is in the range of 0.36–0.51.

The temperature dependences of the thermostimulated capacitance and the voltage dependences of the transconductance were measured for heterostructures based on InGaN Solid solutions. Based on these data, the energies of deep centers, which can participate in the recombination flux formation in these structures, were determined.

CdS colloidal nanocrystals with an average size of 4.5 nm and oleic acid as surfactant were studied using photoluminescence spectroscopy and time-correlated single photon counting technique at different temperatures. Observed spectra revealed three thermally activated luminescence bands at 2.15, 1.76, and 1.37 eV in addition to conventional band edge recombination of the nanocrystals. We present a kinetic model based on concept of single emitters which quantitatively describes the luminescence of the ensemble of the nanocrystals in the temperature range 10–300 K. We determined activation energies (18.2 and 8.6 meV) for transitions responsible for the luminescence. The 1.76 eV band most probably emerges from the intrinsic defects on the surface of CdS, whereas bands at 2.15 and 1.37 eV result from the influence of oleic acid bonded to the surface of the nanocrystals.