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The ion-implantation of silica is widely used in optoelectronics and neighboring areas. Si + ions serve for formation of clusters/nanocrystals in components of microelectronic devices; Ge+, P+, and B+ are used for controlling refraction index in lightguides. All enumerated ions interact chemically with oxygen atoms in SiO2, thus shading the stoichiometric distortions caused by direct impact interactions of particles with a host. In this research, the optically-active defects in the silica network were induced by embedding of chemically inert Ar + ions and thermal neutrons. A set of bands belonging to neutral oxygen vacancies (≡Si-Si≡), non-bridging oxygen hole centers (NBOHC) and some other point defects were detected in the photoluminescence spectra of implanted/irradiated samples. The intensity variation of the bands at the Ar + fluence increase was found to be caused by a competition between defect nucleation and their annealing or/and concentration quenching at high fluence. The ionization of atoms by charged particles resulted in the multivariant spectral manifestation of the defects of the same type due to their arrangement in differently distorted host localities. The diversification of defects produced by neutrons was lesser, because the neutron impact on the silica host was limited by the interactions with nuclei.

In contrast to damage accumulation in rocks subjected to constant or growing load wherein local failures increase with time, the strongest fracture events at the shock forcing occur at the very beginning of the loading. An inverse trend in the stress variation could be expected to affect some parameters of the rock behavior specific for a quasi-static pressure exposure. In this study, shock waves in uniaxially compressed granites were generated by an electric discharge, and the nucleation of microcracks was detected by the acoustic emission (AE) method. The experiment represented some conditions, under which deep underground rocks response on the impact forcing (explosions, shocks, etc.). The compression varied from zero to a pre-damage level. Fine-grained Sesam Black granite (grain size ∼1 mm) and coarse-grained Rapakivi granite (5–7 mm) were tested. The energy release distributions in all AE time series followed a Gutenberg-Richter type relation (power law) in both compressed and free samples with a departure from the log-linear dependences for the most intensive AE peaks. At the same time in a compressed fine-grained sample, a high-energy reminder of the power law distribution followed a well-defined exponential (Poisson-like) function; in coarse-grained granite, the higher-energy part of the energy distribution could not be described with any explicit expression. The specificities in the mechanical behavior of the tested fine- and coarse-grained granites were considered from the viewpoint of the hierarchical structure of rocks.

Solution-processed hybrid perovskite materials are attracting considerable attention as active layers of solar cells and hybrid light-emitting diodes (LEDs). Introducing perovskite CsPbBr3 nanocrystals (NCs) into light-emitting polymer (MEH-PPV) matrix can improve the processability and stability of such hybrid LEDs. In this work we investigate experimentally and consider theoretically the nonradiative excitation energy transfer from perovskite CsPbBr3 NCs to organic conjugated polymer MEH-PPV matrix along with experimental investigation of optical properties of such MEH-PPV:CsPbBr3 hybrid thin film structures. The theoretical analysis is carried out based on the Forster theory. The relative photoluminescence (PL) intensity of the MEH-PPV matrix is calculated as a function of the embed CsPbBr3 NC concentration. The decrease of the PL intensity with the increase of the CsPbBr3 NC concentration is found both theoretically and experimentally. It was found that the PL decay obtained experimentally is stronger with respect to that found theoretically. The reasons for the quantitative distinctions between the experimental data and as a result of the theoretical consideration are discussed.

IR windows made of ZnS ceramics serve as protective elements for the thermal imaging systems established on mobile carriers, whereon they suffer from weathering and dust impacts. In this study, the erosion of ZnS ceramics was simulated by the abrasive damaging of polished specimens, and the response of the crystal lattice on the external forcing was investigated by the method of photoluminescence (PL). Impacts of isolated hard particles were modelled with the discrete shocks of a pointed striker, and fractoluminescence (FL) from the damaged spot was detected. The FL evidenced that the impact forcing triggers a two-stage mechanism of damage nucleation in this ductile ceramic. The dislocation motion at the stage of initial deformation followed by the interatomic bonds breakage at the stage of cracking. The PL data showed the higher stability of crystallites in chemically vapor-deposited (CVD) ZnS ceramics as compared with the same compounds obtained by the hot pressing (HP) or physical vapor-deposition (PVD) technologies. The abrasive treatment of ZnS-CVD did not affect significantly the entirety of crystallites because of plasticity of intercrystallite substance, in which the impact-induced tension dissipated. Undamaged crystallites retained their optical properties that is did not exhibit additional absorbance. Thus, the decrease of the transmissive capability under particle impacts occurs predominantly due to light scattering on the newly-formed surface irregularities.

Chemically inert 40 keV Ar+ ions were implanted into fused SiO2 with doses in the range of 1×1014 to 1×1016 ion/cm2. The implanted specimens were subjected to the localized impact damaging by a pointed striker. The acoustic emission method was applied to assess the dependence of the microcracking process on the implantation dose. The fractoluminescence method showed the generation of non-bridged oxygen hole centers (NBOHC) [ Si–O–] in newly formed microcracks. The performed experiments revealed a critical fluence, which affected in a non-linear manner the fractoluminescent activity due to changes in the mechanical properties of the Ar+-treated surface layer. An interplay between random and correlated damage accumulation at various structural levels was demonstrated.

Samples of SiC ceramics differing in porosity in the range 1–9% were damaged by a falling weight, and the fractoluminescence (FL) activity lasting up to 0.4 ms was detected with the time resolution of 10 ns. The recorded time series of the light emission were used for constructing the distributions of the energy release in FL pulses and the time intervals between pulses. The energy release in damage events evolved from a self-similar (power law) distribution in low porous ceramics to a fully random (exponential) distribution in more porous samples. The sequence of time intervals between FL pulses exhibited an opposite trend as transforming from the fully random set of “waiting times” in lower porous ceramics into the self-similar time distribution in the most porous ceramics. These changes in the mechanical behavior of tested ceramics were explained by the formation of the oxidized film on the pore surface and by the increasing structural role of bridges between sintered particles in more porous ceramics, which serve as stress concentrators.

The effects of resistive switching were investigated in composite films based on multifunctional nonconjugated polymers such as poly(9-vinylcarbazole)—PVK mixed with particles of graphene (Gr) and graphene oxide (GO). The concentration of Gr and GO particles in the PVK matrix was varied in the range of 1–3 wt%, which is close to the percolation threshold in these systems. It was found that the effect of switching in structures of the form Al/PVK:Gr(GO)/ITO/PET manifests itself in a sharp change of the electrical resistance of the composite film from a low-conducting state to a relatively high-conducting state when applying a bias to Al–ITO electrodes of ∼0.2–0.4 V, which is below the threshold switching voltages for similar composites. The cyclic voltammetric measurements of PVK:Gr(GO) films were carried out. It was found that the potential of redox transition of Gr/GO belongs to the interval of redox-switching voltage of PVK:Gr(GO)/ITO/PET composite films with effect of the resistive switching. The possible mechanism of the resistive switching, which is associated with the redox processes as well as with processes of capture and accumulation of charge carriers by Gr (GO) particles introduced into the matrices of the PVK polymer due to reduction/oxidation processes is discussed.

The optical and electrical properties of films and field-effect transistors (FETs) based on pure MEH-PPV, neat CsPbBr3 nanocrystals (NCs), and MEH-PPV:CsPbBr3 NCs composites with different contents of CsPbBr3 NCs are investigated. The films were characterized by absorbance, atomic-force microscope and current-voltage characteristics (I-Vs) techniques. Relative PL and EL intensities and PL spectra of the pure MEH-PPV, neat CsPbBr3 NCs and MEH-PPV:CsPbBr3 NCs films were measured at 300 K at various levels of optical and electrical excitation power; these dependencies of the PL and EL intensities turned out to be sublinear and superlinear respectively. FETs based on MEH-PPV:CsPbBr3 NCs (1:1) films exhibit I-Vs at 290 – 100 K a dominant hole transport mechanism. The mobility of charge carriers was determined at 290 K for neat CsPbBr3 NCs (for electrons: 2.7 10−2 cm2/Vs) and MEH-PPV:CsPbBr3 NCs (1:1) (for holes: 9 cm2/Vs). The temperature dependence of the hole mobility μFET(T) of FETs based on MEH-PPV:CsPbBr3 NCs (1:1) films characteristic of the hopping mode. It was found that the superlinearity of the dependence of EL of MEH-PPV:CsPbBr3 NCs LE-FETs at 290 K increases with increasing concentration of CsPbBr3 NCs due to efficient energy transfer between CsPbBr3 NCs and the MEH-PPV polymer matrix, and also because of the probability of electron tunneling through the potential barrier to electrode. It is expected that the obtained MEH-PPV:CsPbBr3 NCs nanocomposite films will be useful for efficient applications in nanotechnology LEDs, FETs and LE-FETs.

We report on a solution processed hybrid organic field-effect transistors (OFETs) incorporating both organic semiconductor – poly(9-vinylcarbazole) (PVK) and graphene oxide (GO) flakes. We have found that PVK:GO hybrid OFETs with Au–Al source–drain electrodes exhibit the mobility as high as 3.8–6.7 cm 2 V −1 s −1 under concentration of the GO flakes varies from 3 up to 9.5 wt.% respectively. The on/off ratio of PVK:GO hybrid OFETs is found to be ∼10 2 –10 3 at source–drain and gate operating voltages below ∼5 V. The reversible switching of the source–drain current (from low to high I SD and back) is found at positive and negative V SD ∼ 12–13 V in the PVK:GO OFET structures (GO ∼ 3 wt.%) with Au–Al source–drain electrodes. The possible mechanism of enhancing field-effect mobility in the PVK:GO OFET structures is discussed.

Composite films based on bacterial cellulose (BC) modified with conductive polymer PEDOT/PSS are synthesized. Structural, optical and electrical properties of such composite films are investigated. It was found that the obtained BC:PEDOT/PSS films characterized by strong absorption in the red and near-infrared spectral region and by weak intensity of photoluminescence at 300 K. The temperature dependence of the resistivity of the BC:PEDOT/PSS films follows a power law in the temperature interval 300–80 K and the resistivity values vary weakly with time. The charge carrier transport in the BC:PEDOT/PSS composite films governed mainly by the charge transport in the conducting polymer. The obtained BC:PEDOT/PSS films are promising for application as biocompatible electrodes, temperature sensors and other biochips, which are compatible with technology of printable organic electronics.