Photosensitive hybrid layers are obtained by electrochemical polymerization of pyrrole and 3,4‑ethylenedioxythiophene in the presence of water-soluble sodium salt of zinc octa(3′,5′-dicarboxyphenoxy)phthalocyaninate containing 16 ionogenic carboxylate groups. The process of the hybrid layer electrodeposition was found to occur most effectively in galvanostatic and potentiostatic modes on the sublayer of poly-3,4-ethylenedioxythiophene–polyacid complex. The electronic and chemical structure and morpho-logy of the hybrid layers of polypyrrole obtained in the presence of zinc octa(3′,5′-dicarboxyphenoxy)phthalocyaninate were studied. Possible reasons are considered why the measured values of photosensitivity and external quantum yield of charge-carrier generation in polypyrrole–zinc octa(3′,5′-dicarboxyphenoxy)phthalocyaninate are several times higher than in poly-3,4-ethylenedioxythiophene–zinc octa(3′,5′-dicarboxyphenoxy)phthalocyaninate.

Photoconductivity of a composite of poly-N-vinylcarbazole with carbocyanine dye was studied. The efficiency of photogeneration of charge carriers was measured by the electrographic discharge technique. The photocurrent in composite films increased when a hole transport layer was deposited on electrode and n-type silicon nanoparticles were incorporated into the layer. The Si nanoparticles can serve as additional hole transport pathways and increase the efficiency of the photogeneration of charge carriers in the photoconductor composite.

Basic processes of the electroluminescence phenomenon in OLED structures are described. The conventional theoretical models for injection, transport and recombination of charge carriers and their relationship with the obtained experimental data are discussed. The mobility of charge carriers is a key characteristic of the electron and hole transport. Methods for measuring mobility that adequately reflect the transport of charge carriers in OLEDs are considered.

In this study, we present a complex investigation for miniaturizing of perovskite photodiodes (PPDs) in various geometries with use of ultraviolet laser scribing (UV-LS). Employing a 355 nm (3.5 eV) pulsed laser at 30 kHz, we successfully manufactured PPDs with pixel configurations of 70x130 um2, 520x580 um2, and 2000x2000 um2. The utilization of UV-LS has a proven efficiency in achieving relevant diode characteristics, such as low dark currents and high shunt resistance, as well as ultrafast response. The multi-step scribing cycle provided precise patterning of perovskite photodiodes (PPDs) in a string design. The dark current densities demonstrated exceptional uniformity, ranging from 10-10 A/cm2 for 2000x2000 um2 pixelated PPDs to 10-9 A/cm2 for the 70x130 um2 configuration. The string PPDs, consisting of 10 pixels per string, displayed homogenous dark current values, ensuring effective isolation between devices. Under green light illumination (540 nm), all PPD types exhibited a broad Linear Dynamic Range (LDR). Specifically, LDR values reached 110 dB, 117 dB, and 136 dB for 70x130, 520x580, and 2000x2000 devices, respectively, spanning an illumination intensity range from 2*10-3 mW/cm2 to 2 mW/cm2. High responsivity values up to 0.38 A/W, depending on the PPDs geometry, highlight the potential of laser scribing devices for sensing in the visible range. The calculated specific detectivity performance (from 1011 to 1013 Jones) surpasses commercial analogs, while the sub-microsecond response of 70x130 um2 and 520x580 um2 miniaturized devices underscores their suitability for precise time resolution detection systems.

The electrochemical polymerization of 3,4-ethylenedioxythiophene in the presence of a water-soluble Na+-containing fullerene with hydroxyl groups is studied. The monitoring of the electrosynthesis process by spectroscopic methods shows that during the polymerization of 3,4-ethylenedioxythiophene, fullerenol incorporates into the film composition, regardless of the fullerenol concentration used. The electronic structure, morphology, spectroelectrochemical and electrochemical properties, and near-IR photoconductivity of the poly-3,4-ethylenedioxythiophene–fullerenol composite films are studied for the first time. A mechanism of photoconductivity is proposed, related to the fact that during the photoexcitation of the composite, the electron transfer from the polaron (bipolaron) state of poly-3,4-ethylenedioxythiophene to the LUMO level of fullerenol increases the concentration of photogenerated charge carriers.

The possibility of using push-pull systems based on furazanopyrazine in organic light-emitting diodes (OLEDs) and photovoltaic film devices was shown for the first time. The emission of all the obtained light-emitting diodes had a yellow-green color, and a maximum brightness of 45600 cd m −2 was achieved at a maximum current efficiency of 2.9 cd A −1 . It was determined that the mobility of charge carriers measured in different current modes for these push-pull systems ranged from 10 −4 to 4 · 10 −6 cm 2 V −1 s −1 , considerably exceeding the values of the well-known compound Spiro-MeOTAD, widely used in high-efficiency photovoltaic devices.

We developed a three-terminal ion-sensitive device (TTISD) as a proton (H+) and arsenic (As3+) sensor for the detection of glucose and As(III) dissolved in water. The TTISD was fabricated using the e-beam evaporation and glancing angle deposition (GLAD) technique. The TiO2 nanowires (NWs) were grown by GLAD on the conducting nafion channel of the TTISD to immobilize the test specimens. Arsenic (As) contamination in drinking water is a burning issue as it’s a threat to human health beyond the safe limit of As(III) in drinking water (0.005 mg/dL). Glucose concentration within the limit of 0–200 mg/dL in various body fluids, such as blood, sweat, and saliva is also a necessary parameter to monitor. Early detection of high As(III) concentration in water and regular monitoring of glucose concentration in the human body are essential for human health and safety. This work presents a common nano-hybrid platform for the detection of low-concentration glucose (40–200 mg/dL) and high-concentration arsenic (0.02–2 mg/dL) in drinking water. The device exhibits a rapid response time of ~1 s, enabling real-time detection of glucose and As(III).

A study is performed of the photophysical properties of indolo[3,2-b]carbazole-based compounds synthesized earlier. The charge carrier mobility in the space charge-limited current mode and the energy levels of the highest occupied and lowest unoccupied molecular orbitals in the compounds are determined. It is shown that indolo[3,2-b]carbazole derivatives can be used as hole transporting layers in organic light-emitting diodes.

A series of tricyclic naphthothiophenes - photocyclization products (8-methoxynaphtho[1,2-b]thiophene; 6,7dimethoxynaphtho[1,2-b]thiophene; 8-methoxynaphtho[2,1-b]thiophene) have been studied. HOMO and LUMO levels, as well as a gap between them was accessed by cyclic voltammetry and optical spectroscopy. Double potential step chronoamperometry showed that the former naphthothiophene exhibits slower current decay than the other substances. Charge carrier mobility measured by the CELIV technique was estimated to be of the order of 10-4 cm2V- 1s- 1 for 0.2 mu m films and approaches 10-1 cm2V- 1s- 1. for the 5 mu m film of 8-methoxynaphtho[1,2b]thiophene. It is believed the high mobility is associated with the ordering of the high conductivity axis of the microcrystals in the layers.

To clarify the pathogenesis and molecular basis of ischemia-related nerve cell death, we examined the occurrence of DNA fragmentation as a hallmark of apoptotic cell death following incomplete ischemia in the rat brain by means of in situ end labeling of fragmented DNA, Incomplete ischemia was produced by permanently occluding one carotid artery, while temporarily occluding the other, The condensed nuclei of ischemic neurons in the neocortex, and in the subiculum and CA1 area of the hippocampus were positively stained 24 h and 3 days following vessel occlusion, respectively, and their morphology was typically apoptotic. The ischemic neurons with condensed nuclei gradually increased in number and were clearly stained for fragmented DNA in these areas. The labeled nuclei in the neocortex became pyknotic 72 h later, and in the hippocampus 7 days later incomplete ischemia. After attaining a peak, the number of labeled nuclei decreased with the duration of recovery in all areas. These results suggest that an apoptotic process plays, at least primarily, a role in the degeneration of neurons associated with incomplete forebrain ischemia in rat.

New small molecule D–π–A compounds, bearing thieno[3,2-b]indole and benzo[b]thieno[2,3-d]thiophen-3(2H)-one scaffolds, were prepared, characterized and utilized as electron transport materials in perovskite solar cells.

The photoelectric and optical characteristics of an organic solar cell (OSС) with a hole-transport layer based on a polyaniline complex and a photoactive layer with a bulk heterojunction based on P3HT polythiophene derivative and PC71BM fullerene have been studied. The results of modeling the optical properties of the functional layers and experimental measurements of the OSC characteristics enabled the optimal values of the thickness of the functional layers resulting in the maximum power conversion efficiency of the device to be identified. It has been determined that the hole-transport layer with a thickness of 30–60 nm, while having a transmission of more than 80%, effectively transferred holes to the photoanode from the photoactive layer, in which the exciton generation rate was 5.6–5.9 × 1016 cm–2 s–1. These values of the exciton generation rate at the maximum total light absorption in the device were provided by a photoactive layer with a thickness of 90–100 nm.

This work is devoted to the determination of the mechanisms of generation, transfer, and recombination of charge carriers in a hybrid organic–inorganic system—a polymer poly-3-hexylthiophene with silicon nanoparticles ( nc -Si). It is shown that by varying the nc -Si concentration, it is possible to change the conductivity and photoconductivity of such a system within a fairly wide range, achieving optimal values for applications in optoelectronics (photodetectors, solar cells, etc.). A model is proposed making it possible to describe the photoelectric properties of poly-3-hexylthiophene modified with nc -Si from a single point of view. The model assumes a Gaussian distribution of the density of electronic states along which the hopping transport of charge carriers occurs. The influence of nc -Si mainly affects the parameters of the Gaussian distribution of the density of electronic states and the position of the Fermi level.

5,11-Dihydroindolo[3,2-b]carbazoles were for the first time modified with acceptor 1,2,4,5-tetrazine fragments. The photophysical and charge-transport properties of the synthesized donor-acceptor heterocyclic systems were studied. It was shown that the introduction of the 1,2,4,5-tetrazine moieties makes it possible to increase the hole and electron mobility by one and two orders of magnitude, respectively, as compared to analogous 5,11-dihydroindolo-[3,2-b]carbazole derivatives studied previously.

In this work we demonstrate the beneficial role of MXene doping for both perovskite absorber and electron transporting layer in NiO-based inverted perovskite solar cells. The addition of MXenes permits on one side to easy tune the energy level alignment at perovskite/charge transporting layer interfaces, and on the other side to passivate traps states within the cell structure, which in turn improves charge extraction and collection at the electrodes. The MXene-based engineered cells showed superior performance, with power conversion efficiency exceeding 19% and improved stabilized power output with respect to reference devices. Due to the possibility to finely tune the MXene work function during their chemical synthesis and to their capability in modifying the optoelectronic properties of PSC layers when used as dopant, the proposed approach opens countless ways for engineering inverted PSC structure, strongly promising in term of long-term stability and future scalability on large area devices.

The effect of annealing of organometallic perovskite CH3NH3PbI3 film on its electrical, photoelectric, and optical properties is studied. It was shown that annealing at Та>140 °C leads to the two-phase structure formation consisting of perovskite and lead iodide, the relative content of which depends on the annealing conditions, in particular, on its temperature. The PbI2 formation in the perovskite structure leads to a decrease in the conductivity and photoconductivity of the material. Our studies indicate the possibility of forming planar structures consisting of semiconductor materials with various values of the band gap: 1.6 eV (CH3NH3PbI3) and 2.4 eV (PbI2).

The effect of annealing of a CH3NH3PbI3 organometallic perovskite film on its electrical, photoelectrical, and optical properties is studied. It is shown that annealing at the temperature Ta > 140°C results in the formation of a two-phase structure consisting of perovskite and lead iodide, whose relative content depends on the conditions of annealing, specifically, on the annealing temperature. The formation of PbI2 in the perovskite structure yields a decrease in the conductivity and photoconductivity of the material. The studies suggest the possibility of the formation of planar structures composed of semiconductor materials with different band gaps, 1.6 eV (CH3NH3PbI3) and 2.4 eV (PbI2).