Effect of interface in bilayer polydiphenylenephthalide film on electron transport

The results of studies of multilayer film structures based on a wide-gap polymer using the time of flight technique are shown. Experimental data showed that transport of charge carriers depends strongly on the presence of a polymer/polymer interface. The possibility is shown of increasing the threshold thickness of the experimental structure, in which effects of switching to a highly conducting state induced by uniaxial mechanical pressure are also found. Preliminary interpretation of the obtained data is performed.     

Effect of excessive pressure on the drift mobility of charge carriers in poly(diphenylene phthalide) films

The electron-hole transport in poly(diphenylene phthalide) films has been investigated. The dependence of the drift mobility of charge carriers on the excessive mechanical pressure has been studied using the time-of-flight method. It has been revealed that, with an increase in the thickness of the polymer film, the dispersive transport of charge carries gives way to the quasi-dispersive transport. In thin films in the prethreshold range (i.e., before switching of the samples to the highly conductive state under excessive pressure), the electron mobility increases and exceeds the hole mobility. The experimental results have been discussed in the framework of the model describing the transport through the channels formed by metastable electron-hole pairs.     

Electrodeposited polyaniline/Cu2ZnSnSe4 heterojunction

Journal of Solid State Electrochemistry - One-step method for the electrodeposition of thin Cu2ZnSnSe4 (CZTSe) film onto a polyaniline/FTO/glass substrate was developed. Polyaniline film was...     

Ionic polymerization in an electric field and consequences of the spatial redistribution of growing macroions and counterions

Reaction mixtures in which polymerization processes proceed are investigated both in an electric field and under classical conditions. The observed kinetic effects are explained using a model concept of the primary contribution to the revealed field effects from the dissociation of ion pairs due to the spatial redistribution of ions. This model may be applied to both cationic and anionic polymerization processes.     

Molecular dynamics study of perovskite structures with modified interatomic interaction potentials

The structure of compounds with the perovskite structure ABX₃ (A and B are cations, X are anions O^2—, F^—, Cl^—, Br^—, and I^—), which are widely used in engineering due to unique electrical, optical, and photovoltaic properties, has been considered. Hybrid organic—inorganic halide perovskites important for photovoltaics of a new generation are worth mentioning; they contain cations of organic nitrogen bases as monovalent cations. A molecular dynamics (MD) study of the CaTiO₃ base structure (Ca²⁺, Ti⁴⁺, and O^2—) has been performed in order to develop the methodology of computer simulation and optimization of the shape and parameters of atomic potentials for perovskite systems.     

New Unsymmetrically Substituted Benzothiadiazole-Based Luminophores: Synthesis,Optical, Electrochemical Studies,Charge Transport,and Electroluminescent Characteristics

Three new benzothiadiazole (BTD)-containing luminophores with different configurations of aryl linkers have been prepared via Pd-catalyzed cross-coupling Suzuki and Buchwald–Hartwig reactions. Photophysical and electroluminescent properties of the compounds were investigated to estimate their potential for optoelectronic applications. All synthesized structures have sufficiently high quantum yields in film. The BTD with aryl bridged carbazole unit demonstrated the highest electrons and holes mobility in a series. OLED with light-emitting layer (EML) based on this compound exhibited the highest brightness, as well as current and luminous efficiency. The synthesized compounds are not only luminophores with a high photoluminescence quantum yield, but also active transport centers for charge carriers in EML of OLED devices.     

The influence of light on the conduction switching effect in thin polymer films

The effect of exposure to visible light on pressure- and field-induced switching from the low-conductivity to the high-conductivity state in thin polymer films was experimentally studied. The switching effect was observed in poly(diphenylene phthalide) and polyvinylcarbazole layers doped with a cyanine dye. Doping with the dye reduces the voltage at which the polymer is switched to the conducting state. However, an Al—dye complex is formed with time, which results in an increase in the switching voltage and pressure. It was found that illumination leads to the appearance of additional conductivity in the sample; in the samples prone to switching to the conducting state, light stimulates switching and leads to blocking the injection sites for charge carriers in the low-conductivity state.     

The specific effect of graphene additives in polyaniline-based nanocomposite layers on performance characteristics of electroluminescent and photovoltaic devices

A comparative study of the effect of graphene admixture to polyaniline hole-injection layers of polymer light emitting diodes (PLEDs) and anode buffer layers of organic solar cells (OSCs) has been performed. The layers have been made from the complex of polyaniline with poly-2-acrylamido-2-methyl-1propanesulfonic acid with (or without) addition of 1 wt % graphene prepared by the mechanochemical method. It has been shown that the effects of the graphene addition into the auxiliary PLED and OSC layers are opposite: performance characteristics (current and light efficiency) of the former deteriorate and those of the latter are improved (in particular, the powerconversion efficiency increases by a factor of 1.4). The reasons considered to be behind the opposite effects are a significant difference in the currents flowing through the PLED and OSC, a more developed interface between the OSC anode buffer layer and photolayer, and channeling the longitudinal conductivity at the interface between graphene nanoparticles and polyaniline.     

Bimolecular recombination of charge carriers in pure and molecularly doped branched polyphenylenevinylenes

General problems of bimolecular recombination of charge carriers in both pure and molecularly doped branched polyphenylenevinylenes are addressed. Experiments are performed via the nonstationary radiation-induced conductivity method. Transient-current curves are numerically calculated in terms of the multiple-trapping model. Good agreement between the calculated and experimental curves is attained. In the investigated polymers, the Langevin mechanism of bimolecular recombination is active.     

Polymeric Semiconductors with a Pre‐Specified Alternation of Conjugated Bonds and Metal Clusters

Summary: In this work the first samples of polymeric semiconductors of a new structure are produced. Their electric conductivity is of the order ∼10⁻² Ohm⁻¹ · cm⁻¹ and it increases with temperature. Their synthesis includes a stage of radiation grafting of a matrix‐type on stretched polyamide films. Conducting molecular circuits in such materials include fragments with conjugated bonds and metal clusters. The alternation of these fragments is determined by the polyamide matrix.

Plot of voltage versus current determined for new polymer semiconducting films where fragments with conjugated bonds alternate with silver clusters.