Electrical behaviour, characteristics and properties of anodic aluminium oxide films coloured by nickel electrodeposition

Porous anodic films on 1050 aluminium substrate were coloured by AC electrodeposition of nickel. Several experiments were performed at different deposition voltages and nickel concentrations in the electrolyte in order to correlate the applied electrical power to the electrical behaviour, as well as the characteristics and properties of the coatings. The content of nickel inside the coatings reached 1.67 g/m2, depending on the experimental conditions. According to the applied AC voltage in comparison with the threshold voltage Ut, the coating either acted only as a capacitor when U\Ut and, when U[Ut, the behaviour during the anodic and cathodic parts of the power sine wave was different. In particular, due to the semi-conducting characteristics of the barrier layer, additional oxidation of the aluminium substrate occurred during the anodic part of the electrical signal, whilst metal deposition (and solvent reduction) occurred during the cathodic part; these mechanisms correspond to the blocked and pass directions of the barrier layer/electrolyte junction, respectively

RESEARCH OF THE MAIN COMPONENTS OF INNOVATIVE CAPACITY OF THE INDUSTRIAL ENTERPRISE

The available methodological base of research of innovative capacity of the industrial enterprise is developed, methods definitions and measurements of innovative potential are given. It allowed to offer approach to adoption of administrative decisions in the field of a choice of a certain type of innovations depending on the level of innovative capacity of the enterprise

RESEARCH OF THE MAIN COMPONENTS OF INNOVATIVE CAPACITY OF THE INDUSTRIAL ENTERPRISE

The available methodological base of research of innovative capacity of the industrial enterprise is developed, methods definitions and measurements of innovative potential are given. It allowed to offer approach to adoption of administrative decisions in the field of a choice of a certain type of innovations depending on the level of innovative capacity of the enterprise

Study of Lead-Free Perovskite Solar Cells at Elevated Temperatures and UV Irradiatio

In the present work, the change of the electrical performance is investigated for two lead-free perovskite materials with novel iodide- based and bromide-based compositions under different exploitation conditions, such as light-induced stress, elevated temperatures and ultraviolet light exposure. The charge transport properties are studied in more detail by spectroscopic methods for the cell with the iodide layer due to its greater stability, aiming to understand the degradation mechanism. The results show that this perovskite exhibited excellent stability at UV exposure and acceptable stability at continuous illumination at 600 nm. The device is stable up to 55 °C, when the photovoltage drops. Beyond this threshold temperature, a phase change transition occurs related to traps formation and charge carriers escaping, which affects the photovoltage and it slightly increases

Role of electrode temperature in anodic growth of sulfuric acid alumina films

Studies of the self-organized growth of nanoporous anodic aluminum oxide (AAO) films and anodization parameters have been the subject of decades of research and various theories. At the same time, temperature, being one of the most important parameters in anodizing treatments of aluminum, has been investigated only as a function of electrolyte temperature. This paper presents the results of studying the growth kinetics and morphology of AAO formed by anodization processes in 1 M H2SO4 at different anode temperatures. The activation energy of ionic conductivity for AAO determined in this study was 0.41 eV for sulfuric acid, which was greater than the activation energy of 0.34 eV for oxalic acid. The effect of anode temperature on the pore diameter (dpore) and the interpore distance (Dinter) was studied. It was demonstrated that in the temperature range from 10 to 40 °C, the dpore and Dinter did not change with the anode temperature, with values equal to 12.5 ± 0.1 nm and 52.5 ± 0.2 nm, respectively. However, when the anode (aluminum) temperature was increased to 60 °C, the dpore increased to 16 nm. The results obtained show that by increasing the temperature of the anode from 20 to 40 °C, it is possible to increase the ionic conductivity of AAO and thus achieve a greater than threefold increase in the the rate of AAO growth, without altering the porous morphology of the anodic films

Effect of anodizing regimes on the volume expansion factor of the oxide films

The volume expansion factor of porous alumina, formed by through anodizing of an Al foil in ox- alic and sulphuric acid has been studied. The thickness of obtained porous alumina films was measured by a mechanical profilometer with a computer signal processing. The volume expansion factor of porous alumina varied from 1.35 to 1.65. Linear dependences were obtained for the vol- ume expansion factor of porous alumina versus the anodizing voltage and the ionic current density logarithm versus the inverse volume expansion factor. Unlike oxide formation in sulphuric acid, these dependences have two subsequential rectilinear regions in oxalic acid

Features of the porous morphology of anodic alumina films at the initial stage of disordered growth

A characteristic feature of disordered porous anodic film growth at the initial stage of aluminum anodizing was revealed by varying the electrolyte type and anodizing voltage. The samples were obtained by the electrochemical oxidation of thin aluminum films (100 nm thick) on SiO2/Si substrates in a 0.3 M oxalic acid at 10–50 V and were studied by SEM. The ImageJ analysis of the images revealed the simultaneous development of two large groups of pores: major pores with a large diameter and minor pores with a smaller diameter. When anodizing in oxalic acid at 10–50 V, it has been shown that the ratio of the diameters of the major and minor pores remains constant and is about 1.17. Using a geometric model, we demonstrated that the centers of the minor pores are located inside the elementary hexagonal cell formed by the centers of the major pores. Moreover, our results are very close to the theoretical value of 2/√3. At the initial stage of disordered pore growth, the development of minor pores rather than major pores is not a random process and is determined by energy-efficient conditions for the development of pores inside the hexagonal cells formed by the major pores. The increase in compressive mechanical stress in the anodic film leads to an interruption in the development of such pores

Synthesis and electrophysical properties of the catodic layer of anodic titanium oxide for perovskite solar cells

В статье рассмотрены синтез и электрофизические свойства катодного слоя анодного оксида титана для перовскитных солнечных элементов

Applying Aniline for P-doping of PEDOT:PSS Films to Improve Their Conductivity and Efficiency of Perovskite Solar Cells

Poly(3,4- ethylenedioxythiophene):polystyrene sulfonate (PEDOT: PSS) is responsible for hole extraction efficiency and hole transport in the perovskite solar cell structure. The inclusion of PSS reduces the conductivity of the PEDOT films, which inhibits hole transport and results in a low photo current of the perovskite solar cell. In this work, an aniline solution was used as an additive in the PEDOT: PSS thin film to increase electrical conductivity. Two different methods were used to incorporate the additive: surface and volume treatment. The results show that the surface treatment with aniline solution can significantly increase the conductivity of PEDOT: PSS film. Moreover, the photoconversion efficiency of the perovskite solar cell with such a PEDOT: PSS layer is increased 1.5 times compared to the untreated one

Recognitionand Analysis of Microstructure Parameters of Porous Anodic Films Using ImageJ

The most important parameters that characterize the microstructure of the films and determine the possibility of their use as porous templates are the pore diameter, porosity, and ordering of the porous structure. Therefore, to increase the efficiency of the use of porous anodic alumina films, it is important to investigate the effect of the formation modes on the microstructure. The aim of this work was to choose and optimize a model for processing experimental data obtained by scanning electron microscopy in the ImageJ to determine the parameters of the microstructure of porous films. The work shows the result of SEMimage analysis and obtains plots of pore diameter distribution by size and determines the diameter of the main pores