Investigation of Photoelectric Converters with a Base Cadmium Telluride Layer with a Decrease in Its Thickness for Tandem and Two-sided Sensitive Instrument Structures

Photovoltaic cells with a base layer of cadmium telluride with a decrease in its thickness are studied. It is known that the widespread use of photovoltaic converters is constrained by their high price in the case of highly efficient instrument structures, or low efficiency. The creation of tandem and two-sided sensitive photoelectric converters will reduce their cost while increasing their efficiency. However, to create tandem and two-sided sensitive photoelectric converters, the necessary conditions are the use of transparent contacts and a decrease in the thickness of the base layer for efficient absorption of incident radiation by the converter, which is lower. In the research process, it was found that reducing the thickness of the base layer to 1 μm allows to increase the efficiency of the photoelectric transducer during irradiation from the back. An increase in the efficiency of the photoelectric converter occurs due to a decrease in the distance from the generation region of nonequilibrium charge carriers in the region of separation. If the thickness of the base layer is less than 1 μm, then regardless of which side of the irradiation is carried out, a decrease in the efficiency of the instrument structure is observed. Increase in the efficiency of photoconverters is associated with an increase in the negative influence of recombination processes on the back contact, a decrease in the number of charge carriers generated due to incomplete absorption of incident radiation, and a decrease in the volume of the built-in field of the separating barrier when it overlaps with the depletion region of the back contact. ITO/CdS/CdTe/Cu/ITO SCs with a base layer thickness of 1 μm demonstrates degradation stability. The highest value of efficiency in the case of illumination from the front side 8.1 % and with illumination from the back side 3.8 % received after a year of operation of the photovoltaic converter

Opportunities and threats of WTO membership of Ukraine in foreign trade of high-technology products under conditions of co-operation with EU countries and Customs Union of Belarus, Kazakhstan, and Russia

The article considers the problem of consequences of membership in the World Trade Organisation (WTO) for Ukraine in foreign trade of high-technology products under conditions of co-operation with EU countries and the Customs Union of Belarus, Kazakhstan and Russia (CU). The article shows that after Ukraine joined WTO there were some rather significant reductions of tariff rates for Ukrainian products and liberalisation of access to the world markets, at the same time the internal Ukrainian market became more open for imported products. The article studies specific features and changes in the high-technology products market after Ukraine joined WTO. It analyses dynamics of volumes and specific weight of the world export-import of high-technology products and the structure of the world export and import of high technology products, including by individual countries and groups. The article makes a conclusion about a weak high-technology component of the Ukrainian export. It studies the structure of export of high-technology products of EU, CU and Ukraine. It shows that in order to develop the high-technology products market Ukraine needs to develop foreign trade with EU countries and also to continue co-operation with CU countries, in particular, with Russia. The article shows that the aerospace industry products takes the biggest specific weight in the export of high-technology products of Ukraine. It considers prospects of development of civil aircraft production in the world and Ukraine under the modern conditions. It analyses strengths and weaknesses of the aircraft construction industry and also threats and opportunities for aircraft construction of Ukraine due to external environment influence. The article shows that Ukraine cannot keep national aircraft building on its own, that is why it is necessary to develop close co-operation both with Russian enterprises and with the countries of the Western Europe. It offers recommendations on preservation of production potential of the aircraft construction industry of Ukraine. The final conclusion of the study is the following: despite the world financial and economic crisis, diversification and change of the Ukrainian export structure is going on since Ukraine joined WTO, which not only facilitates reduction of dependence of the national economy on individual geographical markets, but also predetermines the necessity to protect interests of the national producers by the Ukrainian government in new markets

Development of A Method for Obtaining A CdS/CdTe/Cu/Au Module on A Flexible Substrate Designed for Backup Supplying Systems Prevention of Emergency Situations

The study of methods for obtaining base layers of cadmium telluride for the creation of efficient solar cells on a flexible substrate, intended for backup power supply of security systems and facility control. Considering that the polyamide film is stable up to a temperature of 450 °С, the formation of the base layers of solar cells based on cadmium telluride on flexible polyamide substrates was carried out by the method of DC magnetron sputtering. Using the chosen method, experimental samples of micromodules on a flexible substrate with series-connected solar cells based on CdS/CdTe/Cu/Au were obtained. To understand the effect of the failure of one or more solar cells on the efficiency of the entire micromodule during operation, an analysis of the initial parameters and light diode characteristics of individual solar cells of micromodules was carried out. The design of the micromodules, in which the solar cells were connected in series, made it possible to separately measure their output parameters. It was found that the creation of a Cu/Au rear tunnel contact made it possible to obtain high values of the output parameters for individual solar cells, but the micromodule contains a limitation by a shunted solar cell. However, the greatest role in reducing the efficiency of the entire micromodule is played by ineffective absorption of radiation when passing through the polyamide film, which led to a decrease in the efficiency of the entire micromodule, in which there is a shunted element, to 3.9 %. The maximum efficiency of the obtained samples of micromodules was 5.3