Кафедра "Природничі науки"
Постійне посилання колекціїhttps://repository.kpi.kharkov.ua/handle/KhPI-Press/1703
Увага! Поповнення колекції кафедри "Природничі науки" від травня 2023 року тимчасово призупинено.
Офіційний сайт кафедри http://web.kpi.kharkov.ua/ken
Кафедра "Природничі науки" заснована в 1973 році.
Кафедра забезпечувала викладання дисциплін природничого циклу іноземним громадянам, які готуються продовжувати навчання у вищих навчальних закладах України.
Студенти отримують необхідний рівень знань з природничих дисциплін і мають можливість вступати в будь-які вузи України для подальшого навчання.
Кафедра входить до складу Навчально-наукового інституту міжнародної освіти Національного технічного університету "Харківський політехнічний інститут".
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Документ Operating temperature effect on the thin film solar cell efficiency(Сумський державний університет, 2019) Zaitsev, R. V.; Kirichenko, M. V.; Khrypunov, G. S.; Radoguz, S. A.; Khrypunov, M. G.; Prokopenko, D. S.; Zaitseva, L. V.The made research results of the dependence of the film photovoltaic converter efficiency on their operating temperature and their comparison are considered in the paper. The physical mechanisms of temperature influence analysis on output, diode and electronic parameters of photovoltaic converters were conducted. The output parameters determination of the flexible photovoltaic converters was carried out by measurement of light current-voltage characteristics by using illuminator based on powerful semiconductor LEDs with different colors for simulated radiation which is close to the standard ground and ultraviolet solar spectrum. For ensuring effective non-destructive switching of the test specimens of the flexible PVC based on cadmium telluride to the measurement circle, the special contact device was developed and used. The main feature of contact device is four separate vertically moving metal probes in form of semi spheres with polished surfaces, which makes it impossible to puncture the PVC electrodes. These probes have possibility of individual positioning of each probe that is carried out with the help of a hard rotary console of variable length attached to the body and can be pressed with a given effort without impact on the frontal and any rear electrodes of the PVC experiments. The efficiency temperature coefficients of the photovoltaic converter, which make up for devices with a CdTe of 0.14 %/C, CuInSe2 – 0.36 %/C, amorphous silicon - 0.21 %/C were obtained. The analytical processing and analysis of the light diode characteristic effect on the PVC efficiency based on the CdTe showed that the temperature stability of their efficiency is ensured by the diode current density, the incision of which increases by 50 % from 1.9·10 – 9 A to 2.7·10 – 9 A with the temperature rise from 20 °С to 50 °С. At the same time, it has been established for PVC on the CuInSe and amorphous silicon base that the decrease of short circuit current density, open circuit voltage and fill factor of current-voltage characteristics plays the main role in efficiency reduction with rising temperature.Документ Physical and technological foundations of the "Chloride" treatment of cadmium telluride layers for thin-film photoelectric converters(Сумський державний університет, 2018) Kudii, D. A.; Khrypunov, M. G.; Zaitsev, R. V.; Khrypunova, A. L.The process of deposition of cadmium chloride films during the "chloride" treatment of cadmium telluride base layers for thin-film photoelectric converters (PEC) was studied. It is established that to ensure the reproducibility of the thickness and phase composition of cadmium chloride films, it is necessary to take into account the high hygroscopicity of this material. It is shown that the optimal growth rate of cadmium chloride films is 0.1 μm perminute. At high growth rates, cadmium chloride particulates are deposited on the surface of the CdTe layer base, which causes shunting of the PEC during the "chloride" treat-ment. It is determined that after the "chloride" treatment of CdTe layers, a coarse-grained structure is observed, which is predominantly oriented in the thermodynamic equilibrium direction. In this case, the average grain size increases to 5 μm. It is shown that when performing a "chloride" treatment, the optimum purity of cadmium chloride layers is 98 %, which is due to the doping of CdTe with copper atoms. The disadvantage of copper with the use of more pure cadmium chloride reduces the efficiency of the PEC due to the increase in the series resistivity and the decrease in the photocurrent density. It has been experimentally determined that the optimum thickness of cadmium chloride during the "chloride" treatment and the efficiency of the PEC obtained at the same time depends on the substrate used. Thus, for the ITO/CdS/CdTe/Cu/Au PEC, the optimum thickness of cadmium chloride is 0.40 μm, the efficiency is 9.6 %, and for the NaCl/ITO/CdS/CdTe/Cu/Au PEC – 0.10 μm and 6.4 %, respectively.Документ Amplitude-time characteristics of switching in thin films of cadmium telluride(Сумський державний університет, 2018) Khrypunov, M. G.; Zaitsev, R. V.; Kudii, D. A.; Khrypunova, A. L.The amplitudetime characteristics of switching in thin films of cadmium telluride were investigated when single impulses of 1 μs duration are applied. It has been experimentally established that with an increase in the thickness of the cadmium telluride layer from 3 μm to 8 μm, an increase in the operating threshold from 70 V to 105 V is observed. The maximum residual sample voltage varies from 12 V to 40 V, the minimum – from 5 V to 20 V. The switching time of the samples was no more than 2 nanoseconds; the interelectrode capacity of the samples was no more than 2 pF. All the test samples were operated without failure 20 times. The structural studies of cadmium telluride films by the method of X-ray diffractometry and scanning electron microscopy have made it possible to propose a mechanism for realizing the monostable switching of the columnar structure of cadmium telluride films oriented in the form of melted high-conductivity channels in grains oriented in the direction.