This study explored the performances of CZTS-based thin-film solar cell with three novel buffer layer materials ZnS, CdS, and CdZnS, as well as with variation in thickness of buffer and absorber-layer, doping concentr...This study explored the performances of CZTS-based thin-film solar cell with three novel buffer layer materials ZnS, CdS, and CdZnS, as well as with variation in thickness of buffer and absorber-layer, doping concentrations of absorber-layer material and operating temperature. Our aims focused to identify the most optimal thin-film solar cell structure that offers high efficiency and lower toxicity which are desirable for sustainable and eco-friendly energy sources globally. SCAPS-1D, widely used software for modeling and simulating solar cells, has been used and solar cell fundamental performance parameters such as open-circuited voltage (), short-circuited current density (), fill-factor() and efficiency() have been optimized in this study. Based on our simulation results, it was found that CZTS solar cell with Cd<sub>0.4</sub>Zn<sub>0.6</sub>S as buffer-layer offers the most optimal combination of high efficiency and lower toxicity in comparison to other structure investigated in our study. Although the efficiency of Cd<sub>0.4</sub>Zn<sub>0.6</sub>S, ZnS and CdS are comparable, Cd<sub>0.4</sub>Zn<sub>0.6</sub>S is preferable to use as buffer-layer for its non-toxic property. In addition, evaluation of performance as a function of buffer-layer thickness for Cd<sub>0.4</sub>Zn<sub>0.6</sub>S, ZnS and CdS showed that optimum buffer-layer thickness for Cd<sub>0.4</sub>Zn<sub>0.6</sub>S was in the range from 50 to 150nm while ZnS offered only 50 – 75 nm. Furthermore, the temperature dependence performance parameters evaluation revealed that it is better to operate solar cell at temperature 290K for stable operation with optimum performances. This study would provide valuable insights into design and optimization of nanotechnology-based solar energy technology for minimizing global energy crisis and developing eco-friendly energy sources sustainable and simultaneously.展开更多
In this study we are reporting annealing induced optical properties of bismuth ferrite (BiFeO3) thin films deposited on glass substrate via spin coating at 5000 rpm. The structural, optical and surface morphology of B...In this study we are reporting annealing induced optical properties of bismuth ferrite (BiFeO3) thin films deposited on glass substrate via spin coating at 5000 rpm. The structural, optical and surface morphology of BiFeO3 (BFO) thin films have been studied via X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Optical absorption (UV-Vis) and Photoluminescence (PL) spectroscopy. XRD spectra confirm annealing induced phase formation of BiFeO3 possessing a rhombohedral R3c structure. The films are dense and without cracks, although the presence of porosity in BFO/glass was observed. Moreover, optical absorption spectra indicate annealing induced effect on the energy band structure in comparison to pristine BiFeO3. It is observed that annealing effect shows an intense shift in the UV-Vis spectra as diffuse absorption together with the variation in the optical band gap. The evaluated optical band gap values are approximately equal to the bulk band gap value of BiFeO3.展开更多
Sentiment analysis is a method to identify and understand the emotion in the text through NLP and text analysis. In the era of information technology, there is often a certain error between the comments on the movie w...Sentiment analysis is a method to identify and understand the emotion in the text through NLP and text analysis. In the era of information technology, there is often a certain error between the comments on the movie website and the actual score of the movie, and sentiment analysis technology provides a new way to solve this problem. In this paper, Python is used to obtain the movie review data from the Douban platform, and the model is constructed and trained by using naive Bayes and Bi-LSTM. According to the index, a better Bi-LSTM model is selected to classify the emotion of users’ movie reviews, and the classification results are scored according to the classification results, and compared with the real ratings on the website. According to the error of the final comparison results, the feasibility of this technology in the scoring direction of film reviews is being verified. By applying this technology, the phenomenon of film rating distortion in the information age can be prevented and the rights and interests of film and television works can be safeguarded.展开更多
The results of an experimental study of long-term relaxation of the photoelectret state of polycrystalline CdTe:(Ag, Cu, Cd) and Sb<sub>2</sub>Se<sub>3</sub>:Se films with an anomalous photovol...The results of an experimental study of long-term relaxation of the photoelectret state of polycrystalline CdTe:(Ag, Cu, Cd) and Sb<sub>2</sub>Se<sub>3</sub>:Se films with an anomalous photovoltaic property are presented. In such films, the residual photovoltage is caused by the separation of photocarriers by the built-in electrostatic field of the near-surface region of space charges and their asymmetric capture by deep levels of impurities or complexes, including impurity atoms and intrinsic defects, both in the bulk and on the surface of crystal grains. It has been shown that in activated films, a two-step exponential temporary relaxation of the initial photovoltage of the order of V<sub>APV</sub> ≈ (500-600) V is detected, and only 10% of it experiences long-term relaxation (t ≈ 100-120 min).展开更多
We report the performances of a chalcopyrite Cu(In, Ga)Se<sub>2 </sub>CIGS-based thin-film solar cell with a newly employed high conductive n-Si layer. The data analysis was performed with the help of the ...We report the performances of a chalcopyrite Cu(In, Ga)Se<sub>2 </sub>CIGS-based thin-film solar cell with a newly employed high conductive n-Si layer. The data analysis was performed with the help of the 1D-Solar Cell Capacitance Simulator (1D-SCAPS) software program. The new device structure is based on the CIGS layer as the absorber layer, n-Si as the high conductive layer, i-In<sub>2</sub>S<sub>3</sub>, and i-ZnO as the buffer and window layers, respectively. The optimum CIGS bandgap was determined first and used to simulate and analyze the cell performance throughout the experiment. This analysis revealed that the absorber layer’s optimum bandgap value has to be 1.4 eV to achieve maximum efficiency of 22.57%. Subsequently, output solar cell parameters were analyzed as a function of CIGS layer thickness, defect density, and the operating temperature with an optimized n-Si layer. The newly modeled device has a p-CIGS/n-Si/In<sub>2</sub>S<sub>3</sub>/Al-ZnO structure. The main objective was to improve the overall cell performance while optimizing the thickness of absorber layers, defect density, bandgap, and operating temperature with the newly employed optimized n-Si layer. The increase of absorber layer thickness from 0.2 - 2 µm showed an upward trend in the cell’s performance, while the increase of defect density and operating temperature showed a downward trend in solar cell performance. This study illustrates that the proposed cell structure shows higher cell performances and can be fabricated on the lab-scale and industrial levels.展开更多
AlN was used as a host material and doped with Eu grown on Si substrate by pulsed laser deposition (PLD) with low substrate temperature. The X-ray diffraction (XRD) data revealed the orientation and the composition of...AlN was used as a host material and doped with Eu grown on Si substrate by pulsed laser deposition (PLD) with low substrate temperature. The X-ray diffraction (XRD) data revealed the orientation and the composition of the thin film. The surface morphology was studied by scanning electron microscope (SEM). While raising the annealing temperatures from 300˚C to 900˚C, the emission was observed from AlN: Eu under excitation of 260 nm excitation. The photoluminescence (PL) was integrated over the visible light wavelength shifted from the blue to the red zone in the CIE 1931 chromaticity coordinates. The luminescence color coordination of AlN: Eu depending on the annealing temperatures guides the further study of Eu-doped nitrides manufacturing on white light emitting diode (LED) and full color LED devices.展开更多
A boron-silicon film was formed from boron trichloride gas and dichlorosilane gas at about 900℃in ambient hydrogen at atmospheric pressure utilizing a slim vertical cold wall chemical vapor deposition reacto...A boron-silicon film was formed from boron trichloride gas and dichlorosilane gas at about 900℃in ambient hydrogen at atmospheric pressure utilizing a slim vertical cold wall chemical vapor deposition reactor designed for the Minimal Fab system. The gas flow rates were 80, 20 and 0.1 - 20 sccm for the hydrogen, dichlorosilane and boron trichloride gases, respectively. The gas transport condition in the reactor was shown to quickly become stable when evaluated by quartz crystal microbalances at the inlet and outlet. The boron-silicon thin film was formed by achieving the various boron concentrations of 0.16% - 80%, the depth profile of which was flat. By observing the cross-sectional TEM image, the obtained film was dense. The boron trichloride gas is expected to be useful for the quick fabrication of various materials containing boron at significantly low and high concentrations.展开更多
文摘This study explored the performances of CZTS-based thin-film solar cell with three novel buffer layer materials ZnS, CdS, and CdZnS, as well as with variation in thickness of buffer and absorber-layer, doping concentrations of absorber-layer material and operating temperature. Our aims focused to identify the most optimal thin-film solar cell structure that offers high efficiency and lower toxicity which are desirable for sustainable and eco-friendly energy sources globally. SCAPS-1D, widely used software for modeling and simulating solar cells, has been used and solar cell fundamental performance parameters such as open-circuited voltage (), short-circuited current density (), fill-factor() and efficiency() have been optimized in this study. Based on our simulation results, it was found that CZTS solar cell with Cd<sub>0.4</sub>Zn<sub>0.6</sub>S as buffer-layer offers the most optimal combination of high efficiency and lower toxicity in comparison to other structure investigated in our study. Although the efficiency of Cd<sub>0.4</sub>Zn<sub>0.6</sub>S, ZnS and CdS are comparable, Cd<sub>0.4</sub>Zn<sub>0.6</sub>S is preferable to use as buffer-layer for its non-toxic property. In addition, evaluation of performance as a function of buffer-layer thickness for Cd<sub>0.4</sub>Zn<sub>0.6</sub>S, ZnS and CdS showed that optimum buffer-layer thickness for Cd<sub>0.4</sub>Zn<sub>0.6</sub>S was in the range from 50 to 150nm while ZnS offered only 50 – 75 nm. Furthermore, the temperature dependence performance parameters evaluation revealed that it is better to operate solar cell at temperature 290K for stable operation with optimum performances. This study would provide valuable insights into design and optimization of nanotechnology-based solar energy technology for minimizing global energy crisis and developing eco-friendly energy sources sustainable and simultaneously.
文摘In this study we are reporting annealing induced optical properties of bismuth ferrite (BiFeO3) thin films deposited on glass substrate via spin coating at 5000 rpm. The structural, optical and surface morphology of BiFeO3 (BFO) thin films have been studied via X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Optical absorption (UV-Vis) and Photoluminescence (PL) spectroscopy. XRD spectra confirm annealing induced phase formation of BiFeO3 possessing a rhombohedral R3c structure. The films are dense and without cracks, although the presence of porosity in BFO/glass was observed. Moreover, optical absorption spectra indicate annealing induced effect on the energy band structure in comparison to pristine BiFeO3. It is observed that annealing effect shows an intense shift in the UV-Vis spectra as diffuse absorption together with the variation in the optical band gap. The evaluated optical band gap values are approximately equal to the bulk band gap value of BiFeO3.
文摘Sentiment analysis is a method to identify and understand the emotion in the text through NLP and text analysis. In the era of information technology, there is often a certain error between the comments on the movie website and the actual score of the movie, and sentiment analysis technology provides a new way to solve this problem. In this paper, Python is used to obtain the movie review data from the Douban platform, and the model is constructed and trained by using naive Bayes and Bi-LSTM. According to the index, a better Bi-LSTM model is selected to classify the emotion of users’ movie reviews, and the classification results are scored according to the classification results, and compared with the real ratings on the website. According to the error of the final comparison results, the feasibility of this technology in the scoring direction of film reviews is being verified. By applying this technology, the phenomenon of film rating distortion in the information age can be prevented and the rights and interests of film and television works can be safeguarded.
文摘The results of an experimental study of long-term relaxation of the photoelectret state of polycrystalline CdTe:(Ag, Cu, Cd) and Sb<sub>2</sub>Se<sub>3</sub>:Se films with an anomalous photovoltaic property are presented. In such films, the residual photovoltage is caused by the separation of photocarriers by the built-in electrostatic field of the near-surface region of space charges and their asymmetric capture by deep levels of impurities or complexes, including impurity atoms and intrinsic defects, both in the bulk and on the surface of crystal grains. It has been shown that in activated films, a two-step exponential temporary relaxation of the initial photovoltage of the order of V<sub>APV</sub> ≈ (500-600) V is detected, and only 10% of it experiences long-term relaxation (t ≈ 100-120 min).
文摘We report the performances of a chalcopyrite Cu(In, Ga)Se<sub>2 </sub>CIGS-based thin-film solar cell with a newly employed high conductive n-Si layer. The data analysis was performed with the help of the 1D-Solar Cell Capacitance Simulator (1D-SCAPS) software program. The new device structure is based on the CIGS layer as the absorber layer, n-Si as the high conductive layer, i-In<sub>2</sub>S<sub>3</sub>, and i-ZnO as the buffer and window layers, respectively. The optimum CIGS bandgap was determined first and used to simulate and analyze the cell performance throughout the experiment. This analysis revealed that the absorber layer’s optimum bandgap value has to be 1.4 eV to achieve maximum efficiency of 22.57%. Subsequently, output solar cell parameters were analyzed as a function of CIGS layer thickness, defect density, and the operating temperature with an optimized n-Si layer. The newly modeled device has a p-CIGS/n-Si/In<sub>2</sub>S<sub>3</sub>/Al-ZnO structure. The main objective was to improve the overall cell performance while optimizing the thickness of absorber layers, defect density, bandgap, and operating temperature with the newly employed optimized n-Si layer. The increase of absorber layer thickness from 0.2 - 2 µm showed an upward trend in the cell’s performance, while the increase of defect density and operating temperature showed a downward trend in solar cell performance. This study illustrates that the proposed cell structure shows higher cell performances and can be fabricated on the lab-scale and industrial levels.
文摘AlN was used as a host material and doped with Eu grown on Si substrate by pulsed laser deposition (PLD) with low substrate temperature. The X-ray diffraction (XRD) data revealed the orientation and the composition of the thin film. The surface morphology was studied by scanning electron microscope (SEM). While raising the annealing temperatures from 300˚C to 900˚C, the emission was observed from AlN: Eu under excitation of 260 nm excitation. The photoluminescence (PL) was integrated over the visible light wavelength shifted from the blue to the red zone in the CIE 1931 chromaticity coordinates. The luminescence color coordination of AlN: Eu depending on the annealing temperatures guides the further study of Eu-doped nitrides manufacturing on white light emitting diode (LED) and full color LED devices.
文摘A boron-silicon film was formed from boron trichloride gas and dichlorosilane gas at about 900℃in ambient hydrogen at atmospheric pressure utilizing a slim vertical cold wall chemical vapor deposition reactor designed for the Minimal Fab system. The gas flow rates were 80, 20 and 0.1 - 20 sccm for the hydrogen, dichlorosilane and boron trichloride gases, respectively. The gas transport condition in the reactor was shown to quickly become stable when evaluated by quartz crystal microbalances at the inlet and outlet. The boron-silicon thin film was formed by achieving the various boron concentrations of 0.16% - 80%, the depth profile of which was flat. By observing the cross-sectional TEM image, the obtained film was dense. The boron trichloride gas is expected to be useful for the quick fabrication of various materials containing boron at significantly low and high concentrations.
