An optimum design of a-Si:H(n)/a-Si:H(i)/c-Si(p)heterojunction solar cell is realized with 24.27%conversion efficiency by gradient doping of the a-Si:H(n)layer.The photovoltaic properties are simulated by the AFORS-HE...An optimum design of a-Si:H(n)/a-Si:H(i)/c-Si(p)heterojunction solar cell is realized with 24.27%conversion efficiency by gradient doping of the a-Si:H(n)layer.The photovoltaic properties are simulated by the AFORS-HET software.Besides the additional electric field caused by the gradient doping,the enhanced and widen spectral response also improves the solar cell performance compared with the uniform-doping mode.The simulation shows that the gradient doping is efficient to improve the photovoltaic performance of the solar cells.The study is valuable for the solar cell design with excellent performances.展开更多
We report on the mechanism of the dielectric properties of oxygen vacancy in ZnO,using ab initio numerical simulations of oxygen vacancy on the band structure and dielectric properties,to develop photoelectric materia...We report on the mechanism of the dielectric properties of oxygen vacancy in ZnO,using ab initio numerical simulations of oxygen vacancy on the band structure and dielectric properties,to develop photoelectric material applications.It is revealed that the appearance of oxygen vacancies leads to wider energy band gap,obvious blue shift and increase in the peak of dielectric function as compared to the intrinsic ZnO simulation.We explain these unusual phenomena and analyze the dielectric changes with the mechanism of polarization in the semiconductors.It is shown that the main mechanism of influencing dielectric properties is the electron displacement polarization.The result may be helpful for development of photoelectric materials.展开更多
The high-temperature permittivity of quartz fibre-reinforced silicon dioxide (SiO2/SiO2 ) nano-composites is studied on the basis of the multi-scale theoretical model.We obtain the permittivity of the SiO2/SiO2 at hig...The high-temperature permittivity of quartz fibre-reinforced silicon dioxide (SiO2/SiO2 ) nano-composites is studied on the basis of the multi-scale theoretical model.We obtain the permittivity of the SiO2/SiO2 at high temperature,which is dependent on the temperature by data-mining.The result shows that the permittivity and loss tangent obtained by data-mining are well consistent with the measured ones.The high-temperature permittivity can be well predicted for SiO2/SiO2 by the as-proposed model and the data-mining method.展开更多
The first-principles numerical simulation is employed-to calculate the effect of replacement of carbon and silicon with boron on the electronic structure and optical properties of β-SiC.Mulliken analysis shows that t...The first-principles numerical simulation is employed-to calculate the effect of replacement of carbon and silicon with boron on the electronic structure and optical properties of β-SiC.Mulliken analysis shows that the B impurity bond lengths shrink in the case of Bsi,while they expand with reference to Bc.In addition,Bsi contains C-C,Si-Si and B-Si bonds.The calculated results show that the two systems of Bc and Bsi apply different dispersion.Bc is in accordance with the Lorentz dispersion theory while Bsi follows the Drude dispersion theory.Theoretic analysis and quantitative calculation are used for conductivity spectra in the infrared region.展开更多
基金Supported by the Natural Science Foundation of Hebei Province under Grant Nos A2012203016,A2012203174Scientific Research Project of HPCE under Grant No Z2009114Technology Research and Development Program of QHD(No 201101A110).
文摘An optimum design of a-Si:H(n)/a-Si:H(i)/c-Si(p)heterojunction solar cell is realized with 24.27%conversion efficiency by gradient doping of the a-Si:H(n)layer.The photovoltaic properties are simulated by the AFORS-HET software.Besides the additional electric field caused by the gradient doping,the enhanced and widen spectral response also improves the solar cell performance compared with the uniform-doping mode.The simulation shows that the gradient doping is efficient to improve the photovoltaic performance of the solar cells.The study is valuable for the solar cell design with excellent performances.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50972014 and 50872159.
文摘We report on the mechanism of the dielectric properties of oxygen vacancy in ZnO,using ab initio numerical simulations of oxygen vacancy on the band structure and dielectric properties,to develop photoelectric material applications.It is revealed that the appearance of oxygen vacancies leads to wider energy band gap,obvious blue shift and increase in the peak of dielectric function as compared to the intrinsic ZnO simulation.We explain these unusual phenomena and analyze the dielectric changes with the mechanism of polarization in the semiconductors.It is shown that the main mechanism of influencing dielectric properties is the electron displacement polarization.The result may be helpful for development of photoelectric materials.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50872159,50972014,51072024 and 51132002.
文摘The high-temperature permittivity of quartz fibre-reinforced silicon dioxide (SiO2/SiO2 ) nano-composites is studied on the basis of the multi-scale theoretical model.We obtain the permittivity of the SiO2/SiO2 at high temperature,which is dependent on the temperature by data-mining.The result shows that the permittivity and loss tangent obtained by data-mining are well consistent with the measured ones.The high-temperature permittivity can be well predicted for SiO2/SiO2 by the as-proposed model and the data-mining method.
基金Supported by the State Key Program of the National Natural Science Foundation of China under Grant No 51132002the National Natural Science Foundation of China under Grant No 50972015the Natural Science Foundation of Hebei Province under Grant No A2011203026.
文摘The first-principles numerical simulation is employed-to calculate the effect of replacement of carbon and silicon with boron on the electronic structure and optical properties of β-SiC.Mulliken analysis shows that the B impurity bond lengths shrink in the case of Bsi,while they expand with reference to Bc.In addition,Bsi contains C-C,Si-Si and B-Si bonds.The calculated results show that the two systems of Bc and Bsi apply different dispersion.Bc is in accordance with the Lorentz dispersion theory while Bsi follows the Drude dispersion theory.Theoretic analysis and quantitative calculation are used for conductivity spectra in the infrared region.
