To demonstrate flexible and tandem device applications,a low-temperature Cu_(2)ZnSnSe_(4)(CZTSe)deposition process,combined with efficient alkali doping,was developed.First,high-quality CZTSe films were grown at 480℃...To demonstrate flexible and tandem device applications,a low-temperature Cu_(2)ZnSnSe_(4)(CZTSe)deposition process,combined with efficient alkali doping,was developed.First,high-quality CZTSe films were grown at 480℃by a single co-evaporation,which is applicable to polyimide(PI)substrate.Because of the alkali-free substrate,Na and K alkali doping were systematically studied and optimized to precisely control the alkali distribution in CZTSe.The bulk defect density was significantly reduced by suppression of deep acceptor states after the(NaF+KF)PDTs.Through the low-temperature deposition with(NaF+KF)PDTs,the CZTSe device on glass yields the best efficiency of 8.1%with an improved Voc deficit of 646 mV.The developed deposition technologies have been applied to PI.For the first time,we report the highest efficiency of 6.92%for flexible CZTSe solar cells on PI.Additionally,CZTSe devices were utilized as bottom cells to fabricate four-terminal CZTSe/perovskite tandem cells because of a low bandgap of CZTSe(~1.0 eV)so that the tandem cell yielded an efficiency of 20%.The obtained results show that CZTSe solar cells prepared by a low-temperature process with in-situ alkali doping can be utilized for flexible thin-film solar cells as well as tandem device applications.展开更多
Climate change is making the lands a harsher environment all over the world including Pakistan. It is expected to oppose us with three main challenges： increase in temperature up to 2-5℃ （heat stress）, increasing ...Climate change is making the lands a harsher environment all over the world including Pakistan. It is expected to oppose us with three main challenges： increase in temperature up to 2-5℃ （heat stress）, increasing water stress and severe malnourishment due to climate change. It has been foreseen that there will be a 10% increase of dryland areas with climate change in the world, with more variability and incidences of short periods of extreme events （drought and heat stress）. Pearl millet is a hardy, climate smart grain crop, idyllic for environments prone to drought and heat stresses. The crop continues to produce highly nutritious grain sustainably, thereby encouraging the fight against poverty and food insecurity due to its resilience. The crop is more responsive to good production options （planting time, planting density, inter/intra row spacing, nitrogen application and irrigation）. It has high crop growth rate, large leaf area index and high radiation use efficiency that confers its high potential yield. In most of the cases, pearl millet is remained our agricultural answer to the climate calamity that we are facing, because it is selected as water saving, drought tolerant and climate change complaint crop. In view of circumstances, pearl millet cultivation must be retrieved by recognizing production options in context to changing climate scenarios of Pakistan using crop modeling techniques.展开更多
This article introduces a fastmeshless algorithm for the numerical solution nonlinear partial differential equations(PDE)by Radial Basis Functions(RBFs)approximation connected with the Total Variation(TV)-basedminimiz...This article introduces a fastmeshless algorithm for the numerical solution nonlinear partial differential equations(PDE)by Radial Basis Functions(RBFs)approximation connected with the Total Variation(TV)-basedminimization functional and to show its application to image denoising containing multiplicative noise.These capabilities used within the proposed algorithm have not only the quality of image denoising,edge preservation but also the property of minimization of staircase effect which results in blocky effects in the images.It is worth mentioning that the recommended method can be easily employed for nonlinear problems due to the lack of dependence on a mesh or integration procedure.The numerical investigations and corresponding examples prove the effectiveness of the recommended algorithm regarding the robustness and visual improvement as well as peak-signal-to-noise ratio(PSNR),signal-to-noise ratio(SNR),and structural similarity index(SSIM)corresponded to the current conventional TV-based schemes.展开更多
基金financially supported by the Korea Institute of Energy Research(KIER)(grant no.C3-2401,2402,2403)the National Research Foundation(grant no.2022M3J1A1063019)funded by the Ministry of Science and ICT
文摘To demonstrate flexible and tandem device applications,a low-temperature Cu_(2)ZnSnSe_(4)(CZTSe)deposition process,combined with efficient alkali doping,was developed.First,high-quality CZTSe films were grown at 480℃by a single co-evaporation,which is applicable to polyimide(PI)substrate.Because of the alkali-free substrate,Na and K alkali doping were systematically studied and optimized to precisely control the alkali distribution in CZTSe.The bulk defect density was significantly reduced by suppression of deep acceptor states after the(NaF+KF)PDTs.Through the low-temperature deposition with(NaF+KF)PDTs,the CZTSe device on glass yields the best efficiency of 8.1%with an improved Voc deficit of 646 mV.The developed deposition technologies have been applied to PI.For the first time,we report the highest efficiency of 6.92%for flexible CZTSe solar cells on PI.Additionally,CZTSe devices were utilized as bottom cells to fabricate four-terminal CZTSe/perovskite tandem cells because of a low bandgap of CZTSe(~1.0 eV)so that the tandem cell yielded an efficiency of 20%.The obtained results show that CZTSe solar cells prepared by a low-temperature process with in-situ alkali doping can be utilized for flexible thin-film solar cells as well as tandem device applications.
文摘Climate change is making the lands a harsher environment all over the world including Pakistan. It is expected to oppose us with three main challenges： increase in temperature up to 2-5℃ （heat stress）, increasing water stress and severe malnourishment due to climate change. It has been foreseen that there will be a 10% increase of dryland areas with climate change in the world, with more variability and incidences of short periods of extreme events （drought and heat stress）. Pearl millet is a hardy, climate smart grain crop, idyllic for environments prone to drought and heat stresses. The crop continues to produce highly nutritious grain sustainably, thereby encouraging the fight against poverty and food insecurity due to its resilience. The crop is more responsive to good production options （planting time, planting density, inter/intra row spacing, nitrogen application and irrigation）. It has high crop growth rate, large leaf area index and high radiation use efficiency that confers its high potential yield. In most of the cases, pearl millet is remained our agricultural answer to the climate calamity that we are facing, because it is selected as water saving, drought tolerant and climate change complaint crop. In view of circumstances, pearl millet cultivation must be retrieved by recognizing production options in context to changing climate scenarios of Pakistan using crop modeling techniques.
文摘This article introduces a fastmeshless algorithm for the numerical solution nonlinear partial differential equations(PDE)by Radial Basis Functions(RBFs)approximation connected with the Total Variation(TV)-basedminimization functional and to show its application to image denoising containing multiplicative noise.These capabilities used within the proposed algorithm have not only the quality of image denoising,edge preservation but also the property of minimization of staircase effect which results in blocky effects in the images.It is worth mentioning that the recommended method can be easily employed for nonlinear problems due to the lack of dependence on a mesh or integration procedure.The numerical investigations and corresponding examples prove the effectiveness of the recommended algorithm regarding the robustness and visual improvement as well as peak-signal-to-noise ratio(PSNR),signal-to-noise ratio(SNR),and structural similarity index(SSIM)corresponded to the current conventional TV-based schemes.
