The effect of the valence band tail width on the open circuit voltage of P3HT：PCBM bulk heterojunction solar cell is investigated by using the AMPS-1D computer program. An effective medium model with exponential vale...The effect of the valence band tail width on the open circuit voltage of P3HT：PCBM bulk heterojunction solar cell is investigated by using the AMPS-1D computer program. An effective medium model with exponential valence and conduction band tail states is used to simulate the photovoltaic cell. The simulation result shows that the open circuit voltage depends Iinearly on the logarithm of the generation rate and the slope depends on the width of the valence band tail. The open circuit voltage decreases with the increasing width of the band tail. The dark and light ideality factors increase with the width of the valence band tail.展开更多
Renewable energies are of major interest due to their inexhaustible and clean nature, with minimal impact on the environment. Numerous technological pathways exist in this field, each distinguished by the materials us...Renewable energies are of major interest due to their inexhaustible and clean nature, with minimal impact on the environment. Numerous technological pathways exist in this field, each distinguished by the materials used and their implementation principles. However, the cost-efficiency ratio remains a significant challenge for researchers. Currently, organic materials are gaining popularity due to their relatively low cost. However, their performance, particularly in terms of conversion efficiency, still requires improvements. This study focuses on optimizing the organic photovoltaic cell ITO/MoO3/CARAPA/PCBM/Alq3/Al using SCAPS. Several parameters were considered, such as layer thickness, recombination center density, and doping, to improve the cell’s performance. The optimal parameters obtained include an efficiency of 3%, a fill factor of 81.67%, an open-circuit voltage of 1610 mV, and a short-circuit current of 2.28 mA/cm2. The study also revealed that doping the phenyl-C61-butyric acid methyl ester (PCBM) layer has a significant impact on efficiency and short-circuit current, improving these parameters up to a certain point before causing degradation due to increased recombination. Furthermore, high doping of the tri (8-hydroxyquinoline) aluminum (Alq3) layer improves performance up to a critical threshold, after which degradation is also observed. In contrast, doping the molybdenum trioxide (MoO3) layer does not have a notable impact on cell performance. Regarding the thickness of the active Carapaprocera (CARAPA) and PCBM layers, non-optimal values lead to a decrease in performance. Similarly, an optimal thickness of the Alq3 layer significantly improves efficiency. These results highlight the importance of parameter optimization to maximize the efficiency of organic solar cells.展开更多
Combining the phase-field method and the moving boundary method,a three-dimensional phase-field simulation was conducted for the growth and grain evolution of Ti films deposited by physical vapor deposition under diff...Combining the phase-field method and the moving boundary method,a three-dimensional phase-field simulation was conducted for the growth and grain evolution of Ti films deposited by physical vapor deposition under different deposition rates and grain orientations.The evolution of grain morphology and grain orientation was also taken into consideration.Simulation results show that at lower deposition rates,the surface of the formed Ti film exhibits a distinct oriented texture structure.The surface roughness of the Ti film is positively correlated with the grain misorientation.Moreover,the surface roughness obtained from the simulation is in good agreement with the experiment results.展开更多
The core-shell structure in bulk TiNb binary alloy was designed and studied by phase-field simulations,where various core-shell structures were obtained by precise control of the initial and boundary conditions of the...The core-shell structure in bulk TiNb binary alloy was designed and studied by phase-field simulations,where various core-shell structures were obtained by precise control of the initial and boundary conditions of the TiNb binary alloy system during spinodal decomposition,and then the formation mechanism of core-shell structure was revealed.In addition,the influences of initial temperature gradient,average temperature,and initial concentration distribution of the system on the core-shell structure were investigated.Results show that the initial concentration gradient is the key factor for forming the core-shell structure.Besides,larger initial temperature gradient and higher average temperature can promote the formation of core-shell structure,which can be stabilized by adjusting the initial concentration distribution of the Nb-rich region in TiNb binary alloy.As a theoretical basis,this research provides a novel and simple strategy for the preparation of TiNb-based alloys and other materials with peculiar core-shell structures and desirable mechanical and physical properties.展开更多
文摘The effect of the valence band tail width on the open circuit voltage of P3HT：PCBM bulk heterojunction solar cell is investigated by using the AMPS-1D computer program. An effective medium model with exponential valence and conduction band tail states is used to simulate the photovoltaic cell. The simulation result shows that the open circuit voltage depends Iinearly on the logarithm of the generation rate and the slope depends on the width of the valence band tail. The open circuit voltage decreases with the increasing width of the band tail. The dark and light ideality factors increase with the width of the valence band tail.
文摘Renewable energies are of major interest due to their inexhaustible and clean nature, with minimal impact on the environment. Numerous technological pathways exist in this field, each distinguished by the materials used and their implementation principles. However, the cost-efficiency ratio remains a significant challenge for researchers. Currently, organic materials are gaining popularity due to their relatively low cost. However, their performance, particularly in terms of conversion efficiency, still requires improvements. This study focuses on optimizing the organic photovoltaic cell ITO/MoO3/CARAPA/PCBM/Alq3/Al using SCAPS. Several parameters were considered, such as layer thickness, recombination center density, and doping, to improve the cell’s performance. The optimal parameters obtained include an efficiency of 3%, a fill factor of 81.67%, an open-circuit voltage of 1610 mV, and a short-circuit current of 2.28 mA/cm2. The study also revealed that doping the phenyl-C61-butyric acid methyl ester (PCBM) layer has a significant impact on efficiency and short-circuit current, improving these parameters up to a certain point before causing degradation due to increased recombination. Furthermore, high doping of the tri (8-hydroxyquinoline) aluminum (Alq3) layer improves performance up to a critical threshold, after which degradation is also observed. In contrast, doping the molybdenum trioxide (MoO3) layer does not have a notable impact on cell performance. Regarding the thickness of the active Carapaprocera (CARAPA) and PCBM layers, non-optimal values lead to a decrease in performance. Similarly, an optimal thickness of the Alq3 layer significantly improves efficiency. These results highlight the importance of parameter optimization to maximize the efficiency of organic solar cells.
文摘针对不同底纹背景颜色的印制电路板(printed circuit board,PCB)微小缺陷检测样本少、效率低、检测算法参数量大和精度低的问题,本文基于YOLOv8n框架提出了一种轻量化检测模型PCB-YOLO。首先,对原始的多种颜色背景的大幅面PCB数据集进行数据预处理,通过灰度变换和切片操作得到适合YOLOv8输入尺寸的PCB数据和降低颜色背景干扰影响,防止PCB的微小缺陷在缩放的过程中丢失;其次,考虑到PCB存在小目标缺陷的占比较大问题,通过结合SimAM注意力机制和合并切片操作,设计Conv_SWS(SimAM with slicing)模块,替代传统的下采样方式,保留小目标的关键信息,从而增强PCB中微小目标缺陷的特征提取并提高检测准确性;然后,对YOLOv8中原有的C2f模块进行改造,引入部分卷积(PConv)对关键特征通道进行综合计算,设计FBC2f模块,用于增强特征提取能力并减少模型参数量;最后,采用基于Wasserstein距离的度量标准NWD(normalized Wasserstein distance)与标准IoU(intersection over union)结合改进损失函数来加速模型收敛,进一步提高YOLOv8对微小目标的检测能力。实验结果表明,与原始的YOLOv8n相比,在PCB缺陷检测数据集上的PCB-YOLO模型的参数减少了23.6%,mAP50提高了2.9%,达到95.6%。在工业铝片表面缺陷、PKU-Market-PCB缺陷数据集上的泛化性实验也验证了PCB-YOLO模型的有效性。
文摘印刷电路板(Printed Circuit Board,PCB)缺陷会造成巨额经济损失与安全隐患,传统的检测方法精度和效率都较为低下,现有的深度学习模型在面对复杂背景下的小目标检测时存在明显的不足。文章针对YOLOv10在PCB中的检测性能不足,在主干网络采用SPD-Conv模块替代传统卷积,通过维度重排保留小目标的特征并且降低背景干扰。在颈部网络的C2f模块中嵌入SE注意力机制,构建C2f_SE模块提升特征区分度。文章在北京大学PCB数据集的基础上,通过镜像、旋转等数据增强后将数据集扩展至6930张。实验结果表明,改进模型平均精度均值(mean Average Precision,mAP)达98.1%,较原始YOLOv10提升4.7%,其中鼠咬、毛刺等小目标缺陷检测精度提升明显。该模型为工业场景PCB缺陷检测提供了高效可靠方案。
基金National MCF Energy R&D Program of China(2018YFE0306100)Natural Science Foundation of Hunan Province for Distinguished Young Scholars(2021JJ10062)+1 种基金National Natural Science Foundation of China(52101028)China Postdoctoral Science Foundation(2021M703628)。
文摘Combining the phase-field method and the moving boundary method,a three-dimensional phase-field simulation was conducted for the growth and grain evolution of Ti films deposited by physical vapor deposition under different deposition rates and grain orientations.The evolution of grain morphology and grain orientation was also taken into consideration.Simulation results show that at lower deposition rates,the surface of the formed Ti film exhibits a distinct oriented texture structure.The surface roughness of the Ti film is positively correlated with the grain misorientation.Moreover,the surface roughness obtained from the simulation is in good agreement with the experiment results.
基金National Natural Science Foundation of China(12372152)Guangdong Basic and Applied Basic Research Foundation(2023A1515011819,2024A1515012469)Shandong Provincial Natural Science Foundation(ZR2023MA058)。
文摘The core-shell structure in bulk TiNb binary alloy was designed and studied by phase-field simulations,where various core-shell structures were obtained by precise control of the initial and boundary conditions of the TiNb binary alloy system during spinodal decomposition,and then the formation mechanism of core-shell structure was revealed.In addition,the influences of initial temperature gradient,average temperature,and initial concentration distribution of the system on the core-shell structure were investigated.Results show that the initial concentration gradient is the key factor for forming the core-shell structure.Besides,larger initial temperature gradient and higher average temperature can promote the formation of core-shell structure,which can be stabilized by adjusting the initial concentration distribution of the Nb-rich region in TiNb binary alloy.As a theoretical basis,this research provides a novel and simple strategy for the preparation of TiNb-based alloys and other materials with peculiar core-shell structures and desirable mechanical and physical properties.
