In this work, we prepared three simple arylamine-based hole transporting materials from commercially available starting materials. The effect of extending z-conjugation length or increasing the number of side groups c...In this work, we prepared three simple arylamine-based hole transporting materials from commercially available starting materials. The effect of extending z-conjugation length or increasing the number of side groups compared with reference compound on the photophysical, electrochemical, hole mobility properties and performance in perovskite solar cells were further studied. It is noted that these two kinds of molecular modifications can significantly lower the HOMO level and improve the hole mobility, thus improving the hole injection from valence band of perovskite. On the other hand, the compound with more side groups showed higher hole injection efficiency due to lower HOMO level and higher hole mo- bility compared with the compound with extending π-conjugation length. The perovskite solar cells with the modified molecules as hole transporting materials showed a higher efficiency of 15.40% and 16.95%, respectively, which is better than that of the reference compound （13.18%）. Moreover, the compound with increasing number of side groups based devices showed comparable photovoltaic performance with that of conventional spiro-OMeTAD （16.87%）.展开更多
An improved configurational-confomational statistical method is developed and the mean-square radius of gyration for atactic poly（α-methylstyrene）（PαMS） chains is studied, in which the effect of large side group...An improved configurational-confomational statistical method is developed and the mean-square radius of gyration for atactic poly（α-methylstyrene）（PαMS） chains is studied, in which the effect of large side groups is considered. The deduced formulas, based on the rotational isomer state theory, are used to investigate the configuration-dependent properties of the atactic polymer chain, and the statistical correlation of the unperturbed polymer chain dimension and structure parameters are calculated. For the fraction of meso dyads Wm= 0.4, the dependence of the radius of gyration Rg and the intrinsic viscosity [η] on the molecule mass M are Rg = 2.63×10^-2 M^0.50 nm and [η] = 7.36 × 10^-2 M^0.497, respectively, which are in agreement with the previous experimental data for the PαMS samples. A small hump is detected in the curve of the characteristic ratio of the unperturbed mean-square radius of gyration versus the chain length for short PαMS chains. The Rg increases linearly with the temperature T, and the effects of the chain length and the tacticity on the temperature coefficient are remarkable. These are quite different from the results for PαMS chains not considering side groups or for the monosubstituted polystyrene chain.展开更多
The molecules formed in a structure of A-π-D possess large hyperpolarizability β, in which A is an acceptor, D is a donor, and π is an electronic bridge connecting A and D. From such molecules one can make poled po...The molecules formed in a structure of A-π-D possess large hyperpolarizability β, in which A is an acceptor, D is a donor, and π is an electronic bridge connecting A and D. From such molecules one can make poled polymer films of large second-order展开更多
By applying non-equilibrium Green's functions (NEGF) in combination with the density functional theory (DFT), we investigate the electronic transport properties of molecular junctions constructed by OPE derivative...By applying non-equilibrium Green's functions (NEGF) in combination with the density functional theory (DFT), we investigate the electronic transport properties of molecular junctions constructed by OPE derivatives with different side groups combined C60 molecules. The results show that the side groups play an important role in the properties of electron transport. Negative differential resistance (NDR) is observed in such devices. Especially for the molecule with electron-donating group ( OCH3), two NDR appear at different bias voltage regions. And the mechanism is proposed for the NDR behavior, owing to the shift of the molecular orbitals caused by the change in molecule charge.展开更多
目的通过机器学习分析“舌边白涎”舌象特性,对舌象进行局部特征识别研究,探讨卷积神经网络算法在舌象识别应用中的性能。方法使用Python进行图像预处理,搭建用于舌象识别的视觉几何组16层(visual geometry group 16,VGG16)卷积神经网...目的通过机器学习分析“舌边白涎”舌象特性,对舌象进行局部特征识别研究,探讨卷积神经网络算法在舌象识别应用中的性能。方法使用Python进行图像预处理,搭建用于舌象识别的视觉几何组16层(visual geometry group 16,VGG16)卷积神经网络模型,分析其对“舌边白涎”舌象鉴别分析的效果,并结合热力图分析“舌边白涎”典型舌象表现。结果基于PyTorch框架,进行卷积神经网络的舌象鉴别研究,VGG16及残差网络50层(residual network 50,ResNet50)模型验证准确率均较高,达到80%以上,且ResNet50模型优于VGG16模型,可为舌象识别提供一定参考。基于加权梯度类激活映射(gradient-weighted class activation mapping,Grad-CAM)技术,通过舌苔舌色差异分布的网络可视化,有助于直观进行模型评估分析。结论基于卷积神经网络模型对舌象数据库进行分析,实现“舌边白涎”舌象识别,有助于临床诊疗的客观化辅助分析,为舌诊智能化发展提供一定借鉴。展开更多
基金supported by the National Basic Research Program of China (No. 2015CB932200)the CAS-Iranian Vice Presidency for Science and Technology Joint Research Project (No. 116134KYSB20160130)+2 种基金the Natural Science Foundation of Anhui Province (No. 1508085SMF224)the National Natural Science Foundation of China (No. 51474201)the External Cooperation Program of BIC, Chinese Academy of Sciences (No. GJHZ1607)
文摘In this work, we prepared three simple arylamine-based hole transporting materials from commercially available starting materials. The effect of extending z-conjugation length or increasing the number of side groups compared with reference compound on the photophysical, electrochemical, hole mobility properties and performance in perovskite solar cells were further studied. It is noted that these two kinds of molecular modifications can significantly lower the HOMO level and improve the hole mobility, thus improving the hole injection from valence band of perovskite. On the other hand, the compound with more side groups showed higher hole injection efficiency due to lower HOMO level and higher hole mo- bility compared with the compound with extending π-conjugation length. The perovskite solar cells with the modified molecules as hole transporting materials showed a higher efficiency of 15.40% and 16.95%, respectively, which is better than that of the reference compound （13.18%）. Moreover, the compound with increasing number of side groups based devices showed comparable photovoltaic performance with that of conventional spiro-OMeTAD （16.87%）.
文摘An improved configurational-confomational statistical method is developed and the mean-square radius of gyration for atactic poly（α-methylstyrene）（PαMS） chains is studied, in which the effect of large side groups is considered. The deduced formulas, based on the rotational isomer state theory, are used to investigate the configuration-dependent properties of the atactic polymer chain, and the statistical correlation of the unperturbed polymer chain dimension and structure parameters are calculated. For the fraction of meso dyads Wm= 0.4, the dependence of the radius of gyration Rg and the intrinsic viscosity [η] on the molecule mass M are Rg = 2.63×10^-2 M^0.50 nm and [η] = 7.36 × 10^-2 M^0.497, respectively, which are in agreement with the previous experimental data for the PαMS samples. A small hump is detected in the curve of the characteristic ratio of the unperturbed mean-square radius of gyration versus the chain length for short PαMS chains. The Rg increases linearly with the temperature T, and the effects of the chain length and the tacticity on the temperature coefficient are remarkable. These are quite different from the results for PαMS chains not considering side groups or for the monosubstituted polystyrene chain.
基金Project supported by Guangdong Provincial Science Foundation.
文摘The molecules formed in a structure of A-π-D possess large hyperpolarizability β, in which A is an acceptor, D is a donor, and π is an electronic bridge connecting A and D. From such molecules one can make poled polymer films of large second-order
基金supported by the Independent Innovative Natural Science Foundation of Shandong University (Grant No. 2009TS097)the Natural Science Foundation of Shandong Province of China (Grant Nos. ZR2009-AL004 and ZR2010AM037)
文摘By applying non-equilibrium Green's functions (NEGF) in combination with the density functional theory (DFT), we investigate the electronic transport properties of molecular junctions constructed by OPE derivatives with different side groups combined C60 molecules. The results show that the side groups play an important role in the properties of electron transport. Negative differential resistance (NDR) is observed in such devices. Especially for the molecule with electron-donating group ( OCH3), two NDR appear at different bias voltage regions. And the mechanism is proposed for the NDR behavior, owing to the shift of the molecular orbitals caused by the change in molecule charge.
文摘目的通过机器学习分析“舌边白涎”舌象特性,对舌象进行局部特征识别研究,探讨卷积神经网络算法在舌象识别应用中的性能。方法使用Python进行图像预处理,搭建用于舌象识别的视觉几何组16层(visual geometry group 16,VGG16)卷积神经网络模型,分析其对“舌边白涎”舌象鉴别分析的效果,并结合热力图分析“舌边白涎”典型舌象表现。结果基于PyTorch框架,进行卷积神经网络的舌象鉴别研究,VGG16及残差网络50层(residual network 50,ResNet50)模型验证准确率均较高,达到80%以上,且ResNet50模型优于VGG16模型,可为舌象识别提供一定参考。基于加权梯度类激活映射(gradient-weighted class activation mapping,Grad-CAM)技术,通过舌苔舌色差异分布的网络可视化,有助于直观进行模型评估分析。结论基于卷积神经网络模型对舌象数据库进行分析,实现“舌边白涎”舌象识别,有助于临床诊疗的客观化辅助分析,为舌诊智能化发展提供一定借鉴。
