Tin-lead(Sn-Pb)mixed perovskites are extensively investigated in near-infrared(NIR)photodetectors(PDs)owing to their excellent photoelectric performance.However,achieving high-performance Sn-Pb mixed PDs remains chall...Tin-lead(Sn-Pb)mixed perovskites are extensively investigated in near-infrared(NIR)photodetectors(PDs)owing to their excellent photoelectric performance.However,achieving high-performance Sn-Pb mixed PDs remains challenging,primarily because of the rapid crystallization and the susceptibility of Sn^(2+) to oxidation.To ad⁃dress these issues,this study introduces the multifunctional molecules 2,3-difluorobenzenamine(DBM)to modulate the crystallization of Sn-Pb mixed perovskites and retard the oxidation of Sn^(2+),thereby significantly enhancing film quality.Compared with the pristine film,Sn-Pb mixed perovskite films modulated by DBM molecules exhibit a high⁃ly homogeneous morphology,reduced roughness and defect density.The self-powered NIR PDs fabricated with the improved films have a spectral response range from 300 nm to 1100 nm,a peak responsivity of 0.51 A·W^(-1),a spe⁃cific detectivity as high as 2.46×10^(11)Jones within the NIR region(780 nm to 1100 nm),a linear dynamic range ex⁃ceeding 152 dB,and ultrafast rise/fall time of 123/464 ns.Thanks to the outstanding performance of PDs,the fabri⁃cated 5×5 PDs array demonstrates superior imaging ability in the NIR region up to 980 nm.This work advances the development of Sn-Pb mixed perovskites for NIR detection and paves the way for their commercialization.展开更多
The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi（NO3）3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffr...The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi（NO3）3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffraction and transmission electron microscopy, respectively. The results show that under the optimum condition that 300g/L Bi（NO3）3 reacts at 90℃ for 2h, the Bi2O3 powders with 60nm on the average and 99.5% in purity are obtained. The prepared nano-Bi2O3 powders contain a mixed crystal structure of monoclinic and triclinic instead of traditional structure of monoclinic α-Bi2O3. And the mixed crystal structure is stable in air. The reason for the appearance of the mixed crystal structure may be that the ionic radius ratio of Bi 3+ to O 2- changes easily during the formation of nano-Bi2O3 particles by a chemical precipitation method.展开更多
为探究冰晶与过冷水滴共存时的混合相结冰特性,基于FENSAP-ICE结冰计算平台,以NACA0012翼型为研究对象,采用阻力系数对非球形冰晶的运动过程进行修正,考虑了冰晶黏附效应和侵蚀效应的影响,建立了欧拉框架下冰晶运动、碰撞、黏附、结冰...为探究冰晶与过冷水滴共存时的混合相结冰特性,基于FENSAP-ICE结冰计算平台,以NACA0012翼型为研究对象,采用阻力系数对非球形冰晶的运动过程进行修正,考虑了冰晶黏附效应和侵蚀效应的影响,建立了欧拉框架下冰晶运动、碰撞、黏附、结冰和侵蚀全物理过程的混合相结冰数值计算方法。分析了冰晶质量浓度(ice water content,IWC)、液态水质量浓度(liquid water content,LWC)以及冰晶黏附和侵蚀效应对结冰形态和结冰厚度的影响规律,对比了NTI和NRC两种冰晶黏附模型的适用条件。研究结果表明:当总水含量(total water content,TWC)一定时,随着冰水含量比IWC与LWC之比的增加,结冰覆盖面积逐渐减小,最大结冰厚度先增大后减小,冰形由冠状逐渐变为尖角状,当IWC与LWC分别为0.4 g·m^(-3)和1.0 g·m^(-3)时,驻点处的结冰厚度达到最大值;对于高IWC工况,NRC黏附模型的驻点结冰厚度更接近实验结果,误差为7.2%;对于低IWC工况,NTI模型与NRC模型的驻点结冰厚度接近;侵蚀作用主要影响翼型驻点附近的区域,IWC或LWC的增大均会加剧侵蚀效应。研究可为飞行器高效防除冰系统的设计提供理论依据。展开更多
基金Supported by National Key Research and Development Program of China(2022YFA1404201)National Natural Science Foundation of China(62205187,U23A20380,U22A2091,62222509,62127817,62075120)+3 种基金Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China(IRT_17R70)Fundamental Research Program of Shanxi Province(202103021223032,202303021222031)Project Funded by China Postdoctoral Science Foundation(2022M722006)Fund for Shanxi“1331 Project”Key Subjects Construction。
文摘Tin-lead(Sn-Pb)mixed perovskites are extensively investigated in near-infrared(NIR)photodetectors(PDs)owing to their excellent photoelectric performance.However,achieving high-performance Sn-Pb mixed PDs remains challenging,primarily because of the rapid crystallization and the susceptibility of Sn^(2+) to oxidation.To ad⁃dress these issues,this study introduces the multifunctional molecules 2,3-difluorobenzenamine(DBM)to modulate the crystallization of Sn-Pb mixed perovskites and retard the oxidation of Sn^(2+),thereby significantly enhancing film quality.Compared with the pristine film,Sn-Pb mixed perovskite films modulated by DBM molecules exhibit a high⁃ly homogeneous morphology,reduced roughness and defect density.The self-powered NIR PDs fabricated with the improved films have a spectral response range from 300 nm to 1100 nm,a peak responsivity of 0.51 A·W^(-1),a spe⁃cific detectivity as high as 2.46×10^(11)Jones within the NIR region(780 nm to 1100 nm),a linear dynamic range ex⁃ceeding 152 dB,and ultrafast rise/fall time of 123/464 ns.Thanks to the outstanding performance of PDs,the fabri⁃cated 5×5 PDs array demonstrates superior imaging ability in the NIR region up to 980 nm.This work advances the development of Sn-Pb mixed perovskites for NIR detection and paves the way for their commercialization.
文摘The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi（NO3）3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffraction and transmission electron microscopy, respectively. The results show that under the optimum condition that 300g/L Bi（NO3）3 reacts at 90℃ for 2h, the Bi2O3 powders with 60nm on the average and 99.5% in purity are obtained. The prepared nano-Bi2O3 powders contain a mixed crystal structure of monoclinic and triclinic instead of traditional structure of monoclinic α-Bi2O3. And the mixed crystal structure is stable in air. The reason for the appearance of the mixed crystal structure may be that the ionic radius ratio of Bi 3+ to O 2- changes easily during the formation of nano-Bi2O3 particles by a chemical precipitation method.
文摘为探究冰晶与过冷水滴共存时的混合相结冰特性,基于FENSAP-ICE结冰计算平台,以NACA0012翼型为研究对象,采用阻力系数对非球形冰晶的运动过程进行修正,考虑了冰晶黏附效应和侵蚀效应的影响,建立了欧拉框架下冰晶运动、碰撞、黏附、结冰和侵蚀全物理过程的混合相结冰数值计算方法。分析了冰晶质量浓度(ice water content,IWC)、液态水质量浓度(liquid water content,LWC)以及冰晶黏附和侵蚀效应对结冰形态和结冰厚度的影响规律,对比了NTI和NRC两种冰晶黏附模型的适用条件。研究结果表明:当总水含量(total water content,TWC)一定时,随着冰水含量比IWC与LWC之比的增加,结冰覆盖面积逐渐减小,最大结冰厚度先增大后减小,冰形由冠状逐渐变为尖角状,当IWC与LWC分别为0.4 g·m^(-3)和1.0 g·m^(-3)时,驻点处的结冰厚度达到最大值;对于高IWC工况,NRC黏附模型的驻点结冰厚度更接近实验结果,误差为7.2%;对于低IWC工况,NTI模型与NRC模型的驻点结冰厚度接近;侵蚀作用主要影响翼型驻点附近的区域,IWC或LWC的增大均会加剧侵蚀效应。研究可为飞行器高效防除冰系统的设计提供理论依据。
