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Unraveling post-growth mechanisms of monolayer CsPbBr3 nanocubes:Laser-enhanced transformations and cathodoluminescence-electron microscopy correlations

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Journal of Energy Chemistry 2025年第01期 146-156页

作者： Mingxing Li Xiaoge Wang Xiaofan Cao Zhiqun He Chunjun Liang Mingxing Chen Jing Ju fangtian you Key Laboratory of Luminescence and Optical Information Ministry of Education Institute of Optoelectronic Technology Beijing Jiaotong University Beijing National Laboratory for Molecular Sciences (BNLMS) College of Chemistry and Molecular Engineering Peking University

Lead-halide perovskite nanoparticles（LHP NPs） are highly promising materials for next-generation displays and solid-state lighting due to their exceptional optical properties. However, their inherent instability presents a significant challenge. Recent advances have demonstrated that optoelectronic devices based on monolayer nanoparticle films exhibit both high luminescence efficiency and long-term *** research demonstrates that mobility limitations and anisotropic alignments in CsPbBr3nanocube monolayer films are key to their stabilization, hindering spontaneous growth through face-to-face fusion and resulting in the formation of connecting necks in a diagonal direction. Introducing laser irradiation confirmed this by significantly accelerating nanocubes growth, increasing mobility, and enhancing local structural ordering, leading to larger and more regularly shaped nanosheets. Fourier transform infrared spectroscopy and energy dispersive spectroscopy line-scan analyses indicated that laser irradiation did not disrupt the ligand structure. Transmission electron microscopy and correlative cathodoluminescence electron microscopy revealed the effects of post-growth and heterogeneous structures, including enhanced luminescence and inhomogeneous intensity in the nanosheets. These findings deepen the understanding of the post-growth mechanism of monolayer nanoparticles and the structure-emission correlation and highlight the unique role of laser irradiation in directing the formation of well-defined and regular nanostructures.

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Energy transfer from Ce^(3+) to Tb^(3+), Dy^(3+)and Eu^(3+) in Na_3Y(BO_3)_2

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Journal of Rare Earths 2015年第10期33卷 1051-1055页

作者：曾洪伟由芳田彭洪尚黄世华 Key Laboratory of Luminescence and Optical Information Ministry of Education Institute of Optoelectronic Technology Beijing Jiaotong University

Energy transfer is a promising strategy to improve the visible light emitting efficiency of phosphors. A series of Ce3＋, Tb3＋, Dy3＋ and/or EU3＋ doped Na3Y（BO3）2 （NYB） were prepared by solid-state reaction and their photoluminescence properties were studied in detail. The excitation and emission spectra of NYB：Ce3＋,Tb3＋ and NYB：Ce3＋,Dy3＋ revealed that an efficient energy transfer process from Ce3＋ to Zb3＋ or Dy3＋ occurred upon excitation Ce3＋ into 5d level. The dependence of the decay times of Ce3＋ 5d level on Tb3＋ or Dy3＋ concentration indicated that the energy transfer efficiency increased with increasing Tb3＋ or Dy3＋ content. So the UV excitation light could be converted into green or near-white emission. However, there was no obvious evidence of the existence of energy transfer from Ce3＋ to Eu3＋ in NYB.

关键词： lanthanide ions energy transfer Na3Y(BO3)2 visible light emitting Ce3+ rare earths

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Energy transfer and luminescent properties of Pr^(3+) and/or Dy^(3+) doped NaYF_4 and NaGdF_4

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Journal of Rare Earths 2013年第12期31卷 1125-1129页

作者：由芳田张新国彭洪尚黄世华黄艳陶冶 Key Laboratory of Luminescence and Optical Information Ministry of EducationInstitute of Optoelectronic TechnologyBeijing Jiaotong University Zhengzhou Institute of Aeronautical Industry Management Beijing Synchrotron Radiation Laboratory Institute of High Energy Physics

The phosphors that are able to convert vacuum ultraviolet（VUV） light into visible light are demanded for the development of novel displaying and lighting ***4：Pr3＋,Dy3＋,NaGdF4：Pr3＋,NaGdF4：Dy3＋and NaGdF4：Pr3＋,Dy3＋were prepared by hydrothermal synthesis method and their luminescent properties in VUV-vis spectral region were investigated at room *** NaYF4：Pr3＋,Dy3＋,no energy transfer process from Pr3＋to Dy3＋was ***,the introduction of Gd3＋into the fluoride lattice led to intense Dy3＋emissions upon Pr3＋4f5d state ***3＋acted as an intermediate,resulting in efficient energy transfer from Pr3＋to Dy3＋in ***3＋transferred most of its energy to Gd3＋,and then the energy was transferred from Gd3＋to Dy3＋.So NaGdF4：Pr3＋,Dy3＋not only took full advantage of the intense Pr3＋4f5d absorption,but converted the VUV excitation light into the near-white emission of Dy3＋.

关键词： energy transfer rare earth ions vacuum ultraviolet(VUV) 4f5d absorption

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Buried interface bridging for inverted cesium-formamidinium triiodide perovskite solar cells with long operational stability

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Science China Chemistry 2024年

作者： Chenhui Zhang Chunjun Liang Fulin Sun Ting Zhu Xinghai Huang Yuzhu Guo Xinyu Guo Kunyang Ge Dan Li fangtian you Zhiqun He Key Laboratory of Luminescence and Optical Information Ministry of Education Institute of Optoelectronic TechnologyBeijing Jiaotong University Department of Physics School of Physical Science and Engineering Beijing Jiaotong University

In the field of perovskite solar cells(PSCs), the research on defects in the buried interface has been relatively limited due to its non-exposure; however, this interface significantly impacts the performance enhancement of inverted PSCs. This study employs phenylethylammonium chloride(PEACl) molecules as a buffer layer to modify the buried interface of p-i-n structured PSCs,aiming to enhance the uniformity of self-assembled monolayers(SAMs) and facilitate the uniform nucleation and growth of perovskite films on the substrate. Furthermore, the introduction of the PEACl buffer layer effectively passivates defects at the bottom of the perovskite layer and notably enhances the crystal quality of the perovskite film by mitigating residual stress,thereby reducing nonradiative recombination loss. Following these optimizations, the MA-free PSCs treated with PEACl achieve a power conversion efficiency(PCE) of 24.11%, with significant improvements in storage, thermal stability, and operational stability. Particularly noteworthy is the device's performance in an unencapsulated state, whereas after 1,500 hours of continuous light operation stability testing, it retains 97% of its original efficiency. This study not only enriches the systematic understanding of the characteristics of the buried interface in PSCs but also contributes significantly to advancing the commercial production of perovskite photovoltaic technology.

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基于Eu^(3+)配合物纳米颗粒温敏薄膜的制备及荧光性能研究

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中国稀土学报 2010年第3期28卷 257-261页

作者：彭洪尚黄世华由芳田北京交通大学光电子技术研究所教育部发光与光学信息重点实验室北京100044

Eu3+配合物的发光具有针状发射峰、大的斯托克斯位移、长荧光寿命以及对温度高度敏感性等特点,这使得它们成为温度探针材料的最佳候选之一。合成了新型可以被可见光激发的Eu3+配合物(Eu-DT),在此基础上分别制备了基于Eu-DT分子和Eu-DT... 详细信息

Eu3+配合物的发光具有针状发射峰、大的斯托克斯位移、长荧光寿命以及对温度高度敏感性等特点,这使得它们成为温度探针材料的最佳候选之一。合成了新型可以被可见光激发的Eu3+配合物(Eu-DT),在此基础上分别制备了基于Eu-DT分子和Eu-DT纳米颗粒的温敏薄膜,并对它们的荧光寿命的温度敏感性进行了测试。这两类薄膜的荧光寿命均表现出良好的温度敏感性,特别是基于纳米颗粒的温敏薄膜,由于纳米颗粒基质的保护作用,表现出更高的荧光稳定和温度敏感性。

关键词： Eu3+配合物温敏薄膜纳米颗粒荧光寿命稀土

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NaYF_4:Pr^(3+),Er^(3+)中Pr^(3+)到Er^(3+)能量传递的研究

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科技通报 2016年第6期32卷 24-27页

作者：全立书由芳田北京交通大学光电子技术研究所发光与光信息教育部重点实验室北京100044

采用水热法合成了NaYF_4:0.3%Pr,x%Er^(3+)(X=0,2,5)系列荧光粉,并对其发光性质以及Pr^(3+)与Er^(3+)在NaYF_4基质中能量传递过程进行了研究。研究结果表明在样品中Pr^(3+)与Er^(3+)之间存在着两步能量传递,并通过荧光寿命分析了其能量... 详细信息

采用水热法合成了NaYF_4:0.3%Pr,x%Er^(3+)(X=0,2,5)系列荧光粉,并对其发光性质以及Pr^(3+)与Er^(3+)在NaYF_4基质中能量传递过程进行了研究。研究结果表明在样品中Pr^(3+)与Er^(3+)之间存在着两步能量传递,并通过荧光寿命分析了其能量传递的具体过程及其能量传递效率。

关键词： NaYF4 Pr3+ Er3+ 能量传递量子剪裁

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RbLn_2F_7的水热合成及RbLn_2F_7∶Eu^(3+)(Ln=Gd,Y)的VUV光谱

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中国稀土学报 2006年第4期24卷 391-394页

作者：由芳田黄世华王大伟黄艳徐建华发光与光信息教育部重点实验室北京交通大学光电子技术研究所北京100044 中国科学院高能物理研究所同步辐射实验室北京100039

利用水热方法合成出RbLn2F7(Ln=Gd,Y,Er,Yb和Lu),均为六方RbEr2F7型结构。掺杂Eu3+离子样品的光谱表明水热产物中氧杂质含量极低。在RbGd2F7∶Eu3+(0.5mol%)的激发光谱中只观测到Gd3+离子f-f跃迁,Eu3+离子的激发跃迁很弱。激发Gd3+离子... 详细信息

利用水热方法合成出RbLn2F7(Ln=Gd,Y,Er,Yb和Lu),均为六方RbEr2F7型结构。掺杂Eu3+离子样品的光谱表明水热产物中氧杂质含量极低。在RbGd2F7∶Eu3+(0.5mol%)的激发光谱中只观测到Gd3+离子f-f跃迁,Eu3+离子的激发跃迁很弱。激发Gd3+离子到6IJ能级后,观测到Eu3+离子的特征发射,Gd3+离子与Eu3+离子之间存在能量传递过程。Eu3+离子的5D0→7F1和5D0→7F2跃迁发射较强,表明稀土离子在六方RbLn2F7中处于非中心对称的格位。

关键词： RbLn2F7 水热合成真空紫外(VUV) 氟化物能量传递稀土

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表面对纳米微粒中稀土离子光谱性质的影响

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中国稀土学报 2007年第4期25卷 396-401页

作者：黄世华由芳田彭洪尚罗文雄冯颖吕少哲孙聆东严纯华北京交通大学光电子技术研究所发光与光信息技术教育部重点实验室北京100044 中国科学院长春光学精密机械与物理研究所激发态物理重点实验室长春130033 北京大学化学院稀土化学和应用国家重点实验室北京100871

对于稀土和过渡金属这样的离子中心,由于电子轨道的半径小,纳米尺度的限域对能级位置和跃迁速率的影响并不显著,表面效应成为这类材料与相应体材料光谱性质出现差异的主要因素。把使稀土离子光谱性质产生可测量变化的环境用一个以其为... 详细信息

对于稀土和过渡金属这样的离子中心,由于电子轨道的半径小,纳米尺度的限域对能级位置和跃迁速率的影响并不显著,表面效应成为这类材料与相应体材料光谱性质出现差异的主要因素。把使稀土离子光谱性质产生可测量变化的环境用一个以其为中心、半径为D的作用球表示,可以定义纳米材料厚度为D的表面层。用完整晶格的晶体场和一个补偿电荷的场近似描述表面层中稀土离子的晶体场。本文用这个模型分析了纳米微粒中稀土离子光谱的非均匀宽化,激光选择激发下发射光谱随激发波长的变化,非选择激发下发射光谱随温度的变化以及跃迁分支比的变化等实验现象。

关键词：纳米微粒光谱性质表面效应稀土

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SrAl_(12)O_(19):Pr^(3+)中~1S_0能级的电子-振动跃迁

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中国稀土学报 2007年第2期25卷 138-142页

作者：崔尚科黄世华由芳田王大伟贾惟义严懋勋北京交通大学光电子技术研究所发光与光信息技术教育部重点实验室波多黎各大学物理系佐治亚大学物理和天文系

稀土离子Pr3+4f2组态中的的高激发态1S0的光谱性质与其他4f2能级有显著的差别。分析了SrAl12O19∶Pr的1S0→1I6和1S0→1D2发射光谱,跃迁分别属于Δ过程和M过程;指认了其中的零声子线和电子-振动跃迁线。这两组跃迁中,电子-振动跃迁强度... 详细信息

稀土离子Pr3+4f2组态中的的高激发态1S0的光谱性质与其他4f2能级有显著的差别。分析了SrAl12O19∶Pr的1S0→1I6和1S0→1D2发射光谱,跃迁分别属于Δ过程和M过程;指认了其中的零声子线和电子-振动跃迁线。这两组跃迁中,电子-振动跃迁强度与零声子跃迁强度之比大于文献中报道的低激发态中的值,表明1S0与4f5d态的混杂增强了它的电子-声子耦合。

关键词：电子-振动跃迁电子-声子耦合 Pr^3+离子 ^1S0能级稀土

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Hydraulic support crushed mechanism for the shallow seam mining face under the roadway pillars of room mining goaf

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International Journal of Mining Science and Technology 2017年第5期27卷 853-860页

作者： Wang fangtian Duan Chaohua Tu Shihao Liang Ningning Bai Qingsheng State Key Laboratory of Coal Resources and Mine Safety China University of Mining&TechnologyXuzhou 221116China School of Mines Key Laboratory of Deep Coal Resource MiningMinistry of Education of ChinaChina University of Mining&TechnologyXuzhou 221116China School of Economics and Management Longyan UniversityLongyan 364000China

While the fully-mechanized longwall mining technology was employed in a shallow seam under a room mining goaf and overlained by thin bedrock and thick loose sands, the roadway pillars in the abandoned room mining goaf were in a stress-concentrated state, which may cause abnormal roof weighting, violent ground pressure behaviours, even roof fall and hydraulic support crushed(HSC) accidents. In this case,longwall mining safety and efficiency were seriously challenged. Based on the HSC accidents occurred during the longwall mining of 3-1-2 seam, which locates under the intersection zone of roadway pillars in the room mining goaf of 3-1-1 seam, this paper employed ground rock mechanics to analyse the overlying strata structure movement rules and presented the main influence factors and determination methods for the hydraulic support working resistance. The FLAC3 D software was used to simulate the overlying strata stress and plastic zone distribution characteristics. Field observation was implemented to contrastively analyse the hydraulic support working resistance distribution rules under the roadway pillars in strike direction, normal room mining goaf, roadway pillars in dip direction and intersection zone of roadway pillars. The results indicate that the key strata break along with rotations and reactions of the coal pillars deliver a larger concentrated load to the hydraulic support under intersection zone of roadway pillars than other conditions. The ‘‘overburden strata-key strata-roadway pillars-immediate roof" integrated load has exceeded the yield load that leads to HSC accidents. Findings in HSC mechanism provide a reasonable basis for shallow seam mining, and have important significance for the implementation of safe and efficient mining.

关键词： Shallow seam Room mining goaf Longwall mining Hydraulic support crushed mechanism Safe and efficient mining

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