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1.
最近报道的卤化物钙钛矿具有光致发光量子产率高、发射带窄的特性,可作为一种新 型X 射线探测材料,但仍存在光和热稳定性低、铅毒性等问题。本文研究一种低温溶液法 制备的无机非铅钙钛矿Cs3Cu2I5纳米晶材料,分析其在X射线辐射下的发光特性, 并探究 不同厚度Cs3Cu2I5纳米晶材料的转换效率与X 射线源管电压之间的关系。在成像实 验中, 本文设计一种高效的Cs3Cu2I5材料闪烁体转换屏,研制基于Cs3Cu2I5材料闪烁 体转换屏的X 射线成像系统,分别对剃须刀刀片和蜗牛壳进行X射线成像。实验结果表明:在X射线辐 射下钙钛矿Cs3Cu2I5的发射峰在波长为460 nm时达到峰值;在 厚度为0.30 mm 时, Cs3Cu2I5材料转换效率较高;成像结果显示图像轮廓清晰、物体内部结构层次分明 。研究 表明:非铅钙钛矿Cs3Cu2I5纳米晶材料可以作为一种新型闪烁体,在X射线探测与成 像 方面有着巨大的应用潜力。 相似文献
2.
InGaAs光电探测器广泛应用于短波红外检测。在InGaAs中掺入Bi可以减小带隙,延长探测波长。通过控制In和Bi的组分可使InyGa1-yAs1-xBix与InP晶格匹配,同时,扩展探测波长至3 μm以上。设计并研究了In0.394Ga0.606As0.913Bi0.087 p-i-n光电探测器的光电性能。计算了不同温度、吸收层厚度和p(n)区掺杂浓度下的暗电流和响应率特性。获得了3 μm的截止波长。该结构为拓展InP基晶格匹配的短波红外探测器的探测波长提供了一种可行的方法。 相似文献
3.
采用两步水热法在导电玻璃(FTO)上制备了WO3/NiWO4复合薄膜。通过XRD,SEM表征了WO3/NiWO4复合薄膜的组成结构及微观形貌,利用UV-Vis、光电流测试、光电催化测试和交流阻抗测试分析了WO3/NiWO4复合薄膜的光电性能。结果表明:WO3/NiWO4复合薄膜相较于WO3薄膜具有更好的光吸收特性、光电流密度和光电催化活性,其中水热反应3h的WO3/NiWO4复合薄膜的光电化学性能最佳。WO3/NiWO4-3h在1.4V(vs.Ag/AgCl)时的光电流密度为1.94mA/cm2,光电催化210min对亚甲基蓝溶液的降解效率为57.1%。交流阻抗图谱表明WO3/NiWO4薄膜的电荷转移电阻小于WO3薄膜,光电化学性能更优。 相似文献
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5.
结合水热法和阳极氧化法合成了Sb2S3/TiO2纳米管异质结阵列,采用场发射扫描电子显微镜、X射线衍射谱表征了异质结阵列的形貌和晶体结构。暗态下的电流-电压曲线表明Sb2S3/TiO2纳米管异质结阵列具有整流效应。相比于纯的TiO2纳米管阵列,Sb2S3/TiO2纳米管异质结阵列的光电性能有了显著的提升:在AM 1.5标准光强作用下,光电转换效率从0.07%增长到0.40%,表面光电压响应范围从紫外光区拓宽至可见光区。结合表面光电压谱和相位谱,分析了Sb2S3/TiO2纳米管异质结阵列中光生载流子的分离和传输性能。 更多还原 相似文献
6.
有机-无机压电材料是一种分子铁电体,具有柔性、结构灵活、易成膜、全液相合成及环保节能等优点,可满足新一代薄膜器件及可穿戴设备的需求。该文以三甲基卤代甲基铵(TMXM, X=F, Cl, Br)为有机部分,MnCl2为无机部分,通过溶液蒸发法制备了具有钙钛矿分子结构的有机-无机压电材料三甲基氯三氯化锰(TMCM-MnCl3),并对其分子结构组成、压电、热学、声学及铁电性进行表征。结果表明,TMCM-MnCl3的压电常数为106 pC/N,居里温度为130 ℃,声阻抗值约为16.5 MRayl,低于压电陶瓷PZT-4(大于33 MRayl),具有广阔的应用前景。 相似文献
7.
碳电极具有成本低、印刷方便、可有效隔离水氧等优点,因此有望利用碳电极材料实现低成本、高稳定性的钙钛矿太阳电池。无空穴传输层的传统碳基钙钛矿太阳电池面临着空穴提取率低、电子逆向传输,钙钛矿和碳电极界面的载流子复合等问题。文章引入聚(3-己基噻吩)(P3HT)作为器件的空穴传输层,使碳基钙钛矿太阳电池ITO/SnO2/MAPbI3/P3HT/Carbon的光伏性能得到了显著改善:器件的光电转化效率从11.16% 提高到13.37%。在氮气环境下,连续光照1000h,太阳电池的光电转化效率可保持初始值的87%,而传统器件在光照500h后,其光电转化效率已下降至初始值的60%。 相似文献
8.
本文首次通过旋涂热解偏钨酸铵((NH4)6H2W12O40)的DMF/水溶液成功制备了致密的三氧化钨(WO3)薄膜, 系统研究了WO3薄膜厚度及用异丙醇冲洗处理气相辅助溶液法制备的CH3NH3PbI3薄膜对相应钙钛矿太阳电池光伏性能的影响. 结果表明, 使用厚度为62nmWO3致密层的平板钙钛矿太阳电池获得了短路电流密度17.39 mA.cm-2, 开路电压0.58 V, 填充因子0.57, 相应光电转化效率5.72%. 使用异丙醇冲洗CH3NH3PbI3薄膜后, 相应太阳电池的光电转化效率由5.72 % 升高到7.04 %. 相似文献
9.
基于光栅效应的二维材料垂直结构可实现高灵敏度和宽光谱光探测器。本文报告了一种基于硒化铟(InSe)/二碲化钼(MoTe2)垂直异质结构的高灵敏度光电探测器,该探测器在 365~965 nm 波长范围内具有出色的宽光谱探测能力。顶层的InSe用作调节沟道电流的光栅层,MoTe2 则用作传输层。通过结合两种材料的优势,该光电探测器的响应时间为 21.6 ms,比探测率在365 nm光照下可以达到1.05×1013 Jones,在965nm光照下也可达到109 Jones数量级。外量子效率可达 1.03×105%,显示出强大的光电转换能力。 相似文献
10.
本文研究了In0.83Al0.17As/In0.52Al0.48As数字递变异变缓冲层结构(DGMB)的总周期数对2.6 μm延伸波长In0.83Ga0.17As光电二极管性能的影响。实验表明,在保持总缓冲层厚度不变的情况下,通过将在InP衬底上生长的In0.83Al0.17As/In0.52Al0.48As DGMB结构的总周期数从19增加到38,其上所生长的In0.83Ga0.17As/In0.83Al0.17As光电二极管材料层的晶体质量得到了显著改善。对于在总周期数为38的DGMB上外延的In0.83Ga0.17As光电二极管,观察到其应变弛豫度增加到99.8%,表面粗糙度降低,光致发光强度和光响应度均增强,同时暗电流水平被显著抑制。这些结果表明,随着总周期数目的增加,DGMB可以更有效地抑制穿透位错的传递并降低残余缺陷密度。 相似文献
11.
Embedding Perovskite Nanocrystals into a Polymer Matrix for Tunable Luminescence Probes in Cell Imaging
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Haihua Zhang Xu Wang Qing Liao Zhenzhen Xu Haiyang Li Lemin Zheng Hongbing Fu 《Advanced functional materials》2017,27(7)
Lead halide perovskite nanocrystals (NCs) with bright luminescence and broad spectral tunability are good candidates as smart probes for bioimaging, but suffer from hydrolysis even when exposed to atmosphere moisture. In this paper, a strategy is demonstrated by embedding CsPbX3 (X = Cl, Br, I) NCs into microhemispheres (MHSs) of polystyrene matrix to prepare “water‐resistant” NCs@MHSs hybrids as multicolor multiplexed optical coding agents. First, a facile room‐temperature solution self‐assembly approach to highly luminescent colloidal CsPbX3 NCs is developed by injecting a stock solution of CsX?PbX2 in N ,N ‐dimethylformamide into dichloromethane. Polyvinyl pyrrolidone (PVP) is chosen as the capping ligand, which is physically adsorbed and wrapped on the surface of perovskite NCs to form a protective layer. The PVP protective layer not only leads to composition‐tunable CsPbX3 NCs with high quantum yields and narrow emission linewidths of 12–34 nm but also acts as an interfacial layer, making perovskite NCs compatible with polystyrene polymers and facilitating the next step to embed CsPbX3 NCs into polymer MHSs. CsPbX3 NCs@MHSs are demonstrated as multicolor luminescence probes in live cells with high stability and nontoxicity. Using ten intensity levels and seven‐color NCs@MHSs that show non‐overlapping spectra, it will be possible to individually tag about ten million cells. 相似文献
12.
Shuxin Chen Jidong Lin Song Zheng Yuanhui Zheng Daqin Chen 《Advanced functional materials》2023,33(18):2213442
High-quality backlit display puts forward urgent demand for color-converting materials. Recently, metal halide perovskites (MHPs) with full spectral tunability, high photoluminescence quantum yields (PLQYs), and high color purity have found potential application in wide-color-gamut display. Regrettably, naked MHPs suffer from long-term instable issue and cannot pass harsh stability tests. Herein, amorphous-glass-protected green/red CsPbX3 quantum dots (QDs) are prepared by elaborately optimizing glass structure, perovskite concentration, and in situ crystallization. PLQYs of green CsPbBr3@glass and red CsPbBr1.5I1.5@glass reach 94% and 78%, respectively, which are the highest ones of CsPbX3@glass composites reported so far and comparable to colloidal counterparts. Benefited from complete isolation of QDs from external environment by glass network, CsPbX3@glass can endure harsh commercial standard aging tests of 85 °C/85%RH and blue-light-irradiation, which are applied to construct white light-emitting diodes (wLEDs) with high external quantum efficiency of 13.8% and ultra-high luminance of 500 000 cd m−2. Accordingly, the perovskite wLED arrays-based backlit unit and a prototype display device are designed for the first time, showing more vivid and wide-color-gamut feature benefited from narrowband emissions of CsPbX3 QDs. This work highlights practical application of CsPbX3@glass composite as an efficient and stable light color converter in backlit display. 相似文献
13.
Solvothermal Synthesis of High‐Quality All‐Inorganic Cesium Lead Halide Perovskite Nanocrystals: From Nanocube to Ultrathin Nanowire
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Min Chen Yatao Zou Linzhong Wu Qi Pan Di Yang Huicheng Hu Yeshu Tan Qixuan Zhong Yong Xu Haiyu Liu Baoquan Sun Qiao Zhang 《Advanced functional materials》2017,27(23)
Recently, all‐inorganic cesium lead halide (CsPbX3, X = Cl, Br, I) perovskite nanocrystals have drawn much attention because of their outstanding photophysical properties and potential applications. In this work, a simple and efficient solvothermal approach to prepare CsPbX3 nanocrystals with tunable and bright photoluminescent (PL) properties, controllable composition, and morphology is presented. CsPbX3 nanocubes are successfully prepared with bright emission high PL quantum yield up to 80% covering the full visible range and narrow emission line widths (from 12 to 36 nm). More importantly, ultrathin CsPbX3 (X = Cl/Br, Br, and Br/I) nanowires (with diameter as small as ≈2.6 nm) can be prepared in a very high morphological yield (almost 100%). A strong quantum confinement effect is observed in the ultrathin nanowires, in which both the absorption and emission peaks shift to shorter wavelength range compared to their bulk bandgap. The reaction parameters, such as temperature and precursors, are varied to investigate the growth process. A white light‐emitting device prototype device with wide color gamut covering up to 120% of the National Television System Committee standard has been demonstrated by using CsPbBr3 nanocrystals as the green light source. The method in this study provides a simple and efficient way to prepare high‐quality CsPbX3 nanocrystals. 相似文献
14.
Solvent‐Polarity‐Engineered Controllable Synthesis of Highly Fluorescent Cesium Lead Halide Perovskite Quantum Dots and Their Use in White Light‐Emitting Diodes
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Guopeng Li Hui Wang Ting Zhang Longfei Mi Yugang Zhang Zhongping Zhang Wenjun Zhang Yang Jiang 《Advanced functional materials》2016,26(46):8478-8486
Cesium lead halide quantum dots (QDs) have tunable photoluminescence that is capable of covering the entire visible spectrum and have high quantum yields, which make them a new fluorescent materials for various applications. Here, the synthesis of CsPbX3 (X = Cl, Br, I, or mixed Cl/Br and Br/I) QDs by direct ion reactions in ether solvents is reported, and for the first time the synergetic effects of solvent polarity and reaction temperature on the nucleation and growth of QDs are demonstrated. The use of solvent with a low polarity enables controlled growth of QDs, which facilitates the synthesis of high‐quality CsPbX3 QDs with broadly tunable luminescence, narrow emission width, and high quantum yield. A QD white LED (WLED) is demonstrated by coating the highly fluorescent green‐emissive CsPbBr3 QDs together with red phosphors on a blue InGaN chip, which presents excellent warm white light emission with a high rendering index of 93.2 and color temperature of 5447 K, suggesting the potential applications of highly fluorescent cesium lead halide perovskite QDs as an alternative color converter in the fabrication of WLEDs. 相似文献
15.
《Advanced functional materials》2017,27(21)
Recent synthetic developments have generated intense interest in the use of cesium lead halide perovskite nanocrystals for light‐emitting applications. This work presents the photoluminescence (PL) of cesium lead halide perovskite nanocrystals with tunable halide composition recorded as function of temperature from 80 to 550 K. CsPbBr3 nanocrystals show the highest resilience to temperature while chloride‐containing samples show relatively poorer preservation of photoluminescence at elevated temperatures. Thermal cycling experiments show that PL loss of CsPbBr3 is largely reversible at temperatures below 450 K, but shows irreversible degradation at higher temperatures. Time‐resolved measurements of CsPbX3 samples show an increase in the PL lifetime with temperature elevation, consistent with exciton fission to form free carriers, followed by a decrease in the apparent PL lifetime due to trapping. PL persistence measurements and time‐resolved spectroscopies implicate thermally assisted trapping, most likely to halogen vacancy traps, as the mechanism of reversible PL loss. 相似文献
16.
Solution‐Processed Low Threshold Vertical Cavity Surface Emitting Lasers from All‐Inorganic Perovskite Nanocrystals
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Yue Wang Xiaoming Li Venkatram Nalla Haibo Zeng Handong Sun 《Advanced functional materials》2017,27(13)
Recently, newly engineered all‐inorganic cesium lead halide perovskite nanocrystals (IPNCs) (CsPbX3, X = Cl, Br, I) are discovered to possess superior optical gain properties appealing for solution‐processed cost‐effective lasers. Yet, the potential of such materials has not been exploited for practical laser devices, rendering the prospect as laser media elusive. Herein, the challenging but practically desirable vertical cavity surface emitting lasers (VCSELs) based on the CsPbX3 IPNCs, featuring low threshold (9 µJ cm?2), directional output (beam divergence of ≈3.6°), and favorable stability, are realized for the first time. Notably, the lasing wavelength can be tuned across the red, green, and blue region maintaining comparable thresholds, which is promising in developing single‐source‐pumped full‐color visible lasers. It is fully demonstrated that the characteristics of the VCSELs can be versatilely engineered by independent adjustment of the cavity and solution‐processable nanocrystals. The results unambiguously reveal the feasibility of the emerging CsPbX3 IPNCs as practical laser media and represent a significant leap toward CsPbX3 IPNC‐based laser devices. 相似文献
17.
Air‐Stable Cesium Lead Iodide Perovskite for Ultra‐Low Operating Voltage Resistive Switching
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Ji Su Han Quyet Van Le Jaeho Choi Kootak Hong Cheon Woo Moon Taemin Ludvic Kim Hyojung Kim Soo Young Kim Ho Won Jang 《Advanced functional materials》2018,28(5)
CsPbX3 (X = halide, Cl, Br, or I) all‐inorganic halide perovskites (IHPs) are regarded as promising functional materials because of their tunable optoelectronic characteristics and superior stability to organic–inorganic hybrid halide perovskites. Herein, nonvolatile resistive switching (RS) memory devices based on all‐inorganic CsPbI3 perovskite are reported. An air‐stable CsPbI3 perovskite film with a thickness of only 200 nm is successfully synthesized on a platinum‐coated silicon substrate using low temperature all‐solution process. The RS memory devices of Ag/polymethylmethacrylate (PMMA)/CsPbI3/Pt/Ti/SiO2/Si structure exhibit reproducible and reliable bipolar switching characteristics with an ultralow operating voltage (<+0.2 V), high on/off ratio (>106), reversible RS by pulse voltage operation (pulse duration < 1 ms), and multilevel data storage. The mechanical flexibility of the CsPbI3 perovskite RS memory device on a flexible substrate is also successfully confirmed. With analyzing the influence of phase transition in CsPbI3 on RS characteristics, a mechanism involving conducting filaments formed by metal cation migration is proposed to explain the RS behavior of the memory device. This study will contribute to the understanding of the intrinsic characteristics of IHPs for low‐voltage resistive switching and demonstrate the huge potential of them for use in low‐power consumption nonvolatile memory devices on next‐generation computing systems. 相似文献
18.
Yifan Wang Feng Yang Xuanze Li Fan Ru Pei Liu Li Wang Wei Ji Jing Xia Xiangmin Meng 《Advanced functional materials》2019,29(43)
Inorganic cesium lead halide perovskite (CsPbX3, X = Cl, Br, I) is a promising material for developing novel electronic and optoelectronic devices. Despite the substantial progress that has been made in the development of large perovskite single crystals, the fabrication of high‐quality 2D perovskite single‐crystal films, especially perovskite with a low symmetry, still remains a challenge. Herein, large‐scale orthorhombic CsPbBr3 single‐crystal thin films on zinc‐blende ZnSe crystals are synthesized via vapor‐phase epitaxy. Structural characterizations reveal a “CsPbBr3(110)//ZnSe(100), CsPbBr3[?110]//ZnSe[001] and CsPbBr3[001]//ZnSe[010]” heteroepitaxial relationship between the covering CsPbBr3 layer and the ZnSe growth substrate. It is exciting that the epitaxial film presents an in‐plane anisotropic absorption property from 350 to 535 nm and polarization‐dependent photoluminescence. Photodetectors based on the epitaxial film exhibit a high photoresponsivity of 200 A W?1, a large on/off current ratio exceeding 104, a fast photoresponse time of about 20 ms, and good repeatability at room temperature. Importantly, a strong polarization‐dependent photoresponse is also found on the device fabricated using the epitaxial CsPbBr3 film, making the orthorhombic perovskite promising building blocks for optoelectronic devices featured with anisotropy. 相似文献
19.
Meng Fan Jinpeng Huang Lyudmila Turyanska Zhenfeng Bian Liancheng Wang Chunyang Xu Nan Liu Hongbo Li Xiaoyu Zhang Chengxi Zhang Xuyong Yang 《Advanced functional materials》2023,33(19):2215032
Metal halide perovskite quantum dots (QDs) have emerged as potential materials for high brightness, wide color gamut, and cost-effective backlight emission due to their high photoluminescence quantum yields, narrow emission linewidths, and tunable bandgaps. Herein, CsPbX3/SBA-15 nanocomposites are prepared with outstanding optical properties and high stability through an in situ growth strategy using mesoporous silica particles. According to finite-difference time-domain simulations, the mesoporous structure provides a strong waveguide effect on perovskite QDs and the uniform dispersion suppresses reabsorption losses, improving the overall photoconversion efficiency of perovskite QDs. The as-fabricated perovskite monochromatic light-emitting diode (LED) has a maximum luminous efficiency of 183 lm W−1, which is the highest for monochromatic perovskite LEDs reported to date. A further benefit of this work is that the white devices, which combine the green and red perovskite nanocomposites with commercial blue LED, exhibit a high luminous efficiency of 116 lm W−1 and a wide color gamut (125% for NTSC and 94% for Rec. 2020) with coordinates of (0.33,0.31). 相似文献
20.
Employing Polar Solvent Controlled Ionization in Precursors for Synthesis of High‐Quality Inorganic Perovskite Nanocrystals at Room Temperature
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Fan Fang Wei Chen Yang Li Haochen Liu Ming Mei Ruan Zhang Junjie Hao Marus Mikita Wanqiang Cao Ruikun Pan Kai Wang Xiao Wei Sun 《Advanced functional materials》2018,28(10)
All inorganic cesium lead halide (CsPbX3, X = Cl, Br, I) perovskite nanocrystals (PeNCs) are synthesized by employing polar solvent controlled ionization (PCI) method in precursors. The new strategy can be easily carried out at room temperature and allow to employ smaller amount of weaker polarity and a broader range of low‐boiling low‐toxic solvents. The as prepared CsPbX3 PeNCs reveal tunable emission spectra from 380 to 700 nm and high quantum yields over 80% with narrow full width at half maximum (FWHM). Meanwhile, larger “effective Stokes shifts” of PeNCs in PCI method, which enlarges 200% more than other PeNCs in regular methods, are observed. Most interestingly, the PeNCs growth process is coupling with some typical crystals formations. The main morphologies of CsPbI3 PeNCs are hybrid of nanorods and nanoparticles. The primary morphologies of CsPbBrxI3‐x and CsPbBr3 PeNCs are nanowires, which are supposed to have great potentials for applying in laser arrays and highly sensitive photodetector applications. Furthermore, such superior optical is endowed to fabricate white light emitting diodes, which has wide color gamut covering up to 120% of the National Television Systems Committee color standard. 相似文献