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利用稳态荧光谱和时间分辨荧光技术研究了温度对半花菁Langmuir-Blodgett(LB)多层膜光致荧光特性的影响.半花菁分子在半花菁/花生酸、半花菁/花生酸镉交替及纯半花菁Z-型LB多层膜中均形成了H-聚集体,加热能使聚集体部分离解.由于Z-型膜中没有花生酸或花生酸镉的屏蔽,分子间具有较强的偶极相互作用,加热使聚集体的离解的程度较小.镉离子的加入对半花菁LB多层膜的稳态荧光谱也有一定的影响. 相似文献
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本文利用不同波段的时间分辨荧光和三维荧光谱对半花菁分子激发态的动力学特性进行了研究。在半花菁/花生酸交替的Y型多层膜中,半花菁分子形成的H-聚集体引起其三维荧光谱蓝移,并且荧光峰随时间的变化逐渐向红光方向移动。由于聚集体内所有分子间的相互作用(耦合)相干叠加,使得LB膜中的半花菁分子的激发态寿命比溶液寿命要短,由激发态较高振动能级向低能级过渡较快,因而不同波段的起始发光时间相差也较小。 相似文献
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LB膜的制膜条件优化及其对光学性能的影响 总被引:1,自引:1,他引:0
通过紫外-可见吸收光谱、二次谐波振荡和稳态荧光的测量,研究了半花菁(DAEP)Langmuir-Blodgett(LB)膜在不同制膜条件(压膜速度、半花菁和花生酸混合、亚相中加入碘离子)下,LB膜样品中半花菁分子的聚集体性质的改变和对非线性光学性能的影响.实验发现,纯半花菁LB膜中分子形成H-聚集体,从而导致吸收峰、荧光峰的蓝移和分子二阶非线性极化率β的减少.分子聚集程度的减少和分子二阶非线性系数β的增加可以通过增大压膜速度、半花菁和花生酸混合、亚相中加入碘离子等方法实现. 相似文献
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用光学线性和非线性方法研究了Y型半花菁/花生酸交替LB多层膜的光致光学各向异性。在纳秒紫外偏振脉冲激光照射下,LB多层膜中半花菁分子发色团长轴向紫外光偏振方向重新取向。加热可以使LB多层膜平面内各向异性消失及H-聚集体分解。 相似文献
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采用射频磁控溅射技术在Pt/Ti/SiO2/Si(100)衬底上生长了掺镧钛酸铅(PLT)铁电薄膜.用X射线衍射技术(XRD)研究了PLT薄膜结晶性能,结果表明PLT薄膜为 (111)择优取向钙钛矿相织构.使用原子力显微镜(AFM)和压电响应力显微镜(PFM) 分别观察了PLT薄膜的表面形貌和对应区域的电畴结构.PFM观察显示PLT薄膜中存在90°纳米带状畴,电畴的极化为首尾相接的低能量的排列方式,带状畴的宽度为20—60nm.研究了PLT10铁电薄膜的制备条件与性能之间的关系.发现在优化条件下制备的PLT10铁电薄膜的介电常数εr为365、介电损耗tgδ为0.02,热释电系数γ为2.18×10-8C·(cm2·K)-1,可以满足制备非制冷红外探测器的需要.
关键词:
PLT薄膜
电畴
PFM
极化 相似文献
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Sol-gel-derived pyroelectric barium strontium titanate thin films for infrared detector applications 总被引:3,自引:0,他引:3
J.-G. Cheng J. Tang A.-J. Zhang X.-J. Meng J.-H. Chu 《Applied Physics A: Materials Science & Processing》2000,71(6):667-670
Quality pyroelectric Ba0.8Sr0.2TiO3 films have been successfully fabricated by a sol-gel processing using a highly diluted precursor solution. The remnant polarization
of the films decreases with the temperature increasing, which results in a large pyroelectric coefficient at room temperature.
Infrared response measured using a 500-K chopped blackbody at room temperature exhibits a typical pyroelectric response waveform.
Frequency dependence of the infrared response measurement for a pixel with area of 2.5×10-3 cm2 showed that the maximum response output voltage of 3.2 mV was obtained at 6 Hz. Better infrared response can be expected
by the improvement in thermal isolation of the pixels and electrode materials.
Received: 26 April 2000 / Accepted: 9 May 2000 / Published online: 9 August 2000 相似文献
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Cong Chen Tingyin Ning Heng Lu Can Wang Dongxiang Zhang Pei Wang Hai Ming Yueliang Zhou Guozhen Yang 《Applied Physics A: Materials Science & Processing》2010,99(4):849-852
A pyroelectric behavior was observed in CaCu3Ti4O12 films and the pyroelectric coefficient was measured to be 1.35×10?7 C/cm2?K for a film with thickness of 700 nm from 295 K to 340 K, larger than those of most pyroelectric materials. It was observed that the pyroelectric coefficient increased with the thickness of films from 300 to 700 nm. The origin of pyroelectric effect is proposed to depend on the distortion of the Ti–O octahedron due to the presence of Ti3+ ions. Comparing with the measurement result of an unpolarized film, our study strongly supports the interpretation of relaxor ferroelectric behavior in CaCu3Ti4O12. 相似文献
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用PECVD薄膜沉积方法,成功地制备了磷掺杂纳米硅(nc-Si:H(P))薄膜.用扫描隧道电镜(STM)、Raman散射、傅里叶变换红外吸收(FTIR)谱、电子自旋共振(ESR)、共振核反应(RNR)技术对掺磷纳米硅进行了结构分析,确认了样品的微结构为纳米相结构.掺磷后膜中纳米晶粒的平均尺寸d减小,一般在25—45nm之间,且排列更加有序.掺磷nc-Si:H膜具有较高的光吸收系数,光学带隙在173—178eV之间,和本征nc-Si:H相同.掺杂nc-Si:H薄膜电导率在10-1关键词: 相似文献
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W. Künstler M. Wegener M. Seiß R. Gerhard-Multhaupt 《Applied Physics A: Materials Science & Processing》2001,73(5):641-645
Films of poly(vinylidene fluoride-hexafluoropropylene) copolymer [P(VDF-HFP)] were cast from a dimethylsulfoxide (DMSO)/acetone
solution of Solef?85-15 P(VDF-HFP) copolymer powder grade 21508. Undrawn and uniaxially drawn cast copolymer films were investigated
with respect to their piezo- and pyroelectric properties. Quasistatic charge integration was employed for the determination
of the poling-field dependence of the piezoelectric d31 and pyroelectric p3 coefficients. In addition, the thermal stability of the pyroelectric effect was studied with a combination of thermally stimulated
discharge (TSD) and temperature-modulation techniques. Cast copolymer films could withstand electrical poling fields of up
to 400 MV/m. The maximum values of d31=30 pC/N and p3=49 μC/(m2K) for uniaxially drawn samples are similar to those found on commercial PVDF films and much higher than those on pure PVDF
films cast from solution. Samples kept for 5 min at 150 °C still exhibit 30–40% of the initial pyroelectric effect [up to
around 20 μC/(m2K)]. After this annealing step, no further decay of the pyroelectric coefficient could be observed during storage at 120 °C
for several hours.
Received: 5 July 2001 / Accepted: 27 July 2001 / Published online: 2 October 2001 相似文献
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The effects of TiOx diffusion barrier layer thickness on the microstructure and pyroelectric characteristics of PZT thick films were studied in this paper. The TiOx layer was prepared by thermal oxidation of Ti thin film in air and the PZT thick films were fabricated by electrophoresis deposition method (EPD). To demonstrate the barrier effect of TiOx layer, the electrode/substrate interface and Si content in PZT thick films were characterized by scanning electron microscope (SEM) and X-ray energy dispersive spectroscopy (EDS), respectively. The TiOx barrier thickness shows significant influence on the bottom electrode and the pyroelectric performance of the PZT thick films. The average pyroelectric coefficient of PZT films deposited on 400 nm TiOx layer was about 8.94 × 10−9 C/(cm2 K), which was improved by 70% than those without diffusion barrier layer. The results showed in this study indicate that TiOx barrier layer has great potential in fabrication of PZT pyroelectric device. 相似文献
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本文用一维热扩散模型推出了体吸收、悬空型、边电极热电探测器响应率的表达式,并计算了SBN热电探测器的响应率和NEP与材料的吸收系数、器件厚度、工作频率以及前置放大器输入电容之间的关系。本文认为:1.体吸收、悬空型、边电极热电探测器具有最佳响应率厚度和最佳NEP厚度。两种最佳厚度可以根据本文导出的响应率公式和已知的噪声公式计算出来。2.在某些波段,如果能把材料的吸收系数提高到5×104cm-1以上,就可以研制性能优良的体吸收薄膜器件。 相似文献
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STUDY ON PREPARATION OF UV CROSS-LINKING FILMS OF POLYURETHANE-LiClO4 COMPLEXES AND THEIR IONIC CONDUCTIVITY 下载免费PDF全文
The complexes of polyurethane containing double bonds with LiClO4 were formed, and cross-linked films were produced by UV radiation, All of the films were uniform, transparent, flexible and smooth-faced with a considerable mechanical strength. The ionic conductivities of the films of several series of polymers with different molecule weights of PEG segment were measured, of which the highest is 8.09×10-5S·cm-1 at 300K under anhydrous atmosphere. Also the conductivity is deeply influenced by the molecule weight of the soft segment PEG of the polyurethane and the content of LiClO4. The transport number of Li+ is about 0.57. Structure characteristic measurement much as DSC, XRD, IR etc., have been done and the conductive mechanism is discussed. 相似文献