Preparation,Characterization and Photothermal Study of PVA/Ti_(2)O_(3) Composite Films

In this work,flexible photothermal PVA/Ti_(2)O_(3) composite films with different amount(0 wt%,5 wt%,10 wt%,15 wt%)of Ti_(2)O_(3) particles modified by steric acid were prepared by a simple solution casting method.The microstructures,XRD patterns,FTIR spectra,UV-Vis-NIR spectra thermo-conductivity,thermo-stability and photothermal effects of these composite films were all characterized.These results indicated that Ti_(2)O_(3) particles were well dispersed throughout the polyvinyl alcohol(PVA)matrix in the PVA/Ti_(2)O_(3) composite films.And Ti_(2)O_(3) particles could also effectively improve the photothermal properties of the composite films which exhibited high light absorption and generated a high temperature(about 57.4℃for film with 15 wt%Ti_(2)O_(3) amount)on the surface when it was irradiated by a simulated sunlight source(1 kW/m^(2)).

Enhanced Electrical Properties of Bi_(2−x)Sb_(x)Te_(3) Nanoflake Thin Films Through Interface Engineering

The structure–property relationship at interfaces is difficult to probe for thermoelectric materials with a complex interfacial microstructure.Designing thermoelectric materials with a simple,structurally-uniform interface provides a facile way to understand how these interfaces influence the transport properties.Here,we synthesized Bi_(2−x)Sb_(x)Te_(3)(x=0,0.1,0.2,0.4)nanoflakes using a hydrothermal method,and prepared Bi_(2−x)Sb_(x)Te_(3) thin films with predominantly(0001)interfaces by stacking the nanoflakes through spin coating.The influence of the annealing temperature and Sb content on the(0001)interface structure was systematically investigated at atomic scale using aberration-corrected scanning transmission electron microscopy.Annealing and Sb doping facilitate atom diffusion and migration between adjacent nanoflakes along the(0001)interface.As such it enhances interfacial connectivity and improves the electrical transport properties.Interfac reactions create new interfaces that increase the scattering and the Seebeck coefficient.Due to the simultaneous optimization of electrical conductivity and Seebeck coefficient,the maximum power factor of the Bi_(1.8)Sb_(0.2)Te_(3) nanoflake films reaches 1.72 mW m^(−1)K^(−2),which is 43%higher than that of a pure Bi_(2)Te_(3) thin film.

Optimal parameter space for stabilizing the ferroelectric phase of Hf_(0.5)Zr_(0.5)O_(2) thin films under strain and electric fields

Hafnia-based ferroelectric materials, like Hf_(0.5)Zr_(0.5)O_(2)(HZO), have received tremendous attention owing to their potentials for building ultra-thin ferroelectric devices. The orthorhombic(O)-phase of HZO is ferroelectric but metastable in its bulk form under ambient conditions, which poses a considerable challenge to maintaining the operation performance of HZO-based ferroelectric devices. Here, we theoretically addressed this issue that provides parameter spaces for stabilizing the O-phase of HZO thin-films under various conditions. Three mechanisms were found to be capable of lowering the relative energy of the O-phase, namely, more significant surface-bulk portion of(111) surfaces, compressive c-axis strain,and positive electric fields. Considering these mechanisms, we plotted two ternary phase diagrams for HZO thin-films where the strain was applied along the in-plane uniaxial and biaxial, respectively. These diagrams indicate the O-phase could be stabilized by solely shrinking the film-thickness below 12.26 nm, ascribed to its lower surface energies. All these results shed considerable light on designing more robust and higher-performance ferroelectric devices.

Numerical Analysis on the Effect of n-Si on Cu(In, Ga)Se2 Based Thin-Films for High-Performance Solar Cells by 1D-SCAPS

We report the performances of a chalcopyrite Cu(In, Ga)Se2 CIGS-based thin-film solar cell with a newly employed high conductive n-Si layer. The data analysis was performed with the help of the 1D-Solar Cell Capacitance Simulator (1D-SCAPS) software program. The new device structure is based on the CIGS layer as the absorber layer, n-Si as the high conductive layer, i-In2S3, and i-ZnO as the buffer and window layers, respectively. The optimum CIGS bandgap was determined first and used to simulate and analyze the cell performance throughout the experiment. This analysis revealed that the absorber layer’s optimum bandgap value has to be 1.4 eV to achieve maximum efficiency of 22.57%. Subsequently, output solar cell parameters were analyzed as a function of CIGS layer thickness, defect density, and the operating temperature with an optimized n-Si layer. The newly modeled device has a p-CIGS/n-Si/In2S3/Al-ZnO structure. The main objective was to improve the overall cell performance while optimizing the thickness of absorber layers, defect density, bandgap, and operating temperature with the newly employed optimized n-Si layer. The increase of absorber layer thickness from 0.2 - 2 µm showed an upward trend in the cell’s performance, while the increase of defect density and operating temperature showed a downward trend in solar cell performance. This study illustrates that the proposed cell structure shows higher cell performances and can be fabricated on the lab-scale and industrial levels.

钙钛矿太阳电池的界面钝化膜构建及钝化效果监测策略

该文针对经典n-i-p结构的钙钛矿太阳电池中突出的TiO_(2)/钙钛矿界面紫外不稳定问题,分析一步溶液法制备钝化膜的研究现状,并指出一步溶液法制备的钝化膜普遍存在太薄且裸漏的问题。最后,提出以廉价且全紫外光谱有效的无机盐屏障CsBr全面钝化TiO_(2)的研究策略,即通过超快结晶过程制备极薄且全覆盖的CsBr薄膜,形成微观尺度无机盐薄膜微结构调控的方法,此外,提出应用慢正电子湮没技术,定位监测钝化后钙钛矿的服役退化进程策略,这些对于实现TiO_(2)/钙钛矿界面的紫外稳定化,具有理论和实践的双重指导价值。

Si基片上射频磁控溅射MgF_2薄膜的光学常数研究

用射频磁控溅射技术在室温Si基片上制备了厚度分别为25.0nm和60.7nm的MgF2薄膜样品,并用反射式椭偏光谱技术对薄膜的光学常数进行了测试分析。250～830nm光频范围椭偏光谱测量结果表明:随着膜厚增加,MgF2薄膜的光学常数n、k的变化范围减小,平均值增大;MgF2薄膜样品的吸收曲线k在波长λ为270nm和360nm处均出现由通过辐射产生的F心引起的吸收峰。

在Si基底上真空蒸发沉积Ag-MgF_2复合薄膜的内应力研究

报道了用电子薄膜应力分布测试仪测量了不同温度、不同厚度的Ag MgF2复合薄膜的内应力变化情况,得到了基底温度(退火温度)在300～400℃范围内薄膜平均应力最小,且处于张应力向压应力转变区域。XRD分析表明,在Ag MgF2复合薄膜中Ag对复合薄膜内应力的影响大于MgF2。

Ag-MgF_2金属陶瓷薄膜的制备及其微观结构研究

用真空双蒸发源交替蒸发法和单蒸发源混合瞬时蒸发法制备了Ag-MgF2金属陶瓷薄膜。透射电镜、电子衍射、X射线衍射以及X射线光电子能谱分析结果表明，薄膜由晶态超微粒Ag镶嵌于主要为非晶态的MgF2中构成。Ag-MgF2形成的金属陶瓷复合晶体结构所对应的主要谱峰为d=0．26102，0．23540，0．20393nm。用真空单蒸发源混合瞬时蒸发法制备的Ag-MgF2薄膜表面元素的结合能大于双蒸发源交替蒸发法制备的薄膜表面元素的结合能。

Improvement of adhesion properties of TiB_2 films on 316L stainless steel by Ti interlayer films

The periodic [Ti/TiB2]n （n=l, 2, 3） multilayered films were prepared on the substrate of AISI 316L stainless steel by magnetron sputtering to enhance the adhesion of TiB2 films based on the remarkable mechanical performance of layered films. The influence of periods on microstructure, adhesion and hardness of [Ti/TiB2]n multilayered films was studied. X-ray diffraction （XRD） analysis shows that the monolayer TiB2 films exhibit （001） preferred orientation, and the preferred orientation of [Ti/TiB2], multilayered films transfers from （001） to （100） with the increase of periods. The cross-sectional morphology of each film displays homogeneity by field emission scanning electron microscopy （FESEM）. The hardness of the films measured via nanoindention changes from 20 to 26 GPa with the increase of periods. These values of hardness are a bit lower than that of the monolayer TiB2 films which is up to 33 GPa. However, the [Ti/TiB2]n multilayered films present a considerably good adhesion, which reaches a maximum of 24 N, in comparison with the monolayer TiB2 films according to the experimental results.

Preparation and characterization of ZrO_2/TiO_2 composite photocatalytic film by micro-arc oxidation

ZrO2/TiO2 composite photocatalytic film was produced on the pure titanium substrate using in-situ Zr（OH）4 colloidal particle by the micro-arc oxidation technique and characterized by scanning electron microscope （SEM）, energy dispersive X-ray （EDX）, X-ray diffraction （XRD） and ultraviolet-visible （UV-Vis） spectrophotometer. The composite film shows a lamellar and porous structure which consists of anatase, futile and ZrO2 phases. The optical absorption edge of film is shifted to longer wavelength when ZrO2 is introduced to TiO2. Furthermore, the photocatalytic reaction rate constants of degradation of rhodamine B solution with ZrO2/TiO2 composite film and pure TiO2 film under ultraviolet irradiation are measured as 0.0442 and 0.0186 h 1, respectively.

Al-MgF_2金属陶瓷薄膜的微观结构与光学特性

本文首次报道了用真空蒸发制备的Ａｌ－ＭｇＦ２ 金属陶瓷薄膜微观结构与光学特性。在２００～８００ｎｍ 波段，薄膜的反射率很低，为１％ ～２．５％ ；透射率则呈抛物线上升，至８００ｎｍ处达７２％ ；吸光度随波长增大呈指数下降。Ａｌ－ＭｇＦ２ 金属陶瓷薄膜的这种光学性质与其微观结构有关。文章还对Ａｌ－ＭｇＦ２ 金属陶瓷薄膜的制备技术和氧化现象进行了讨论。

Photoelectrocatalytic reduction of CO_2 into formic acid using WO_(3-x)/TiO_2 film as novel photoanode

A novel WO3-x/TiO2 film as photoanode was synthesized for photoelectrocatalytic（PEC） reduction of CO2 into formic acid（HCOOH）. The films prepared by doctor blade method were characterized with X-ray diffractometer（XRD）, scanning electron microscope（SEM） and transmission electron microscope（TEM）. The existence of oxygen vacancies in the WO3-x was confirmed with an X-ray photoelectron spectroscopy（XPS）, and the accurate oxygen index was determined by a modified potentiometric titrimetry method. After 3h of photoelectrocatalytic reduction, the formic acid yield of the WO3-x/TiO2 film is 872 nmol/cm^2, which is 1.83 times that of the WO3/TiO2 film. The results of PEC performance demonstrate that the introduction of WO3-x nanoparticles can improve the charge transfer performance so as to enhance the performance of PEC reduction of CO2 into formic acid.

Effect of Zn and Ti mole ratio on microstructure and photocatalytic properties of magnetron sputtered TiO_2-ZnO heterogeneous composite film

Series of TiO 2-ZnO heterojunction composite films with different n（Zn）/n（Ti） ratios were prepared by UDP450 magnetron sputter ion plating equipment, and the mole ratio of Zn to Ti was controlled by adjusting the current values of sputtering target. The effects of n（Zn）/n（Ti） on the microstructures of TiO2-ZnO films were investigated by SEM, AFM, Raman and XPS, and their photocatalytic decomposition of methyl orange solutions was evaluated. The results show that an increase in n（Zn）/n（Ti） typically results in a decrease in the grain size of composite films firstly and then an increase of grain size, while an increase in n（Zn）/n（Ti） leads to an increase in film roughness firstly and then a decrease in film roughness. Both grain size and roughness of TiO2-ZnO films reach the maximum and minimum at n（Zn）/n（Ti） of 1/9.3, respectively. The n（Zn）/n（Ti） shows little effect on the valences of Zn and Ti elements, which mainly exist in the form of TiO2 and ZnO phases. The n（Zn）/n（Ti） has influence on the amount of anatase/rutile TiO2 heterojunction in the film. With increase of the n（Zn）/n（Ti）, the absorption intensity of the composite film increases and the absorption region extends to 450 nm, which is redshifted as much as 150 nm in comparison with the pure TiO2 films. However, the photocatalytic abilities of heterogeneous composite films do not depend on the n（Zn）/n（Ti） but rather on the microstructures of the TiO2-ZnO composite films. Degradation rate of the film reaches the maximum and the photocatalytic decomposition of pollutants works best when n（Zn）/n（Ti）=1：9.3.

类金刚石薄膜作为MgF_2红外增透和保护膜的研究

系统地研究了MgF2衬底上类金刚石薄膜的折射率和生长速率与淀积工艺之间的关系，在MgF2衬底上成功地设计并制备了红外增透和保护膜。理论与实验研究表明，类金刚石薄膜使MgF2的红外透过率提高3％以上是完全可能的，但起红外增透和保护双重作用的统一性问题仍有待进一步研究。

Au-MgF_2复合纳米颗粒薄膜的制备和微结构

用射频磁控共溅射法制备了Au体积分数分别为 6 %、1 5 %、2 5 %、4 0 %、5 0 %和 6 0 %的Au MgF2 复合纳米颗粒薄膜。用X射线衍射、透射电镜、X射线光电子能谱对薄膜的微结构和组分进行了测试分析 ,分析结果表明 :制备的Au MgF2 复合纳米颗粒薄膜由fcc Au晶态纳米微粒镶嵌于主要为非晶态的MgF2 陶瓷基体中构成 ,当Au体积百分含量由 1 5 %增至 6 0 %时 ,其平均晶粒尺寸由 5 1nm增大到 2 1 2nm ,晶格常数由 0 39984nm增大到 0 4 0 74 3nm ;随Au体积百分含量由 6 %增至5 0 % ,其颗粒平均粒径则由 9 8nm增至 2 1 4nm。名义组分为vol.6 0 %Au MgF2 样品中Au的体积百分含量约为 6 2 6 % ,与设计值基本一致。

Ag-MgF_2纳米金属陶瓷薄膜的光吸收特性

测量了真空热蒸发沉积法制备的Ag MgF2 纳米金属陶瓷薄膜在近紫外到可见光区的吸收光谱、光学常数和介电函数 ,观察到在 42 7nm处有明显的表面等离子激元共振吸收峰。消光系数与介电函数的虚部谱形类似。

退火温度对Ag-MgF_2颗粒膜结构和内应力的影响

报道用电子薄膜应力分布测试仪测量退火温度对Ag -MgF2 复合颗粒薄膜内应力的影响 ,结果表明 ,退火温度在 40 0℃ ,薄膜平均应力最小 ,应力分布比较均匀。XRD分析表明 ,Ag -MgF2 复合颗粒薄膜的内应力主要来自Ag晶粒的生长过程 ,当Ag的晶格常数接近块体时 (40 0℃温度退火 6 0分钟 ) ,Ag-MgF2 薄膜内应力最小。

Cu-MgF_2纳米金属陶瓷薄膜的微结构及吸收光谱特性研究

对用蒸发技术制备的Cu -MgF2 纳米金属陶瓷薄膜微结构及吸收光谱特性进行了研究。微结构分析表明薄膜由fcc -Cu纳米晶粒镶嵌于主要呈非晶态的MgF2 基体中所组成 ,晶粒的平均粒度约为 1 4～ 1 6nm。Cu -MgF2 纳米金属陶瓷薄膜在 2 0 0～ 80 0nm波段内的吸收光谱表明 :随着波长增加 ,吸收减小 ;Cu纳米晶粒的表面等离子共振吸收峰出现于 560nm处 ;短波长区呈现较强的Cu的带间跃迁吸收。用三维弥散系统的Maxwell-Garnett理论对Cu -MgF2 复合体系的实验吸收光谱特性作出了解释。

Ag-MgF_2复合金属陶瓷薄膜的结构与光学特性研究

以真空烧结的Ag-MgF2粉体为蒸发材料,用真空蒸镀法制备了Ag-MgF2金属陶瓷薄膜,X射线衍射、红外以及紫外-可见光谱研究表明:薄膜为由纳米fcc-Ag晶粒镶嵌于主要为非晶态的MgF2基体中构成。在400～1600cm-1波数范围,Ag-MgF2金属陶瓷薄膜具有400～600cm-1的MgF2晶体特征吸收带和Ag-MgF2复合结构产生的730～1250cm-1的吸收谱带;在200～800nm波长范围,Ag-MgF2金属陶瓷薄膜对波长为220～800nm的光波均具有很低的反射率和很强的吸收,对波长为340～580nm的光波吸收率高达85%以上;而在紫外光区,Ag-MgF2薄膜则具有高反射率(>51%)

有效介质理论在Ag-MgF_2复合纳米颗粒薄膜中的应用

将描述弥散体系行为的Maxwell Garnett理论与Bruggeman理论应用于Ag MgF2 复合纳米颗粒薄膜 ,分别计算出该复合体系在 2 5 0nm～ 830nm波段范围内的光学常数n、k随波长λ的变化 ,并与实验结果进行比较。发现较之普遍采用的Maxwell Garnett理论 ,由Bruggeman理论计算出的n λ、k λ曲线的峰位、峰宽及峰位随Ag组分质量百分率的位移都与实验结果更为接近。