高性能智能窗用掺钨二氧化钒膜系的研制

针对智能窗用的二氧化钒膜系需相变温度接近室温、红外调节率高、可见光透过率高等实际问题,通过薄膜设计(Coating designer,CODE)软件设计了一种由掺钨(Tungsten-doped,W-doped)二氧化钒(Vanadium dioxide,VO2)层和二氧化硅(Silicon dioxide,SiO2)减反层组成的高性能智能窗膜系。系统研究了各层膜的厚度对红外调节率和可见光透过率的影响,确定综合性能优良的膜系为玻璃/70nm掺钨二氧化钒/50nm二氧化硅,并采用大面积多靶磁控溅射系统制备出了该膜系。实验测得膜系的相变温度为38.2℃,红外调节率(2400 nm波长处)为40.4%,可见光的峰值透过率为46.3%。在太阳能红外波段,膜系具有良好的入射调节效果。此外,该膜系的制备方法与现有的大面积镀膜玻璃工艺兼容,适于工业化生产。     

二氧化钒薄膜制备及其热致变发射率特性研究

通过溶胶-凝胶和真空热处理工艺在石英基底上制备了二氧化钒薄膜,对制备出的薄膜进行了X射线衍射及X射线光电子能谱分析,结果表明所制备出的薄膜价态单一,纯度较高,薄膜为多晶态,晶粒尺寸约为27 nm.利用红外热像仪拍摄了薄膜在不同温度下的红外热图并计算了发射率,结果表明二氧化钒薄膜7.5～14 μm波段发射率在相变时发生突变,突变量可达0.6,具有优异的热致变发射率性能,在红外自适应伪装等领域应用前景广阔.     

二氧化钒在红外自适应隐身技术中的应用

二氧化钒(VO2)是一种热致可逆相变氧化物,在约68℃时发生由半导体态向金属态的一级位移型相变,同时伴随着显著的电学、磁学、光学特性的变化,且相变温度可通过掺杂调节。制备了二氧化钒粉体和薄膜材料,分别研究了两种材料的热致红外发射率变化特性;采用热像仪拍摄了二氧化钒涂层和薄膜不同温度的红外热图,探讨了其在隐身技术中的应用。结果表明:二氧化钒涂层和薄膜在相变前后具有主动控制自身辐射强度的特性,在红外自适应隐身技术中具有一定的应用前景。     

VO_2热色智能玻璃研究进展

二氧化钒(VO2)是一种受人关注的热致变色材料,在68℃时发生从半导体相-金属相的转变,且相变可逆。在介绍智能玻璃在建筑节能中潜在应用的基础上,重点阐述了VO2纳米薄膜应用于智能型节能玻璃的国内外研究进展。较全面地论述了利用光学减反射技术提高VO2智能玻璃可见光透过率的技术现状。总结了VO2智能玻璃在实际应用中存在的技术难点:节能效率偏低、薄膜沉积温度高、外观颜色不美观、保温性能上的缺陷等。展望了VO2智能玻璃的研究与应用前景。     

二氧化钒多晶薄膜的掺杂改性

掺杂能明显改变二氧化钒薄膜的相变温度,影响其电学和光学性质。研究表明：W、Mo等大尺寸原子掺杂可以有效降低相变温度,而Al、P等小尺寸原子掺杂则使相变温度升高。综述、比较了不同掺杂方法和掺杂元素对相变、相变滞豫、电阻和透射性能的影响,介绍了用离子束增强沉积方法对二氧化钒薄膜掺杂改性的优点。综合分析表明,通过对二氧化钒多晶薄膜的掺杂改性,将相变温度降至室温附近,可以大大提高薄膜的室温电阻温度系数。     

钽掺杂对二氧化钒多晶薄膜相变特性的影响

将Ta_2O_5与V_2O_5均匀混合,压制成溅射靶,用离子束增强沉积方法在二氧化硅衬底上沉积掺Ta氧化钒薄膜.在氮气中适当退火,形成掺杂二氧化钒多晶薄膜.X射线衍射结果显示,薄膜具有单一的(002)取向.XPS测试表明,膜中V为+4价,Ta以替位方式存在.温度-电阻率测试表明,薄膜具有明显的相变行为,原子比为3%的Ta掺杂后,二氧化钒多晶薄膜相变温度降低到约48℃.Ta原子的半径大于V原子的半径,Ta的掺入在薄膜中引入了张应力;5价Ta 替代4价V,在d轨道中引入多余电子,产生施主能级,这些是掺钽二氧化钒多晶薄膜相变温度降低的原因.     

二氧化钒薄膜的制备及性能表征

通过激光脉冲沉积法,分别在Csapphire和R—sapphire衬底上制备了单相二氧化钒（VO2）薄膜。用x射线衍射法表征了不同实验条件下制备的二氧化钒薄膜的结构性质,分析表明在600℃,10^-2torr的氧气分压下,生长15min可得到单相的二氧化钒（VO2）薄膜;重点研究了激光能量对薄膜电学性质的影响,实验结果表明激光能量在500-600MJ对制备的二氧化钒薄膜具有最好的电学性质。     

隧道穿透对Sol-gel多晶二氧化钒薄膜电阻率的影响模拟

在多晶薄膜晶粒一晶界两相结构模型的基础上,考虑载流子对晶粒间界势垒区的隧穿机制,在10℃-100℃的温度范围内,模拟了Sol-gel多晶二氧化钒薄膜电阻率随温度的变化,模拟结果与实验结果有较好的吻合．模拟结果显示,二氧化钒多晶薄膜的晶界效应限制了薄膜相变时电阻率的变化,并使薄膜在金属相时呈现负的温度系数．     

二氧化钒薄膜的反常热色性能和热滞回线

利用磁控溅射技术在玻璃衬底上制备了不同厚度的二氧化钒(VO2)薄膜.实验结果表明,所制备的VO2薄膜都具有显著的热色性能.厚度较大的薄膜在低温时具有较高的透过率,而在高温时具有较低的透过率.然而,厚度较小的薄膜在500～860 nm波长内的情况正好相反,即低温透过率比高温时的小.厚度较小的薄膜在500～860 nm波长内具有沿逆时针方向的热滞回线,这恰好与波长大于860 nm的情况相反.利用光学干涉理论对这一反常的热色现象及热滞回线进行了理论解释,为进一步理解VO2薄膜的热色性能及相变性能提供参考.     

基于二氧化钒相变材料的光电器件激光防护研究

随着激光致盲武器的快速发展，与之对应的激光致盲防护技术逐渐成为了一项重要的研究。相变材料二氧化钒(VO₂)因在合适的热、光、场等激励下发生半导体相与金属相的可逆相变导致光学和电学特性的显著变化而受到激光防护领域的持续关注。使用Drude-Lorentz模型对VO₂的光学常数进行了研究，针对单层二氧化钒在半导体相红外透过率不够高的问题进行了多层膜设计和优化，并实际制作了多层膜系。使用激光器与傅里叶红外光谱仪测试制备的VO₂薄膜，得到了薄膜的相变与防护效果等性能，验证了VO₂良好的激光致盲防护性能，实际测试表明半导体相的透过率大于92%，相变前后多层膜系的红外开关率超过98%。     

薄膜太阳能电池的研究进展

薄膜太阳能电池是缓解能源危机的新型光伏器件。评述了薄膜太阳能电池的优缺点,主要介绍了薄膜硅太阳能电池、多元化合物薄膜太阳能电池和有机薄膜太阳能电池的研究现状,总结了它们各自在价格成本、光电转换效率及对环境影响等方面的特点,并对其发展趋势进行了展望。     

激光法制备二氧化钒军事防护薄膜研究

二氧化钒(VO2)具有热致半导体—金属相变特性, 其相变温度为 68益, 最接近室温, 可作为理想的光学功能材料, 在军事上有广泛应用前景。脉冲激光沉积法作为一种新型的制膜方法, 相比其他方法具有粒子能量高、可控性强等优点。介绍了 VO2薄膜的光电特性及其在军事上尤其是激光防护领域的应用前景, 并重点探讨了激光法制备 VO2薄膜的相关问题及解决措施。     

基于二氧化钒薄膜的太赫兹开关器件

二氧化钒(VO2)作为一种优质的光电功能材料一直备受人们的关注,在信息存储、光调制器、太阳能电池、光电探测器等方面有着重要应用。采用磁控溅射及原位退火氧化的"两步法"制备了VO2薄膜,并对其进行晶态、形貌表征。设计并搭建VO2薄膜热致相变实验系统,研究了VO2薄膜在变温条件下对2.52 THz辐射的开关特性。结果表明,VO2薄膜样品为多晶态,具有明显的太赫兹调制效果,可以实现对2.52 THz波的调制,并可作为太赫兹开关/调制器件的功能材料。     

ZnSe/ITO thin films:candidate for CdTe solar cell window layer

The crystal structure, electrical and optical properties of ZnSe thin films deposited on an In₂O₃:Sn (ITO) substrate are evaluated for their suitability as the window layer of CdTe thin film solar cells. ZnSe thin films of 80, 90, and 100 nm thickness were deposited by a physical vapor deposition method on Indium tin oxide coated glass substrates. The lattice parameters are increased to 5.834 Å when the film thickness was 100 nm, which is close to that of CdS. The crystallite size is decreased with the increase of film thickness. The optical transmission analysis shows that the energy gap for the sample with the highest thickness has also increased and is very close to 2.7 eV. The photo decay is also studied as a function of ZnSe film thickness.     

薄膜太阳电池技术发展趋势浅析

低成本、高效率的薄膜太阳电池是未来光伏产业发展的重要方向之一。主要介绍了目前备受关注的薄膜太阳电池,包括硅基薄膜太阳电池、铜铟镓硒与铜锌锡硫薄膜太阳电池,及砷化镓薄膜太阳电池等,简述了它们的各自特点、研究现状、主要技术路线和产业化发展等情况。最后展望了薄膜太阳电池未来的发展趋势。     

Theoretical simulation of performances in CIGS thin-film solar cells with cadmium-free buffer layer

Copper indium gallium selenium (CIGS) thin film solar cells have become one of the hottest topics in solar energy due to their high photoelectric transformation efficiency. To real applications, CIGS thin film is covered by the buffer layer and absorption layer. Traditionally, cadmium sulfide (CdS) is inserted into the middle of the window layer (ZnO) and absorption layer (CIGS) as a buffer layer. However, the application of the GIGS/CdS thin film solar cells has been limited because of the environmental pollution resulting from the toxic cadmium atom. Although zinc sulfide (ZnS) has been proposed to be one of the candidates, the performance of such battery cells has not been investigated. Here, in this paper, we systematically study the possibility of using zinc sulfide (ZnS) as a buffer layer. By including the effects of thickness, concentration of a buffer layer, intrinsic layer and the absorbing layer, we find that photoelectric transformation efficiency of ZnO/ZnS(n)/CIGS(i)/CIGS(p) solar cell is about 17.22%, which is qualified as a commercial solar cell. Moreover, we also find that the open-circuit voltage is~0.60 V, the short-circuit current is~36.99 mA/cm² and the filled factor is~77.44%. Therefore, our results suggest that zinc sulfide may be the potential candidate of CdS as a buffer layer.     

Improvement of the cell performance in the ZnS/Cu(In,Ga)Se2 solar cells by the sputter deposition of a bilayer ZnO : Al film

ZnS is a candidate to replace CdS as the buffer layer in Cu(In,Ga)Se₂ (CIGS) solar cells for Cd‐free commercial product. However, the resistance of ZnS is too large, and the photoconductivity is too small. Therefore, the thickness of the ZnS should be as thin as possible. However, a CIGS solar cell with a very thin ZnS buffer layer is vulnerable to the sputtering power of the ZnO : Al window layer deposition because of plasma damage. To improve the efficiency of CIGS solar cells with a chemical‐bath‐deposited ZnS buffer layer, the effect of the plasma damage by the sputter deposition of the ZnO : Al window layer should be understood. We have found that the efficiency of a CIGS solar cell consistently decreases with an increase in the sputtering power for the ZnO : Al window layer deposition onto the ZnS buffer layer because of plasma damage. To protect the ZnS/CIGS interface, a bilayer ZnO : Al film was developed. It consists of a 50‐nm‐thick ZnO : Al plasma protection layer deposited at a sputtering power of 50 W and a 100‐nm‐thick ZnO : Al conducting layer deposited at a sputtering power of 200 W. The introduction of a 50‐nm‐thick ZnO : Al layer deposited at 50 W prevented plasma damage by sputtering, resulting in a high open‐circuit voltage, a large fill factor, and shunt resistance. The ZnS/CIGS solar cell with the bilayer ZnO : Al film yielded a cell efficiency of 14.68%. Therefore, the application of bilayer ZnO : Al film to the window layer is suitable for CIGS solar cells with a ZnS buffer layer. Copyright © 2012 John Wiley & Sons, Ltd.     

基于VO2/TiO2/FTO微结构的电压诱导相变存储器特性

相变存储器作为下一代具有竞争力的新型存储器,其基础和核心是相变存储介质.为了制备基于VO2薄膜的非易失性相变存储器,首先采用等离子体增强化学气相沉积法在氟掺杂二氧化锡(FTO)导电玻璃衬底上沉积一层厚度为100 nm的TiO2薄膜,再通过直流磁控溅射法制备VO2薄膜,并在TiOJFTO复合薄膜上形成VO2/TiO2/FTO微结构,用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、四探针测试仪和半导体参数测试仪表征分析微结构的结晶和非易失性相变存储特性.结果表明,N2和O2的体积流量比为60∶40时,在TiO2/FTO上可生长出晶向为〈110〉的高质量VO2薄膜,在VO2/TiO2/FTO微结构两侧反复施加不同的脉冲电压,可观测到微结构具有非易失性相变存储特性,在67,68和69℃温度下的相变阈值电压分别为8.5,6.5和5.5V,相比多层膜结构的相变阈值电压降低了约37％.     

Spray deposited ZnO and Ga doped ZnO based DSSC with bromophenol blue dye as sensitizer: Efficiency analysis through DFT approach

Dye sensitized solar cells based on spray deposited ZnO and Ga doped ZnO (GZO) thin film were fabricated with Bromophenol Blue as the photo sensitizer. XRD results show the hexagonal wurtzite phase of ZnO and GZO thin films with c-axis growth orientation, and the diminished crystalline nature of GZO thin film as the effect of doping. FE-SEM results revealed the morphology induced internal light interaction capability of GZO thin film for better harvesting of photon energy. Photovoltaic studies showed that the DSSC fabricated with GZO thin film has obtained enhanced power conversion efficiency (1%) than the ZnO thin film based DSSC (0.2%), as a result of Ga doping. To investigate the obtained photovoltaic performance of the device, the electronic properties of Bromophenol Blue dye were theoretically analyzed with Density Functional Theory (DFT) study.