95%高双面率异质结太阳电池的叠层减反射研究

本文通过PV Lighthouse模拟了硅片厚度(从50μm至200μm)对晶硅异质结(SHJ)太阳电池的光学吸收及光生电流密度的影响,剖析了电池柔性化面临的瓶颈问题,并模拟了不同厚度的TCO/MgF₂与TCO/SiO₂减反射结构,获得了最佳光生电流密度。通过热蒸发制备了MgF₂薄膜,射频磁控溅射制备了SiO₂薄膜,经过优化构建了具有高透过率(92.56%)的MgF₂/SiO₂叠层减反射结构,将器件入光面反射率从6.70%降低至5.46%。在SHJ电池背面应用MgF₂/SiO₂叠层减反射结构,正面辅以单层SiO₂或MgF₂减反射薄膜,背面入光时的外部量子效率(EQE)显著提高了2.35%,使短路电流密度提升1.10 mA/cm²以上。该叠层减反射方案实现了95.16%的超高双面率,对提升双玻组件的发电量具有重要意义。     

软模板导向合成多级孔丝光沸石及其苯的苄基化催化性能

通常认为丝光沸石是具有一维孔道结构的微孔沸石, 在涉及大分子的催化反应中存在较为严重的扩散限制。以双季铵型表面活性剂C₁₈H₃₇N⁺(CH₃)₂C₆H₁₂N⁺(CH₃)₂C₆H₁₃(Br^-)₂(C_18-6-6Br₂)作为软模板, 在水热条件下制备了多级孔丝光沸石分子筛。采用XRD、FT-IR、SEM、TEM、TG-DTG、N₂物理吸附、NH₃-TPD等手段对样品的晶体结构和物化性能进行了表征。结果表明, 加入C_18-6-6Br₂制备了纳米棒定向排列的多级孔丝光沸石, 而且可通过改变合成体系中C_18-6-6Br₂/SiO₂的比值, 对样品的晶粒尺寸、介孔表面积和介孔孔容进行系统调变。在苯与苯甲醇的苄基化反应中, 多级孔样品比传统微孔丝光沸石表现出更好的苄基化反应催化性能和显著提高的反应速率。多级孔丝光沸石优异的催化性能归因于介孔的存在使其具有更多的可接近活性位和更优异的质量传输性质, 这种独特的多级孔丝光沸石在大分子催化转化反应中具有较大的应用潜力。     

双金属催化剂Ni-Co/SiO2空心球的可控制备及催化性能

以二氧化硅为模板, 采用牺牲模板/界面反应法制备具有介孔结构的碱式硅酸镍钴空心球。采用透射电子显微镜(TEM)、X 射线衍射(XRD)、氮气吸脱附曲线(BET)和程序升温还原(TPR)等方法, 对样品的结构和形貌进行了表征, 探索了碱式硅酸镍钴空心球还原规律, 并研究了双金属催化剂Ni-Co/SiO₂的催化性能。研究发现, 140℃下反应6 h, 产物为核壳结构, 反应12 h时变为空心球结构; 在氢气气氛中800℃下反应5 h, 碱式硅酸镍钴被完全还原为Ni-Co/SiO₂, 还原前后形貌基本不变, 但比表面积有所减小, 孔径增大。Ni-Co/SiO₂空心球用于催化硝基苯加氢反应1 h后, 硝基苯的转化率为67%, 比商用Raney Ni 提高约28%。     

具有梯度渐变折射率的超疏水减反膜的制备及其性能

具有梯度折射率的减反膜可以在更宽光谱波段和更大入射光角度实现减反射性能。本研究利用溶胶-凝胶和溶剂热法分别合成实心氧化硅(SiO₂)、空心氧化硅(H-SiO₂)和空心氟化镁(MgF₂)溶胶, 利用浸渍-提拉法在玻璃双面镀制SiO₂/H-SiO₂/MgF₂梯度折射率薄膜。结果表明, 在380~1600 nm波长, 镀膜基片在光垂直入射时透光率高达99.88%, 当光以0°~45°入射时, 平均透光率均高于97.85%, 即使光以75°入射时, 最高透光率仍达95.51%。同时发现, 经十六烷基三甲氧基硅烷(HDTMOS)修饰, 薄膜疏水角达到150.6°, 显示出良好的疏水自清洁效果。     

PMMA模板制备LaMnO3及其电化学性能研究

采用PMMA(聚甲基丙烯酸乙酯)根据Stober-Frink法制备出PMMA微球,并将其作为模板剂,以柠檬酸为络合剂,乙醇和蒸馏水为溶剂,通过混合搅拌、沉淀和去除模板剂等过程来制备得到LaMnO₃。利用粉末X射线衍射技术(XRD)、场发射扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、N₂吸附-脱附等手段表征分析了催化剂样品LaMnO₃,并对其进行了电化学性能测试。结果表明,以PMMA微球为模板可制备出球形空洞的多孔LaMnO₃,其具有良好的氧还原反应(ORR)活性和氧析出反应(OER)活性,23.005 m²/g的比表面积远大于由共沉淀法制备的LaMnO₃,当作为铝空气电池阴极催化剂材料时,相比于共沉淀法制备的LaMnO₃其恒流放电稳定、放电电压高。     

增强改性SiO2气凝胶复合材料的研究进展

SiO₂气凝胶是一种含有纳米介孔结构的轻质固体材料，具有高孔隙率、高比表面积、低导热性、低介电性等特性，在隔热、吸附、吸声、发光、催化、电子等工业领域具有广阔的应用前景。但SiO₂气凝胶自身孔结构存在易碎、易坍塌等缺陷，导致应用受到较大限制。在保持SiO₂气凝胶良好特性的前提下，对其进行增强改性制备力学性能优良的SiO₂气凝胶复合材料是近年来的研究热点。本文报道了无机/有机纤维增强改性SiO₂气凝胶、有机聚合物增强改性SiO₂气凝胶及无机物掺杂增强改性SiO₂气凝胶等复合材料的主要制备工艺过程、材料综合性能表现及增强改性机制，探讨了增强改性SiO₂气凝胶复合材料研究进展及重点方向，以期为增强改性SiO₂气凝胶复合材料的研究和应用提供新的设计思路。      

溅射功率对磁控溅射法制备MgF2薄膜组织和性能的影响

为了减少磁控溅射法沉积MgF₂薄膜的F贫乏缺陷, 在工作气体Ar₂中加入SF₆作为反应气体, 在石英玻璃衬底上用射频磁控溅射法制备了MgF₂薄膜, 研究了溅射功率对MgF₂薄膜化学成分、微观结构和光学性能的影响。结果表明, 随着溅射功率从115 W增加到220 W, F: Mg的原子比不断增加, 185 W时达到2.02, 最接近理想化学计量比2 : 1;薄膜的结晶度先提高后降低, 最后转变为非晶态; MgF₂薄膜的颗粒尺寸先是有所增加, 轮廓也变得更加清晰, 最后又变得模糊。MgF₂薄膜的折射率先减小后增大, 在185 W时获得最低值, 550 nm波长的折射率1.384非常接近MgF₂块体晶体;镀膜玻璃在300~1100 nm范围内的透光率(以下简称薄膜透光率)先增大后减小, 185 W时达到94.99%, 比玻璃基底的透光率高出1.79%。     

模板剂F127对介孔SnO2的孔结构及电化学性能的影响

以SnCl₄·5H₂O和尿素为原料, 嵌段聚醚F127(EO₁₀₆-PO₇₀-EO₁₀₆)为模板剂, 通过水热法制备了介孔SnO₂材料。XRD、TEM和BET等分析结果表明, 模板剂F127添加量对介孔SnO₂的孔结构有重要影响。F127添加量增加, SnO₂比表面积增大, 孔容增大, 孔径分布变宽。电化学测试结果表明, 介孔的存在不仅能为锂离子脱嵌提供通道, 而且可以缓冲SnO₂的体积膨胀, 从而提高介孔SnO₂负极材料的电化学性能; 当F127添加量为6.0 g时, 所制备SnO₂具有124 m²/g的比表面积, 平均孔径为4.94 nm, 表现出最佳的循环性能和倍率性能, 在60 mA/g的电流密度下经30次循环后, 其可逆容量仍保持在434 mAh/g; 循环伏安测试表明部分高活性Li₂O的可逆还原提供了附加的可逆容量。     

石墨烯基介孔锰铈氧化物催化剂:制备和低温催化还原NO

锰铈氧化物由于较强的氧化还原活性、优良的低温脱硝性能,已被广泛用于选择性催化还原(SCR)脱硝反应,但是锰铈氧化物存在活性组分易团聚、比表面积较低等问题,限制其催化剂活性的提高。本研究以介孔结构的石墨烯基SiO₂(G@SiO₂)纳米材料为模板,采用水热法制备了系列石墨烯基介孔锰铈氧化物(G@MnO_x-CeO₂)催化剂,并考察了该催化剂在低温下(100～300℃)的SCR脱硝性能。结果表明,与石墨烯基铈氧化物(G@CeO₂)相比,G@MnO_x-CeO₂催化剂具有较高脱硝活性。当Mn、Ce与模板G@SiO₂质量比分别为0.35、0.90时, G@Mn(0.35)Ce(0.9)催化剂的脱硝活性最佳, 220℃下NO转化率达到最高(80%)。添加适量MnO_x,提高了G@MnO_x-CeO₂催化剂的比表面积、孔容,降低了催化剂的结晶度;并且MnO_x<...     

微波法制备羟基磷酸铜及光催化降解性能研究

以氯化铜、磷酸二氢钠和尿素为原料, 加入模板剂十二烷基硫酸钠(SDS), 采用微波辅助加热法制备了具有不同规则结构的晶态羟基磷酸铜。实验研究了CuCl₂与NaH₂PO₄的摩尔比、模板剂种类和原料浓度等因素对合成羟基磷酸铜晶体的影响。产物采用XRD、SEM和Raman等进行表征, 并通过降解甲基蓝溶液(MB)测试了羟基磷酸铜的催化性能, 探讨了制备条件对产物光催化降解性能的影响。结果表明, 当n(Cu)/n(P)为2, [PO₄^3-]= 0.0025 mol/L, 微波加热温度80℃, 反应时间30 min, 尿素用量6.0 g, SDS用量为0.10 g时制备的羟基磷酸铜具有良好的光催化效果。实验还测试了催化剂的表面光电压谱, 并使用苯甲酸作为荧光探针, 叔丁醇为羟基自由基捕获剂初步验证了光催化反应中羟基磷酸铜的催化机理。     

Burning velocity measurements of nitrogen-containing compounds

Burning velocity measurements of nitrogen-containing compounds, i.e., ammonia (NH₃), methylamine (CH₃NH₂), ethylamine (C₂H₅NH₂), and propylamine (C₃H₇NH₂), were carried out to assess the flammability of potential natural refrigerants. The spherical-vessel (SV) method was used to measure the burning velocity over a wide range of sample and air concentrations. In addition, flame propagation was directly observed by the schlieren photography method, which showed that the spherical flame model was applicable to flames with a burning velocity higher than approximately 5 cm s⁻¹. For CH₃NH₂, the nozzle burner method was also used to confirm the validity of the results obtained by closed vessel methods. We obtained maximum burning velocities (S_u0,max) of 7.2, 24.7, 26.9, and 28.3 cm s⁻¹ for NH₃, CH₃NH₂, C₂H₅NH₂, and C₃H₇NH₂, respectively. It was noted that the burning velocities of NH₃ and CH₃NH₂ were as high as those of the typical hydrofluorocarbon refrigerants difluoromethane (HFC-32, S_u0,max = 6.7 cm s⁻¹) and 1,1-difluoroethane (HFC-152a, S_u0,max = 23.6 cm s⁻¹), respectively. The burning velocities were compared with those of the parent alkanes, and it was found that introducing an NH₂ group into hydrocarbon molecules decreases their burning velocity.     

Optical properties and surface morphology of near infrared multilayer antireflection coatings

Theoretical and experimental studies on multilayer antireflection (AR) coatings useful in the near infrared region, covering 1200 to 2000 nm are carried out, in which the relative merits and demerits of using a low refractive index magnesium fluoride (MgF₂), along with a high refractive index Substance H2 (Sub2) material of E. Merck, in comparison to silicon dioxide (SiO₂) and Sub2, are specifically investigated. It is seen that MgF₂ together with Sub2 produces wider band antireflection coatings, with lower ripple and integrated reflection loss (IRL), R^*, whereas SiO₂/Sub2 combination produces AR coatings with medium spectral coverage, and the coatings are free of structural defects, which in turn are highly durable against adverse environmental conditions.     

Study on the mechanism of NH3-selective catalytic reduction over CuCexZr1--<?Pub Caret?>x/TiO2

Copper--cerium--zirconium catalysts loaded on TiO₂ prepared by a wet impregnation method were investigated for NH₃-selective catalytic reduction (SCR) of NO_x. The reaction mechanism was proposed on the basis of results from in situ diffuse reflectance infrared transform spectroscopy (DRIFT). When NH₃ is introduced, ammonia bonded to Lewis acid sites is more stable over CuCe_0.25Zr_0.75/TiO₂ at high temperature, while Br?nsted acid sites are more important than Lewis acid sites at low temperature. For the NH₃+NO+O₂ co-adsorption, NH₃ species occupy most of activity sites on CuCe_0.25Zr_0.75/TiO₂ catalyst, and mainly exist in the forms of NH₄⁺ (at low temperature) and NH₃ coordinated (at high temperature), playing a crucial role in the NH₃-SCR process. Two different reaction routes, the L-H mechanism at low temperature (<200°C) and the E-R mechanism at high temperature (>200°C), are presented for the SCR reaction over CuCe_0.25Zr_0.75/TiO₂ catalyst.     

Application of decomposed species generated by a heated catalyzer to ULSI fabrication processes

In this paper we report on surface nitridation of SiO₂ and on photoresist removal by using species decomposed from NH₃ or H₂ and generated by a heated tungsten catalyzer. The top surface of SiO₂/Si(100) is nitrided at temperatures as low as 300 °C using species decomposed from NH₃ species. The removal of heavy-doped, as high as 1×10¹⁶ cm⁻², ion-implanted photoresist is realized using atomic hydrogen.     

CH3COONa处理HZSM-5分子筛及其催化性能

采用不同浓度的CH₃COONa溶液和常规碱(NaOH和Na₂CO₃)溶液处理HZSM-5分子筛, 对处理前后的HZSM-5分子筛负载Pt, 制备Pt/HZSM-5催化剂用于丙烷脱氢反应。利用X射线衍射(XRD)、X射线荧光光谱(XRF)、扫描电镜(SEM)、比表面测试仪(BET)、NH₃-TPD(程序升温脱附法)和H₂化学吸附等手段对处理前后的HZSM-5分子筛进行表征, 并考察了不同浓度的CH₃COONa溶液和常规碱溶液处理对HZSM-5分子筛的晶体结构、表面形貌、孔结构、表面酸性及丙烷脱氢性能的影响。结果表明, CH₃COONa溶液具有碱改性作用, 与常规碱溶液相比, 采用CH₃COONa溶液处理HZSM-5分子筛, 能够在对分子筛的晶体结构和表面形貌影响较小的基础上有效地引入介孔结构, 具有较好的可调控性; 随着CH₃COONa溶液浓度的增加, 丙烷脱氢反应的丙烷初始转化率和丙烯选择性先升高后降低, 当CH₃COONa溶液浓度为4.0 mol/L时, 丙烷初始转化率和丙烯选择性均达到最高值, 分别为34.5%和98.9%。     

Segregation of Cu in Cu (Ti) alloys during nitridation in NH3

Cu(Ti 27 at.%) alloys on SiO₂ were reacted in NH₃ for 30 min over the temperature range 400–700 °C. Rutherford backscattering spectrometry in conjunction with high resolution transmission electron microscopy were utilized to investigate reaction products. At 400–450 °C, Ti is observed to segregate to the free surface to react with NH₃, forming an Ti oxynitride layer. Above 500 °C, Ti segregates to both the free surface and to the alloy/SiO₂ interface, leaving relatively-pure Cu layer. Reaction between Ti and SiO₂ results in a TiO/Ti₅Si₃ bilayer structure. By use of high spatial resolution energy dispersive X-ray spcctroscopy, the presence of a Cu-containing layer at the TiO/Ti₅Si₃ interface is observed. This layer may also contain Ti, Si and/or O. We propose a mechanism for Cu segregation to this interface which requires Cu diffusion across TiO and subsequent dissociation of Ti₅Si₃. Thermodynamic calculations support this mechanism.     

ION-ASSISTED DEPOSITION OF OPTICAL THIN FILMS

Some useful materials, such as ZnS, MgF₂, ZrO₂, Ta₂O₅, HfO₂, and SiO₂, deposited using ion assisted deposition (IAD) are investigated as a function of ion energy and ion source type. Both optical and mechanical properties such as optical stability, absorption and scattering losses, laser damage threshold, and durability are examined.