取向纳米ZnO/Cu_2O异质结阵列的制备及光电特性

以水热合成法制备的一维取向n型ZnO纳米线阵列为衬底,采用电化学沉积法在其上沉积生长一层p型Cu2O半导体包覆层,制备出了新型ZnO/Cu2O异质结纳米线阵列光敏器件.利用XRD、SEM、TEM、XPS、PL及光响应特性等测试方法对样品的形貌、晶体结构、化学成分及光电特性进行了分析表征.研究了生长条件对ZnO/Cu2O异质结纳米线阵列各种特性的影响.研究发现,适宜的沉积电压和沉积时间是保证ZnO/Cu2O异质结光敏器件具有适宜厚度核壳包覆层及较好光响应特性的关键因素.研究结果为ZnO及Cu2O半导体材料在光敏器件中的应用提供了实验基础.     

硅衬底上聚丙烯酰胺/氧化锌纳米线薄膜蓝色发光二极管

采用高分子络合软模板法利用高分子络合和低温氧化烧结反应,在硅衬底上自组装生长出顶面平滑具有六角柱形结构的ZnO纳米线,并基于此聚丙烯酰胺/ZnO纳米线体系构筑了聚合物基ZnO纳米线发光二极管器件,在相对低的阈值电压下实现了常温常压下电场驱动的蓝色发射光,并且其发光颜色可由其应用的激励电压方便地调控.几乎垂直排列的ZnO纳米线/高分子薄膜在器件中被作为发射层.该方法使用聚合物作为LED器件的粘结剂和发光层的分散介质,稳定了硅衬底上埋置在聚合物薄膜中的ZnO纳米线准阵列并对ZnO纳米晶的表面起钝化作用,防止发光猝灭.结果表明,新技术是一种低成本制备ZnO基紫外/蓝色发光材料的工艺,并且减少了以往工艺中要求ZnO薄膜p型掺杂的麻烦.     

聚3-辛基噻吩/MWNTs复合材料的导电性能研究

采用在氯仿溶液中超声共混, 制备聚3-辛基噻吩(P3OT)和多壁碳纳米管(MWNTs)复合材料. 当MWNTs掺杂量为3%时复合材料的电导率为1.43 S•m－1, 达到纯MWNTs的电导率水平. 用FTIR光谱, TG, UV-Vis光谱, XPS和FESEM进行研究分析, 认为MWNTs的离域电子与P3OT主链上的π电子之间形成π-π共轭, 增加了P3OT主链的有效共轭度, 被掺杂的P3OT具有很高的电导率, 提高了复合材料的导电性能. MWNTs与被掺杂的P3OT组成相对独立的导体单元, 对复合材料的导电网络形成起着主要作用.     

微纳米结构复合表面的疏水-冰性能

通过软复型和水热法制备出一种由有机材料和ZnO纳米棒组成的微纳米结构复合表面,这种表面的微米结构是周期为300μm、高度为70μm的锯齿状结构,ZnO纳米线的直径为300~500 nm,长度为2~3μm.这种有机材料和ZnO纳米线复合成的表面经过全氟硅烷修饰后,具有良好的低黏滞特性和低温超疏水性(约为150°)以及较长的结冰延时性(6000~7630 s),实验结果对设计表面低温疏水/疏冰材料具有参考价值.     

聚吡咯及其复合热电材料研究进展

聚吡咯(PPy)以其环境稳定性好、低毒、可调的导电性等优点,在热电材料研究方面日益受到人们的关注。采用纳米结构导电聚合物或将有机导电聚合物材料与高导电性的碳纳米粒子进行复合制备聚合物/碳纳米粒子复合材料,可以有效地改善其热电性能。本文结合该领域近年来的研究进展,重点讨论了PPy及其复合热电材料的研究结果,对一维纳米结构PPy的制备也进行了论述。     

纳米ZnO/聚合物器件的制备及应用

近年来,氧化锌(ZnO)由于依赖于尺寸、形状的光电特性而备受关注。纳米ZnO尺寸较小、表面能高,易团聚,使其在光电、生物等方面的应用受到限制。将其与聚合物复合或组装,不但能稳定纳米ZnO,而且可以使纳米ZnO/聚合物复合材料具有优良性能。本文综述了近年来纳米ZnO/聚合物复合材料的制备方法(聚合物辅助、表面接枝、转移分散等法)及纳米ZnO/聚合物器件在电致发光、光伏电池、荧光成像等方面的应用,并对纳米ZnO/聚合物复合材料的发展做了展望。     

聚苯胺纳米线/SnO2复合光催化材料的光化学制备与性能

将具有确定形态的聚苯胺(PANI)纳米线作为复合单元, 直接分散在SnSO₄和H₂SO₄的混合溶液中, 通 过紫外光照射获得PANI纳米线/SnO₂纳米颗粒复合材料. 对复合材料的形态和成分进行了分析, 发现二者 相互交织在一起且部分颗粒直接生长在纳米线上. 以罗丹明B溶液为目标降解污染物研究了复合材料在低 功率紫外灯下的光催化活性. 结果表明, PANI纳米线可以明显增强SnO₂的光催化活性, 且增强效果与光照 复合时间呈规律性变化, 在最优复合时间下复合材料的光催化活性是纯SnO₂的近3倍. 通过对能级结构与光催化反应过程的测试分析, 认为Z型异质结的形成促进了光生电子-空穴的分离, 进而增强了材料的光催化活性.     

聚丙烯/多壁碳纳米管复合材料的热性能和流变性能

用熔融共混法制备了聚丙烯多壁碳纳米管(PP MWNTs)复合材料,TGA研究表明在氮气气氛下碳纳米管显著增加了聚丙烯基体的热稳定性.3wt%MWNTs可使PP热分解起始温度提高44℃.非等温结晶研究表明MWNTs对PP基体的结晶行为没有明显的影响.流变测试结果表明PP MWNTs复合材料的储能模量G′和损耗模量G″随着MWNTs含量增加逐渐增大.1wt%MWNTs的PP聚合物的零剪切粘度最低,5wt%MWNTs的PP聚合物的零剪切粘度最高,PP和3wt%MWNTs的PP纳米聚合物的零剪切粘度居于二者之间,随着频率的增加,剪切稀化作用越来越明显,呈现出假塑性流体行为.含5wt%MWNTs的PP复合材料的体积和表面电阻率与纯PP相比分别下降了9个和4个数量级,表明少量的MWNTs可以显著改变PP的电学性能.     

钙钛矿太阳能电池电子传输层的制备及应用

目前,有机-无机杂化钙钛矿太阳能电池(PSC)的器件效率已经超过25%。电子传输层作为PSC中的重要组成部分在提取和传输光生电子,阻挡空穴,修饰界面,调节界面能级和减少电荷复合等方面起着关键作用。无机n型材料,例如TiO₂、ZnO、SnO₂和其他金属氧化物材料具有成本低和稳定性好的特点,经常在传统PSC中被用作电子传输层(ETL)。有机n型材料,例如富勒烯及其衍生物、萘二酰亚胺聚合物和小分子,具有良好的成膜性能及强的电子传输性能,经常在反式PSC中被用作ETL。本综述详细介绍了PSC中电子传输层的作用机理和制备方法;重点总结了金属氧化物材料、有机分子材料、复合材料和多层分子材料电子传输层和其改性手段的最新研究进展;最后,展望了电子传输层材料朝着高性能PSC的实际应用和发展前景。     

聚(2-甲氧基-5-辛氧基)对苯乙炔/单壁碳纳米管复合材料的光物理性能研究

采用原位脱氯化氢缩合聚合法制备了聚(2-甲氧基-5-辛氧基)对苯乙炔/单壁碳纳米管(PMOCOPV/SWNTs)复合材料. 红外光谱和拉曼光谱证实了在SWNTs表面的包覆层为PMOCOPV. 高分辨透射电子显微镜观察发现, PMOCOPV/SWNTs复合材料直径为4~7 nm, 其中PMOCOPV包覆层厚度约为2~5 nm. 紫外-可见吸收光谱表明, 随着SWNTs含量的增加, PMOCOPV/SWNTs的吸收发生蓝移且强度提高. 荧光光谱研究表明, 随着SWNTs含量的增加, PMOCOPV/SWNTs的最大发射波长发生蓝移且强度减小, SWNTs与PMOCOPV之间形成了光致电子转移体系, 使π电子离域程度增加, 导致荧光量子效率降低. 根据E_g与入射光子能量hν的关系, 拟合了PMOCOPV/SWNTs薄膜的光学禁带宽度, 发现随着SWNTs含量的增加, E_g逐渐减小. 采用简并四波混频方法测试其三阶非线性极化率χ⁽³⁾, 结果表明, 随着SWNTs含量的增加, PMOCOPV/SWNTs复合体的非线性光学响应逐渐增强, 说明PMOCOPV与SWNTs之间形成了分子间光致电子转移体系, 产生了复杂的分子间π-π电子非线性运动.     

Engineered Molecular Chain Ordering in Single‐Walled Carbon Nanotubes/Polyaniline Composite Films for High‐Performance Organic Thermoelectric Materials

Single‐walled carbon nanotubes (SWNTs)/polyaniline (PANI) composite films with enhanced thermoelectric properties were prepared by combining in situ polymerization and solution processing. Conductive atomic force microscopy and X‐ray diffraction measurements confirmed that solution processing and strong π–π interactions between the PANI and SWNTs induced the PANI molecules to form a highly ordered structure. The improved degree of order of the PANI molecular arrangement increased the carrier mobility and thereby enhanced the electrical transport properties of PANI. The maximum in‐plane electrical conductivity and power factor of the SWNTs/PANI composite films reached 1.44×10³ S cm^?1 and 217 μW m^?1 K^?2, respectively, at room temperature. Furthermore, a thermoelectric generator fabricated with the SWNTs/PANI composite films showed good electric generation ability and stability. A high power density of 10.4 μW cm^?2 K^?1 was obtained, which is superior to most reported results obtained in organic thermoelectric modules.     

溶液共混法制备聚苯乙烯/多壁碳纳米管复合导电材料

碳纳米管(CNTs)自从1991年被发现以来,以其特有的力学、电学和化学性能以及独特的准一维管状分子结构和在未来高科技领域中所具有的许多潜在应用价值,迅速成为化学、物理及材料科学领域的研究热点[1]。碳纳米管的C-C共价键链段结构与高分子链段结构相似,能通过配位键作用与高分     

Thermoelectric properties of nanocomposite thin films prepared with poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) and graphene

Carbon nanotubes (CNTs), either single wall carbon nanotubes (SWNTs) or multiwall carbon nanotubes (MWNTs), can improve the thermoelectric properties of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT?:?PSS), but it requires addition of 30-40 wt% CNTs. We report that the figure of merit (ZT) value of PEDOT?:?PSS thin film for thermoelectric property is increased about 10 times by incorporating 2 wt% of graphene. PEDOT?:?PSS thin films containing 1, 2, 3 wt% graphene are prepared by solution spin coating method. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy analyses identified the strong π-π interactions which facilitated the dispersion between graphene and PEDOT?:?PSS. The uniformly distributed graphene increased the interfacial area by 2-10 times as compared with CNT based on the same weight. The power factor and ZT value of PEDOT?:?PSS thin film containing 2 wt% graphene was 11.09 μW mK(-2) and 2.1 × 10(-2), respectively. This enhancement arises from the facilitated carrier transfer between PEDOT?:?PSS and graphene as well as the high electron mobility of graphene (200,000 cm(2) V(-1) s(-1)). Furthermore the porous structure of the thin film decreases the thermal conductivity resulting in a high ZT value, which is higher by 20% than that for a PEDOT?:?PSS thin film containing 35 wt% SWNTs.     

The effect of length of single‐walled carbon nanotubes (SWNTs) on electrical properties of conducting polymer–SWNT composites

DC conductivity of conjugated polymer‐single‐walled carbon nanotube (SWNT) composite films has been measured for different SWNT concentrations. The composite was prepared by dispersing SWNTs in the poly (3‐octylthiophene), P3OT matrix already dissolved in xylene. The conductivity of the composite films showed a rapid increase as the SWNT concentration increases beyond a certain value. This behavior is explained in terms of percolating paths provided by the SWNTs in the volume of polymer matrix. To investigate the effect of length of nanotubes on the percolation conductivity, different SWNT samples were employed with similar diameter but varying tube lengths. It was found that the conductivity of the composite films is strongly dominated by the length of the nanotubes. Lower percolation limit and high conductivity value of composite films is observed for longer nanotubes. Furthermore, the conductivity is observed to be dependent on the size of the host polymer molecule also. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 89–95, 2010     

Air‐tolerant Fabrication and Enhanced Thermoelectric Performance of n‐Type Single‐walled Carbon Nanotubes Encapsulating 1,1′‐Bis(diphenylphosphino)ferrocene

The thermally‐triggered n‐type doping of single‐walled carbon nanotubes is demonstrated using 1,1′‐bis(diphenylphosphino)ferrocene, a novel n‐type dopant. Through a simple thermal vacuum process, the phosphine compounds are moderately encapsulated inside single‐walled carbon nanotubes. The encapsulation into SWNTs is carefully characterized using Raman/X‐ray spectroscopy and transmission electron microscopy. This easy‐to‐handle doping with air‐stable precursors for n‐type SWNTs enables the large‐scale fabrication of thermoelectric materials showing an excellent power factor exceeding approximately 240 μW mK^?2.     

Effect of carbon nanotubes on mechanical and electrical properties of polyimide/carbon nanotubes nanocomposites

Multi-walled carbon nanotubes (MWNTs) reinforced polyimide nanocomposites were synthesized by in situ polymerization using 4,4′-oxydianilline, MWNTs, and pyromellitic dianhydride followed by casting, evaporation and thermal imidization. A homogeneous dispersion of chemically modified MWNTs was achieved in polyimide matrix as evidenced by scanning electron microscopy and atomic force microscopy. The incorporation of the modified MWNTs enhanced the mechanical properties of the polyimide due to the presence of strong interfacial interaction between the polymer matrix and the nanotubes in polymer composites. The resultant polyimide/MWNTs nanocomposites were electrically conductive with significant conductivity enhancement at 3 wt% MWNTs, which is favorable for many practical uses.     

PET-SWNT nanocomposites through ultrasound assisted dissolution-evaporation

Poly(ethylene terephthalate) (PET) based nanocomposites have been prepared with single walled carbon nanotubes (SWNTs) through an ultrasound assisted dissolution-evaporation method. Differential scanning calorimetry studies showed that SWNTs nucleate crystallization in PET at weight fractions as low as 0.3%, as the nanocomposite melt crystallized during cooling at temperature 24 °C higher than neat PET of identical molecular weight. Isothermal crystallization studies also revealed that SWNTs significantly accelerate the crystallization process. Mechanical properties of the PET-SWNT nanocomposites improved as compared to neat PET indicating the effective reinforcement provided by nanotubes in the polymer matrix. Electrical conductivity measurements on the nanocomposite films showed that SWNTs at concentrations exceeding 1 wt% in the PET matrix result in electrical percolation. Comparison of crystallization, conductivity and transmission electron microscopy studies revealed that ultrasound assisted dissolution-evaporation method enables more effective dispersion of SWNTs in the PET matrix as compared to the melt compounding method.     

Surface initiated ring-opening polymerization of l-proline N-carboxy anhydride from single and multi walled carbon nanotubes

Ring-opening surface initiated polymerization of l-proline N-carboxyanhydride was performed from amine functionalized single (SWNTs) and multi walled carbon nanotubes (MWNTs). The primary amines were grafted on the surfaces via a well-studied Diels–Alder cycloaddition. The initiator attachment helped the debundling of carbon nanotubes as shown by atomic force microscopy (AFM) studies where only small aggregates were observed. Thermogravimetric analysis revealed high wt% of grafted polyproline on the carbon nanotubes surface after the ring-opening polymerization. AFM studies showed a rather uniform layer of grafted polyproline from both MWNTs and SWNTs. The grafting of PLP on the surface was also verified by FTIR and Raman spectroscopy as well as ¹H NMR in CDCl₃/d-TFA. The polyproline grafted carbon nanotubes (CNTs) were readily dissolved in organic solvents in contrast to the insoluble pristine and amine-functionalized CNTs.     

Tl_2O_3/聚-N-乙烯基咔唑复合纳米线的研究

微型化是纳米科技发展的关键驱动力之一，然而使用现行的光刻技术生产大规模集成电路器件的技术已经接近极限尺寸（～0．8μm）．1982年STM的研制成功使得在纳米尺寸上进行操作成为可能[1－3]同时，LB技术正在应用于纳米粒子薄膜的制备中[4]．进一步利用Iangmuir单层膜诱导控制