Carbon nanotube based transparent conductive thin films

Carbon nanotube (CNT) based optically transparent and electrically conductive thin films are fabricated on plastic substrates in this study. Single-walled carbon nanotubes (SWNTs) are chemically treated with a mixture of concentrated sulfuric acid and nitric acid before being dispersed in aqueous surfactant-contained solutions. SWNT thin films are prepared from the stable SWNT solutions using wet coating techniques. The 100 nm thick SWNT thin film exhibits a surface resistivity of 6 kohms/square nanometer with an average transmittance of 88% on the visible light range, which is three times better than the films prepared from the high purity as-received SWNTs.     

Nanostructuring thin Au films on transparent conductive oxide substrates

Fabrication processes of Au nanostructures on indium-tin-oxide (ITO) surface by simple, versatile, and low-cost bottom-up methodologies are investigated in this work. A first methodology exploits the patterning effects induced by nanosecond laser irradiations on thin Au films deposited on ITO surface. We show that after the laser irradiations, the Au film break-up into nanoclusters whose mean size and surface density are tunable by the laser fluence. A second methodology exploits, instead, the patterning effects of standard furnace thermal processes on the Au film deposited on the ITO. We observe, in this case, a peculiar shape evolution from pre-formed nanoclusters during the Au deposition stage on the ITO, to holed nanostructures (i.e. nanorings), during the furnace annealing processes. The nanorings depth, height, width, and surface density are shown to be tunable by annealing temperature and time.     

Preparation of transparent and conductive cellulose nanocrystals/graphene nanoplatelets films

The manufacture of emerging products such as photovoltaic devices requires combinations of various novel materials to be leveraged into successful, scalable approach. In order to develop new electronic devices, it is necessary to find innovative solutions to the eco-sustainability problem of materials as substrates for circuits. We report on the demonstration of polymer solar cells fabricated on optically transparent and conductive graphene nanoplatelets (GNPs)–cellulose nanocrystals (CNC) film. The solar cells fabricated on the GNPs/CNC films display good rectification in the dark. Such GNPs–CNC functional films are expected to be attractive for eco-friendly electronics.     

P型透明导电氧化物LaCuOS的研究进展

透明导电氧化物半导体的出现开拓了光电子器件研究的新领域，但是缺少性能良好的P型材料就限制了透明导电氧化物的利用空间。LaCuOS由于其结构、电学和光学等方面具有许多的优点，成为近年来P型半导体的研究热点。介绍了P型LaCuOS薄膜的基本性质，综述了不同的制备工艺并对其光电学与应用方面进行了研究总结。     

Nano-hybrid shish-kebab: Isotactic polypropylene epitaxial growth on electrospun polyamide 66 nanofibers via isothermal crystallization

Polyamide 66 (PA 66) nanofibers, with the mean diameter of about 140 nm, were prepared by electrospinning. Nano-hybrid shish-kebab (NHSK) structure was achieved in PA 66 nanofibers/isotactic polypropylene (iPP) composites via isothermal solution crystallization. The morphology of such NHSK was observed by scanning electron microscopy (SEM). It was found that PA 66 nanofibers act as “shish”, and iPP crystals serve as “kebabs”. Furthermore, the concentration of iPP solution remarkably affects the morphology of the NHSK, i.e., the size of iPP crystals becomes much bigger with the increasing iPP solutions' concentration. The reason for this can be explained as that the high concentration of iPP solutions contain more free chains which can participate into the process of crystallization.     

Preparation of Al-doped ZnO thin films as transparent conductive substrate in dye-sensitized solar cell

We have prepared aluminum-doped Zinc oxide (AZO) thin films on glass substrates by rf magnetron sputtering technique using ZnO ceramic target in pure argon gas with different aluminum concentrations. The bandgap of the ZnO films slightly widens with increase in Al content and the lowest sheet resistance of AZO films with Al concentration of 4.3 at.% was obtained. The effects of post-annealing treatment on structural, electrical and optical properties of the AZO thin films were investigated. Using AZO thin film with 4.3 at.% Al as the transparent substrate, a titanium dioxide based dye-sensitized solar cell was constructed and a solar to electrical energy conversion efficiency of 2.9% was achieved under AM 1.5 solar simulated sunlight.     

Highly transparent conductive and near-infrared reflective ZnO:Al thin films

Al-doped ZnO (AZO) thin films have been prepared on glass substrates by pulsed laser deposition. The structural, optical, and electrical properties were strongly dependent on the growth temperatures. The lowest resistivity of 4.5 × 10⁻⁴ Ωcm was obtained at an optimized temperature of 350 °C. The AZO films deposited at 350 °C also had the high optical transmittance above 87% in the visible range and the low transmittance (<15% at 1500 nm) and high reflectance (∼50% at 2000 nm) in the near-IR region. The good IR-reflective properties of ZnO:Al films show that they are promising for near-IR reflecting mirrors and heat reflectors.     

Preparation of properties of SWNT/graphene oxide type flexible transparent conductive films

Single walled carbon nanotube (SWNT)/graphene oxide (GO) hybrid films were prepared by a facile bar coating method on a polyethylene terephthalate substrate using a mixed solution of SWCNTs and GO. An acryl type polymer was employed as a dispersion agent to obtain SWCNT and GO suspension in ethyl alcohol. The SWCNT/GO hybrid films were highly transparent and electrically conductive, showing 80% transmittance and 1.8 x 10(3) ohm/sq surface resistance. The surface resistance of the SWCNT/GO film could be further improved to 750 ohm/sq by hydrazine vapor reduction.     

还原氧化石墨烯/碳纳米管透明导电薄膜的制备及性能研究

使用天然植物多酚——单宁酸(TA)作为氧化石墨烯(GO)的还原剂,通过"一步法"实现了对GO的绿色还原和功能化.随后,将TA还原氧化石墨烯(RGO)和碳纳米管(SWCNT)结合起来,共同构筑具有三维结构的石墨烯/单壁碳纳米管(RGO/SWCNT)透明导电薄膜(TCFs).该薄膜有着良好的导电性(透光率为75.1％时,面...     

成膜参数对Au透明导电复合膜电性能的影响

介绍了用真空磁控溅射方法沉积的Au-氧化物透明导电复合膜，研究了沉积复合膜过程中，真空室温度、电压以及退火处理等因素对复合膜电性能的影响，研究表明复合膜的电阻呈正温度系数，电阻低值对应于适宜的电压，从而对改善复合膜的光学、电性能及物理机械性能提供了很好的思路。     

Graphene-silica composite thin films as transparent conductors

Transparent and electrically conductive composite silica films were fabricated on glass and hydrophilic SiOx/silicon substrates by incorporation of individual graphene oxide sheets into silica sols followed by spin-coating, chemical reduction, and thermal curing. The resulting films were characterized by SEM, AFM, TEM, low-angle X-ray reflectivity, XPS, UV-vis spectroscopy, and electrical conductivity measurements. The electrical conductivity of the films compared favorably to those of composite thin films of carbon nanotubes in silica.     

氧化锌掺钇透明导电薄膜的制备及光电特性研究

采用射频磁控溅射法,室温下在玻璃衬底上制备出了具有良好附着性、低电阻率和高透过率的新型透明导电薄膜YZO(ZnO掺杂Y2O3简称YZO)。在薄膜厚度为600nm的情况下,研究了薄膜电学特性随溅射功率和溅射气压的变化情况。X射线衍射谱表明YZO薄膜是多晶膜,具有ZnO的六角纤锌矿结构,最佳取向为(002)方向。最佳溅射条件下制备的薄膜电阻率为8.71×10-4Ω.cm,在可见光范围内平均透过率达到92.3%,禁带宽度为3.57eV。     

Fabrication and evaluation of polyamide 6 composites with electrospun polyimide nanofibers as skeletal framework

In this study, two types of polyimide (PI) nanofiber mats, including (1) the mats consisting of (almost) randomly overlaid PI nanofibers and (2) the mats consisting of highly aligned PI nanofibers, were prepared by the materials-processing technique of electrospinning. The nanofiber mats were subsequently used to develop composites with polyamide 6 (PA6) via the composites – fabrication method of polymer melt infiltration lamination (PMIL). Owing to superior mechanical properties (i.e., the tensile strength and modulus were 1.7 GPa and 37.0 GPa, respectively) and large specific surface area of electrospun PI nanofibers, the PI/PA6 composites with PI nanofiber mats as skeletal framework demonstrated excellent mechanical properties. In particular, the PI/PA6 composite containing 50 wt.% of aligned PI nanofibers had the tensile strength and modulus of 447 MPa and 3.0 GPa along the longitudinal direction, representing ～700% and ～500% improvements as compared to neat PA6.     

Thermally stable, highly conductive, and transparent Ga-doped ZnO thin films

Highly conductive and transparent films of Ga-doped ZnO (GZO) have been prepared by pulsed laser deposition using a ZnO target with Ga₂O₃ dopant of 3 wt.% in content added. Films with resistivity as low as 3.3 × 10^− 4 Ω cm and transmittance above 80% at the wavelength between 400 and 800 nm can be produced on glass substrate at room temperature. It is shown that a stable resistivity for use in oxidation ambient at high temperature can be attained for the films. The electrical and optical properties, as well as the thermal stability of resistivity, of GZO films were comparable to those of undoped ZnO films.     

Control of thickness uniformity and grain size in graphene films for transparent conductive electrodes

Large-scale and transferable graphene films grown on metal substrates by chemical vapor deposition (CVD) still hold great promise for future nanotechnology. To realize the promise, one of the key issues is to further improve the quality of graphene, e.g., uniform thickness, large grain size, and low defects. Here we grow graphene films on Cu foils by CVD at ambient pressure, and study the graphene nucleation and growth processes under different concentrations of carbon precursor. On the basis of the results, we develop a two-step ambient pressure CVD process to synthesize continuous single-layer graphene films with large grain size (up to hundreds of square micrometers). Scanning electron microscopy and Raman spectroscopy characterizations confirm the film thickness and uniformity. The transferred graphene films on cover glass slips show high electrical conductivity and high optical transmittance that make them suitable as transparent conductive electrodes. The growth mechanism of CVD graphene on Cu is also discussed, and a growth model has been proposed. Our results provide important guidance toward the synthesis of high quality uniform graphene films, and could offer a great driving force for graphene based applications.     

Efficient coating of transparent and conductive carbon nanotube thin films on plastic substrates

Optically transparent and electrically conductive single-walled carbon nanotube (SWNT) thin films were fabricated at room temperature using a dip-coating technique. The film transparency and sheet resistance can be easily tailored by controlling the number of coatings. Aminopropyltriethoxysilane (APTS) was used as an adhesion promoter and, together with surfactant Triton X-100, greatly improved the SWNTs coating. Only five coats were required to obtain a sheet resistance of 2.05?[Formula: see text] and film transparency of 84?%T. The dip-coated film after post-deposition treatment with nitric acid has a sheet resistance as low as 130?[Formula: see text] at 69?%T. This technique is suitable for large-scale SWNT coating at room temperature and can be used on different types of substrates such as glass and plastics. This paper will discuss the role of the adhesion promoter and surfactant in the coating process.     

Reactive magnetron deposition of transparent conductive films

Transparent conductive films of In₂O₃:SnO₂ were reactively sputter deposited using a d.c. planar magnetron cathode in the moving deposition mode. Deposition times of 1.25–6 min were used to coat soda-lime glass 1 ft² with films of optical thickness one-half of a wavelength ($\text{λ =}\text{5500}\text{A}\text{?}$). The films had a higher transmittance and a lower sheet resistivity R_s than those generally used for the small liquid crystal displays in watches or calculators. The as-deposited films were either a hard transparent oxide with a high R_s or a soft opaque metal-rich material with a low R_s.After sputtering, the films were annealed in air or in a reducing atmosphere at temperatures from 300 to 500°C; thus optical transmissions in excess of 90% (including glass substrates) and sheet resistivities below Ω/□ were obtained. An investigation of films deposited onto sapphire demonstrated that impurity diffusion from soda-lime glass substrates may lead to an anomalous dependence of R_s on the annealing conditions.It was found that the type of film deposited, namely oxidized or metal rich, depended on the history of the target. The significance of this observation is discussed with reference to process reproducibility.     

氧化物透明导电膜的研究进展

介绍了透明导电薄膜主要的种类及发展过程,对氧化物透明导电薄膜的不同的制备工艺作了比较,并概括了氧化物透明导电薄膜的应用领域;在对氧化物透明导电薄膜的最新研究进展进行综合评述的同时,提出了透明导电薄膜的研究方向和目前亟待解决的问题.     

绒面ZAO透明导电膜的制备工艺研究

绒面ZAO(ZnO∶Al,氧化锌铝)透明导电膜在硅基薄膜太阳能电池领域应用前景广阔,本文利用直流磁控溅射方法,采用氧化锌铝陶瓷靶材制备了ZAO透明导电膜,并用自制的腐蚀液对膜层进行腐蚀以便形成太阳能电池所需要的表面凹凸起伏的绒面结构。研究了不同镀膜温度对膜层性能的影响,不同退火条件下膜层热稳定性的变化情况,不同腐蚀时间下膜层电阻、透过率以及表面形貌的变化,结果表明,在相同真空度、溅射功率和节拍的情况下,220℃下制备的ZAO透明导电膜膜层性能最好,腐蚀时间为30 s时获得的绒面效果好。