纳米银线柔性透明导电薄膜研究进展

随着时代的发展,柔性电子产品的应用越来越广。柔性透明导电薄膜是柔性电子器件中的重要组成部分,由于氧化铟锡并不适合应用到柔性电子器件中,寻找新一代材料引起了研究者的广泛关注。纳米银线作为一种新型的纳米材料,在纳米尺度上有很多新奇的性能,其优良的导电性及良好的光学性能被认为是替代氧化铟锡的最佳材料。本文主要综述了纳米银线柔性导电薄膜的研究进展,主要包括纳米银线导电油墨的物化性能、纳米银线柔性透明导电薄膜的常用制备方法以及主要应用领域。此外,还结合国内外纳米银线柔性透明导电膜的研究现状,指出该研究方向仍存在的一些挑战。     

柔性透明导电薄膜ZAO

随着电子器件向小型化和轻便化方向发展,柔性衬底的透明导电薄膜有望成为硬质衬底透明导电薄膜的更新换代产品,因此其研究备受关注.柔性透明导电薄膜ZAO具有优异的光电性能且资源丰富、成本低、对环境无污染,成为当前的研究热点.总结了近年来对柔性衬底材料处理的方法,介绍了柔性透明导电薄膜ZAO的结构和光电特性.评述了柔性ZAO薄膜的研究现状,并对其近期研究和应用工作做了展望.     

掺Al ZnO柔性透明导电薄膜研究进展

柔性透明导电薄膜ZAO具有优异的光电性能且资源丰富、成本低、对环境无污染,成为当前的研究热点.总结了近年来对柔性衬底材料处理的方法,分析了柔性透明导电薄膜的研究历史和现状.介绍了柔性透明导电薄膜ZAO的结构、光电特性、典型制备方法和应用前景.评述了柔性ZAO薄膜的研究现状,并对其近期研究和应用工作进行了展望.     

柔性透明导电氧化物薄膜的制备及其应用

柔性透明导电氧化物薄膜以其重量轻、不易碎、成本低等独特的优点而备受青睐,在塑料液晶显示、可折叠太阳能电池等领域得到广泛的应用.文章介绍了目前制备柔性透明导电氧化物薄膜的主要技术及其优缺点,总结了近年来对柔性衬底的处理方法,最后对柔性透明导电氧化物薄膜在各个领域的开发应用和未来的重点研究方向进行了展望.     

透明导电薄膜的研究进展

主要对目前国际上研究较多的几种透明导电薄膜,如金属膜、透明导电氧化物(TCO)薄膜(In2O3基、SnO2基、ZnO基及TiO2基薄膜)、p型材料及多层膜的性能、制备工艺、研究现状及最新进展进行了较为详细的阐述。介绍了一些较为特殊的透明导电薄膜材料。展望了透明导电薄膜未来的研究方向及发展前景。     

铜纳米线柔性透明导电薄膜的制备和性能研究

为寻找替代硬质氧化铟锡的新型柔性透明导电薄膜,采用液相还原法制备了大长径比的铜纳米线,并利用喷涂法实现铜纳米线柔性透明导电薄膜的制备。采用透射电子显微镜、扫描电子显微镜、X射线衍射仪对形貌和相结构进行了分析,并用紫外可见分光光度计和四探针测试仪分别对铜纳米线柔性透明导电薄膜的电学性能和光学性能进行了表征测试。结果表明,铜纳米线直径约为40 nm,长度为10～20μm,具有高长径比、分散性好、形貌规整的特点。同时,铜纳米线薄膜的电学和光学性能优异,方阻约为100Ω/,在550 nm处的光透射率为82%左右。该薄膜还具有较好的温度稳定性,耐温可达110℃,且其方阻在不同弯折程度下变化不大,具有良好的抗弯折性,可用于柔性可穿戴电子产品。     

纳米银线-环氧树脂复合导电薄膜的制备及其在柔性触控上的应用

纳米银线透明导电薄膜具有优异的光电性能和机械性能,有望取代传统的氧化铟锡材料应用于柔性光电器件中。为解决纳米银线的黏附性、柔韧性和稳定性问题,结合转印法和烷基硫醇修饰法制备了纳米银线-环氧树脂复合导电薄膜。在此过程中,首先应用十八烷基三氯硅烷对转移衬底进行疏水化处理以提升透明电极转印的良率;接着,对转印后的纳米银线进行烷基硫醇分子的自组装修饰,以进一步提升纳米银线透明导电薄膜的稳定性;最后在此基础上制备了柔性投射式电容触控屏。所制备的透明导电薄膜具有优异的综合性能:品质因数约为300(Rs=29.7Ω/□,T=96.2%);薄膜经过100次胶带测试后,电阻变化小于25%;在1 000次弯曲(弯曲半径为1mm)测试后,电阻几乎不发生变化;高温高湿下老化一个月,电阻变化小于20%。本文结合转印工艺以及分子修饰技术开发的纳米银线-环氧树脂复合导电薄膜以及柔性触控工艺,有望推广应用至其他柔性电子元件中。     

在柔性衬底上制备透明导电薄膜ZnO:Zr(英文)

采用射频磁控溅射法在室温柔性衬底PET上制备了掺锆氧化锌(ZZO)透明导电薄膜.利用不同方法提高了ZZO薄膜的电阻率而未使其可见光透过率降低.X射线衍射(XRD)和扫描电子显微镜(SEM)表明,ZZO薄膜为六角纤锌矿结构的多晶薄膜.在有机衬底和玻璃衬底上制备ZZO薄膜的择优取向不同,前者为(100)晶面,而后者为(002)晶面.在有ZnO缓冲层的PET衬底上制备的ZZO薄膜电阻率比直接生长在玻璃衬底样品上的小.通过优化参数,在PET衬底上制备出了最小电阻率为1.7×10-3Ω·cm、可见光透过率超过93%的ZZO薄膜.实验表明,镀膜之前在柔性衬底上沉积ZnO缓冲层能有效地提高ZZO薄膜的质量.     

利用射频磁控溅射法在柔性衬底上制备ZnO：Zr透明导电薄膜

利用射频磁控溅射法首次在室温水冷柔性衬底PET上制备出了可见光透过率高、电阻率低的掺锆氧化锌（ZnO：Zr）透明导电薄膜。X射线衍射和扫描电子显微镜表明,ZnO：Zr薄膜为六角纤锌矿结构的多晶薄膜,且具有平行于衬底方向的择优取向。实验获得ZnO：Zr薄膜的最小电阻率为1．55×10^-3Q·cm。实验制备的ZnO：Zr薄膜具有良好的附着性能,其可见光区平均透过率超过90％。     

非晶IGZO透明导电薄膜的L-MBE制备

报道了一种利用等离子辅助激光分子束外延技术(L-MBE)在石英衬底上制备IGZO透明导电薄膜的新工艺.该工艺在超高真空中进行,可以有效避免杂质和污染,提高薄膜的纯度和光学、电学性能.通过优化生长时的气体离化功率,在300W射频功率下,得到光学电学性能优良的非晶态IGZO透明导电薄膜,其可见光范围内透过率超过80%,其室温电子迁移率高达16.14cm2v-1s-1,明显优于目前薄膜晶体管(TFT)中常用的非晶硅和有机物材料.测试结果表明,采用此工艺制备的非晶态IGZO透明导电薄膜,具有优良的光学、电学特性,能代替非晶硅和有机物,提高TFT-LCD的性能,实现真正的全透明、高亮度及柔性显示.     

石墨烯透明导电膜研究与产业化进展

石墨烯作为一种新型二维碳纳米材料,具有许多独特的物理化学性质。尤其是其良好的透光性、高导电性、较好的机械强度等性质,近年来受到了透明导电膜领域的广泛关注与研究。与氧化铟锡(ITO)薄膜相比,石墨烯透明导电膜具有透光性和稳定性好、柔性更佳等特点。本文概述了石墨烯薄膜及其在透明导电膜应用的研究现状与产业化进展,分析了其在发展过程中存在的瓶颈,并展望了未来产业的发展趋势。     

Nanofiber/nanowires-based flexible and stretchable sensors

Nanofibers/nanowires with one-dimension(1D)nanostructure or well-patterned microstructure have shown distinctly advantages in flexible and stretchable sensor fields,owing to their remarkable tolerance against mechanical bending or stretching,outstanding electronic/optoelectronic properties,good transparency,and excellent geometry.Herein,latest summaries in the unique structure and properties of nanofiber/nanowire function materials and their applications for flexible and stretchable sensor are highlighted.Several types of high-performance nanofiber/nanowire-based flexible pressure and stretchable sensors are also reviewed.Finally,a conclusion and prospect for 1D nanofiber/nanowires-based flexible and stretchable sensors are also intensively discussed.This summary offers new insights for the development of flexible and stretchable sensor based 1D nanostructure in next-generation flexible electronics.     

AZO透明导电薄膜的制备

采用射频磁控溅射法在玻璃衬底上制备了ZnO:Al(AZO)透明导电薄膜,并借助XRD、SEM等表征方法,研究了溅射功率和衬底温度对薄膜结构、表面形貌及光电特性的影响。结果表明,制备薄膜的最佳溅射功率和衬底温度分别为180 W、200℃,在此条件下制备的AZO薄膜具有明显的c轴(002)择优取向,其最低方块电阻为18/□,在可见光范围内的平均透光率超过91%,且透明导电性能优于目前平板显示器的要求,有望取代现在市场上的主流氧化铟锡(ITO)薄膜。     

Preparation and properties of electrically conductive,flexible and transparent silver nanowire/poly (lactic acid) nanocomposites

As the everyday use of petroleum-based products has raised environmental concerns, there is an urgent need to replace them with green materials. In this work, an eco-friendly, highly conductive, flexible silver nanowire/poly (lactic acid) film has been fabricated through a simple casting method by embedding the silver nanowires (AgNWs) below the surface of the poly lactic acid (PLA) matrix. The fabricated film has a high optical transparency of 89.5% with a sheet resistance of 64.8 Ω/□ and a figure of merit (FoM) of 4.92 × 10⁻³ Ω⁻¹ which is comparable to that of indium tin oxide (ITO). These films demonstrate excellent flexibility, great adhesion, smooth surface with root mean square (RMS) roughness of 11.7 nm and high mechanical properties with tensile strength and Young's modulus of 39.8 (MPa) and 1.6 (GPa). The results obtained from different testing methods show that the AgNW/PLA nanocomposites are potential candidates in flexible electronics and optoelectronics.     

Flexible transparent conductive film based on silver nanowires and reduced graphene oxide

Silver nanowires (AgNWs) with diameter of 90—150 nm and length of 20—50 μm were successfully synthesized by a polyol process. Graphene oxide (GO) was prepared by Hummers method, and was reduced with strong hydrazine hy-drate at room temperature. The flexible transparent conductive films (TCFs) were fabricated using the mixed cellulose eater (MCE) as matrix and AgNWs and reduced graphene oxide (rGO) as conductive fillers by the improved vacuum fil-tration process. Then, the optical, electrical and mechanical properties of the AgNWs-rGO films were investigated. The results show that for the AgNWs-rGO film produced with the deposition densities of AgNWs and rGO as 110 mg·m-2 and 55 mg·m-2, the optical transmission at 550 nm is 88.4% with Rs around 891 Ω·sq-1, whereas the optical transmission for the AgNWs-rGO film with deposition densities of AgNWs and rGO of 385 mg·m-2 and 55 mg·m-2 is 79.0% at 550 nm with Rs around 9.6 Ω·sq-1. There is little overt increase in Rs of the AgNWS-rGO film after tape tests for 200 times. The bending test results indicate that the change in Rs of AgNWs-MCE film is less than 2% even after 200 cycles of compressive or tensile bending. The excellent mechanical properties of the AgNWs-rGO film can be attributed to the burying of AgNWs and rGO at the surface of MCE     

基于银纳米线的柔性透明电极的制备及性能研究

有机发光二极管(organic light emitting diodes, OLEDs)可以柔性制备,在未来的可穿戴应用上有广阔的发展前景,而柔性透明电极(flexible transparent electrode, FTE)的性能直接影响着柔性OLED的性能。本文基于银纳米线(AgNWs)和聚(3,4-乙烯二氧噻吩)∶聚苯乙烯磺酸(PEDOT∶PSS)制备了FTE,并采用甲醇浸渍、氩等离子处理、紫外辐射3种不同的方式对该电极进行处理,优化FTE的光电性能。研究发现：甲醇浸渍,可减少AgNWs上聚合物的包覆;等离子体处理和紫外辐射,可对AgNWs进行焊接;而两种方式的协同作用则可以对FTE的光电性能进一步优化。实验获得最优FTE的方阻为14.18Ω/sq,在550 nm处的透过率可达到84%以上。经过500次弯曲测试后,FTE的方阻变化率低于15%。本文的工作对FTE的制备及优化提供了可行性方案。     

All-solution-processed foldable transparent electrodes of Ag nanowire mesh and metal matrix films for flexible electronics

In this study, we developed foldable transparent electrodes composed of Ag nanowire (AgNW) networks welded by Ag nanoparticles (AgNPs) reduced from commercial Ag ink. All the processes used were solution-based. Using the Meyer rod method, uniform AgNW networks were roll-to-roll coated on large-area polymer substrates, and the spin-coated AgNPs firmly welded the AgNWs together at junctions and to substrates. The hybrid films consisting of AgNWs and the Ag film matrix exhibited higher electrical conductivity (5.0–7.3 × 10⁵ S/m) than and equivalent transparency (90–95%) to the AgNW networks. Furthermore, the hybrid films showed significantly better bending stability than AgNW networks. During cyclic bending tests to 10,000 cycles at 5 mm bending radius and even when almost folded with r_b of 1 mm, the resistivity changes were negligible because AgNWs were tightly held and adhered to the substrate by Ag films covering wires, thereby hindering fracturing of AgNWs under tension. Because the films were fabricated at a low temperature, there was no oxidation on the surfaces of the films. Hence, flexible organic light-emitting diodes (f-OLEDs) were successfully fabricated on polyethylene terephthalates (PET) coated with the hybrid films. The f-OLED in the bent state was comparable to that in the flat state, validating the potential applications of these transparent hybrid films as electrodes in various flexible electronics.     

Neutral-pH PEDOT:PSS as over-coating layer for stable silver nanowire flexible transparent conductive films

The silver nanowire (AgNW) mesh film with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the over-coating layer is a promising flexible transparent conductive film technology. In this work, experimental studies show that the hygroscopic and acid properties of the common PEDOT:PSS lead to poor stabilities of the composite films, due to the conductivity degradation of PEDOT:PSS by the water absorption and the acid corrosion of AgNWs by PEDOT:PSS. By using the modified PEDOT:PSS of neutral pH as the over-coating layer, the long term shelf-life time, thermal and current stressing stabilities are all significantly improved without sacrifice of transparency, electrical conductivity and mechanical flexibility. Under both cases of thermal aging test at 210 °C for 20 min and 12 h continuous current stressing at a current density of 30 mA/cm², no obvious change of the conductivity is observed. The results clearly demonstrate that using the neutral-pH PEDOT:PSS as an over-coating layer can help to achieve flexible AgNW transparent conductive films with superior stability for flexible optoelectronic devices.     

Low resistive transparent and flexible ZnO/Ag/ZnO/Ag/WO3 electrode for organic light-emitting diodes

Transparent electrodes cannot easily be created with high transmittance and low sheet resistance simultaneously, although some optoelectronic devices, such as large organic light-emitting diode (OLED) displays and lightings, require very low resistive transparent electrodes. Here, we propose a very low resistive transparent electrode (～1.6 Ω/sq) with a high transmittance (～75%) for OLED devices, the transmittance level of which represents the highest reported value to date given such a low sheet resistance level. It consists of a stacked silver (Ag)/zinc oxide (ZnO)/Ag multilayer covered by high refractive index dielectric layers. The proposed multilayer electrode with optimal layer thicknesses has a high and wide spectral transmittance peak due to interference. The low sheet resistance is a result of two Ag layers connected via the sandwiched ZnO layer. In addition to its low sheet resistance coupled with high transmittance, the proposed multilayer electrode has good flexibility. An OLED with an anode of the stacked Ag/ZnO/Ag multilayer shows performance comparable to that of an anode of indium tin oxide.