Towards a Transparent,Highly Conductive Poly(3,4‐ethylenedioxythiophene)

A detailed investigation of the processing parameters influencing the oxidative polymerization of 3,4‐ethylenedioxythiophene (EDOT) and a methanol‐substituted derivative (EDOT–CH₂OH) was performed with the goal of maximizing the conductivity of the polymer. We show that the conductivity can be significantly enhanced by varying the monomer, oxidant (iron(III ) p‐toluenesulfonate (Fe(OTs)₃)), weak base (imidazole (Im)), solvent (various alcohols), and solution concentrations. The effect of each variable on the final materials properties is investigated, and the parameters have been optimized to achieve conductivities as high as 900 S cm^–1. Surface resistance below 150 Ω/□ for 80–90 nm thick films with visible‐spectrum transparency exceeding 80 % is achieved. The combination of these properties makes the films highly suitable for numerous device applications.     

Transparent and flexible amorphous InZnAlO films grown by roll-to-roll sputtering for acidic buffer-free flexible organic solar cells

We report on transparent and flexible amorphous In–Zn–Al–O (a-IZAO) films prepared by roll-to-roll (RTR) sputtering for use as anodes in acidic buffer free flexible organic solar cells (FOSCs). The presence of Zn and Al structural stabilizers in the In₂O₃ matrix produced a completely amorphous structure with the high optical transmittance of 89.25% and the low resistivity of 2.123 × 10⁻³ Ω-cm, as well as the high work function of 5.14 eV, making the a-IZAO films suitable for use as flexible anodes for FOSCs. In addition, the a-IZAO films showed no change in resistance (ΔR) during outer and inner bending fatigue tests due to their good mechanical flexibility. Relative to the power conversion efficiency (1.944%) of a PEDOT:PSS-based FOSCs, a FOSC fabricated by using an a-IZAO anode and without the use of acidic PEDOT:PSS buffer showed greater power conversion efficiency (2.509%), owing to the absence of interfacial reactions between the acidic PEDOT:PSS and the a-IZAO anode.     

Effects of the ink concentration on multi-layer gravure-printed PEDOT:PSS

To date, highly conductive PEDOT:PSS is the most promising transparent electrode for printing-based flexible organic electronics. Spin-coating and slot-die coating have been commonly used for printing this material. Among the roll-to-roll printing processes, gravure is the most promising for manufacturing large area electronics offering the advantages of high speed and high printing definition. However, gravure printing highly conductive PEDOT encounters some technological limitations such as low thickness, layer inhomogeneity and high surface roughness resulting in a layer not suitable as electrode in electronic devices. In order to realize an electrode of highly conductive PEDOT by gravure printing, a multilayer approach with variable ink concentration was tried using IPA as process solvent. Variable solvent amount of overlapped printed layers was found to play an important role in the spreading of the PEDOT ink onto the pre-printed layers and in the smoothing of its existent peaks. In particular, adopting increasing ink dilution with increasing of the overlapped layers, multi-layer gravure-printed highly conductive PEDOT was successfully realized with characteristics suitable as transparent electrode for organic electronic devices (sheet resistance lower than 130 Ω/sq, conductivity higher than 450 S/cm and optical transmittance over 80%). This is the first time that such results were reached by gravure printing technique thanks to the easy proposed approach.     

有机溶剂对PVA/PEDOT:PSS导电纤维性能和结构的影响

采用湿纺工艺成功制备了聚(3,4-乙撑二氧噻吩)-聚(苯乙烯磺酸)(PEDOT:PSS)和聚乙烯醇(PVA)导电纤维,选用不同有机溶剂如乙二醇(EG)、二甲基亚砜(DMSO)、N,N-二甲基甲酰胺(DMF)、丙酮对导电纤维进行掺杂,以改善其性能。探究掺杂溶剂对PVA/PEDOT:PSS导电纤维结构和性能的影响。结果表明,掺杂EG的导电纤维表现出良好的导电性,电阻率由4.7×107Ω·cm下降到3.2×105Ω·cm;拉伸强度升高到(34.0±0.5)MPa,断裂伸长率升高至25.9%;表面沟槽和凹陷数量减少,较为光滑。     

A hybrid material of graphene and poly (3,4-ethyldioxythiophene) with high conductivity, flexibility, and transparency

A novel hybrid material prepared from graphene and poly (3,4-ethyldioxythiophene) (PEDOT) shows excellent transparency, electrical conductivity, and good flexibility, together with high thermal stability and is easily processed in both water and organic solvents. Conductivities of the order of 0.2 S/cm and light transmittance of greater than 80% in the 400–1800 nm wavelength range were observed for films with thickness of tens of nm. Practical applications in a variety of optoelectronic devices are thus expected for this transparent and flexible conducting graphene-based hybrid material. Electronic Supplementary Material  Supplementary material is available in the online version of this article at http://dx.doi.org/ and is accessible free of charge.     

聚(3,4-亚乙基二氧噻吩)/聚(苯乙烯磺酸盐)高导电柔性薄膜制备及掺杂效应研究

目的 针对聚(3,4-亚乙基二氧噻吩)/聚(苯乙烯磺酸盐)(PEDOT:PSS)薄膜的电导率低的问题,采用二次掺杂方法,提高薄膜电导率和品质因数(FoM),为制备可打印导电薄膜以及柔性光电器件表面导电层提供技术支撑。方法 采用多种无机酸分别与PEDOT:PSS溶液共混的掺杂方法,通过旋涂法在基底上制备透明导电薄膜。利用四点探针法、分光光度计测试系统,对掺杂处理后薄膜的方块电阻、透光率、导电率和品质因数进行测试及分析。利用原子力显微镜(AFM)、X射线光电子能谱(XPS)和霍尔效应测试系统,对薄膜内部结构进行有理分析,总结提升薄膜电导率的原因。结果 无机酸对薄膜电导率具有提升作用,通过硫酸的掺杂作用后,电导率可以由0.9 S/cm提高到2 216 S/cm,FoM从0.03提高到33;通过焦磷酸掺杂处理后的薄膜,电导率可以提高到1 623 S/cm,FoM提高到40。结论 掺杂试剂的沸点、解离常数、退火温度以及共混液的黏度都会影响薄膜的光电性能。解离常数越低,更容易解离出氢离子的掺杂试剂,能够与PSS结合形成PSSH,促进PEDOT和PSS分离。沸点低和解离常数小的无机酸掺杂试剂,能够有效提高薄膜的电导率,并能够获得高品质因数的薄膜。PEDOT:PSS通过无机酸改性处理后,减小了PEDOT和PSS之间作用力的同时,提高了薄膜内部PEDOT的相对含量,使PEDOT链变得线性,促进载流子传输,从而使薄膜的电导率提高。     

碳钢表面导电PEDOT涂层的电化学制备及防腐性能

目的 在Q235钢基底上电沉积致密导电聚合物PEDOT涂层,利用PEDOT的良好导电性,避免电荷集中,提高Q235钢的防腐性能。方法 在十二烷基硫酸钠（SDS）和高氯酸锂（LiClO4）溶液中,通过电化学恒电流方法在Q235碳钢基底上电聚合EDOT。采用循环极化、开路电位监测（OCP）、电化学阻抗谱（EIS）及扫描振动电极（SVET）等手段,研究导电PEDOT涂层与碳钢基底的电化学交互作用及其对基底腐蚀行为的影响规律。结果 在电流密度为5 mA/cm2的条件下,沉积的PEDOT涂层最完整、致密,具有球状团聚表面形貌。PEDOT/Q235电极在3.5%NaCl溶液中浸泡40 h后电偶电流密度为-15 μA/cm2,电偶电压为-715 mV。多次循环极化曲线基本重合,体现出良好的电化学稳定性。开路电位和EIS结果表明,PEDOT涂层4 d后钝化了基底,对基底产生保护。SVET结果证明,PEDOT涂层能够形成电子离域,避免电荷集中,涂层划痕区的电流密度从628 μA/cm2降低到23.8 μA/cm2。结论 PEDOT涂层可以减轻Q235基底在NaCl溶液中的腐蚀,其减缓腐蚀的能力归因于其结构致密、钝化基底及减少表面电荷集中。     

二元溶剂掺杂的PEDOT/PSS在纸上的导电性研究

目的 提高纸张基底上有机材料的导电性。方法 以有机半导体材料聚3,4-乙撑二氧噻吩/聚苯乙烯磺酸盐（PEDOT/PSS）为导电材料,以不同纸张（硫酸纸、胶版纸、复印纸和喷墨打印纸）做基底,利用二甲基亚砜（DMSO）、异丙醇（IPA）二元溶剂掺杂PEDOT/PSS溶液,对比分析PEDOT/PSS涂层在纸张上的导电性能,同时探讨多层单一浓度、多层降浓度、多层升浓度涂布对涂层导电性能的影响。结果 在PEDOT/PSS溶液中掺杂单一溶剂DMSO,添加DMSO体积分数为5%时,可以得到最佳的导电性能;通过二元溶剂掺杂优化PEDOT/PSS溶液在纸上的成膜,最佳体积分数为23%;同时在不同浓度配方下,喷墨打印纸的涂层导电性能最好;多层降浓度涂布可以将涂层方阻由13 kΩ/□降为0.255 kΩ/□。结论 利用二元溶剂掺杂能够在很大程度上提高了PEDOT/PSS导电涂层的导电性能;表面致密、平滑及透气性低的纸张是最佳的基底选择;多层降浓度涂布是最佳方式。