Additive-Stabilized Polymer Electronics Manufacturing (ASPEM)

二十多年来，有机半导体一直是重点研究工作的主题。通过研究广泛的共轭聚合物以及分子材料，分子结构与性能的关系已变得详细了解。这导致了材料和器件性能的显著改善：例如，在20世纪90年代中期，有机半导体在晶体管中表现出小于10^-2-10^-3 cm 2/Vs的场效应迁移率，这比工业标准非晶硅晶体管的场效应迁移率低至少两个数量级，其用于液晶显示器应用中并表现出1cm 2/Vs的迁移率。今天，现有技术的有机晶体管对于聚合物达到2- 5cm 2/Vs的迁移率，对于分子系统达到5-15 cm 2/Vs的迁移率。类似地，有机太阳能电池的功率转换效率已经增加到14-15%，这是由于改进材料的可用性，特别是非富勒烯受体的开发。因此，有机半导体和共轭聚合物现在是一种新兴技术，应用范围广泛：有机发光二极管已成为高端智能手机和电视的既定显示技术。聚合物太阳能电池的性能还不能与硅太阳能电池竞争发电应用，但对于室内能量收集，有机太阳能电池已经具有竞争力。基于聚合物的OFFEs已经找到了利基应用，包括柔性电子纸显示器。在过去的两年中，由于更高迁移率材料的商业可用性，大众市场应用的前景有所改善：更先进的显示应用，如LCD显示器，以及非显示应用，如X射线成像和指纹传感，在技术上已经可行，并吸引了大量的工业兴趣和投资。然而，尚未完全解决的技术挑战之一是操作可靠性：尽管取得了重大进展，但可以公平地说，OLED和有机太阳能电池都无法与无机半导体技术相媲美，在许多情况下，无机半导体技术的产品寿命超过5-10年。而且，在延长的操作周期期间，OFFET的阈值电压稳定性劣于氧化物或多晶硅晶体管的阈值电压稳定性，氧化物或多晶硅晶体管在延长的周期上的连续驱动期间表现出小于0.5V的阈值电压偏移。所提出的项目基于最近的技术突破：我们发现，通过向聚合物膜中添加小分子添加剂，可以显著提高最先进的高迁移率聚合物晶体管的操作稳定性（Nikolka等人，Nature Materials 16，356（2017））。我们建议将这种用于添加剂稳定的聚合物（ASP）膜的技术开发成可扩展的制造技术，以满足一系列应用的工业制造要求。我们的ASP技术具有显著提高共轭聚合物的性能和可靠性的潜力，使其能够满足与现有无机半导体类似的可靠性要求。

Organic semiconductors have been the subject of focussed research efforts for more than two decades. By investigating a wide range of conjugated polymers as well as molecular materials, molecular structure-property relationships have become understood in detail. This has resulted in a spectacular improvement in materials and device performance: As an example, in the mid 1990's organic semiconductors exhibited field-effect mobilities in transistors of less than 10^-2-10^-3 cm2/Vs, which were at least two orders of magnitude lower than those of industry standard amorphous silicon transistors, that are used in liquid crystal display applications and exhibit mobilities of 1 cm2/Vs. Today state-of-the-art organic transistors reach mobilities of 2-5 cm2/Vs for polymers and 5-15 cm2/Vs for molecular systems. Similarly, the power conversion efficiency of organic solar cells has increased to 14-15% due to availability of improved materials, in particular the development of non-fullerene acceptors. As a result organic semiconductors and conjugated polymers are now an emerging technology in a broad range of applications: Organic light-emitting diodes have become an established display technology for high-end smart phones and TVs. The performance of polymer solar cells cannot compete yet with silicon solar cells for power generation applications, but for indoor energy harvesting organic solar cells are already competitive. Polymer-based OFETs have found niche applications, including flexible e-paper displays. Over the last two years due to the commercial availability of higher mobility materials the outlook for mass market application has improved: More advanced display applications, such as LCD displays, as well as non-display applications, such as X-ray imaging and fingerprint sensing have become technologically feasible and are attracting serious industrial interest and investment. One of the technology challenges that has, however, not been fully addressed yet is operational reliability: Despite significant progress it would be fair to say that neither OLEDs nor organic solar cells match the impressive reliability of inorganic semiconductor based technologies that in many cases exceed 5-10 years of product lifetime. Also the threshold voltage stability of OFETs during extended periods of operation is inferior to those of oxide or polycrystalline silicon transistors, which exhibit threshold voltage shifts of less than 0.5V during continuous driving over an extended period. The proposed project is based on a recent technology breakthrough: We have discovered that the operational stability of state-of-the-art high mobility polymer transistors can be dramatically increased by addition of a small molecular additive to the polymer film (Nikolka et al., Nature Materials 16, 356 (2017)). We propose to develop this technique for additive-stabilized polymer (ASP) films into a scalable manufacturing technology that meets the requirements for industrial manufacturing across a range of applications. Our ASP technique has the potential of significantly improving the performance and reliability of conjugated polymers to a level where they can meet similarly demanding reliability requirements as achieved with established inorganic semiconductors.