Filterless Wavelength-Selective Printed Organic Photodiodes: Correlating Ink Engineering to Device Performance and Functionality.

有机半导体将光电性能的综合可调整性与可伸缩打印技术从溶液中制造的能力结合在一起。这种协同效应使有机光电二极管(OPD)成为近年来最有前途的光检测技术之一。然而，到目前为止，处理和设备性能之间的复杂关联强烈地限制了OPD发挥其潜力。特别是，由于最常见的有机体相异质结(BHJ)材料系统带来的内在挑战，依赖于参数灵活性的功能，如颜色选择性检测，是落后的。在这样的BHJ-系统中，器件光谱范围主要由聚合物给体的吸收决定。相反，由于它的聚合性，它在很大程度上也决定了油墨的粘弹性性质。这种相互依赖对印刷OPD的油墨开发和光谱灵活性造成了瓶颈。在拟议的项目中，我们将研究一种新开发的概念的潜力，通过解决墨水的粘弹性属性与设备的光谱响应性的分离问题，降低制造复杂性并获得更多机会来调整设备的光谱响应性，从而克服这一挑战。这是通过聚焦于“被动”聚合物供体(或受体)(即，理想情况下不对光电流有贡献)来定义油墨流变性，并结合决定设备光谱响应性的合适的小分子受体(或供体)材料来实现。在前期工作取得成功的基础上，我们将选择太阳光收集范围以外的有机材料体系来制作具有高效率、大光谱灵活性和低印刷复杂性的无滤光片波长选择性OPD。为了彻底了解其潜在的机制，OPD的制造将得到先进的光谱和形态研究的补充。由此产生的技术诀窍将极大地有助于理解印刷工艺、多层体系结构和设备物理之间的复杂关联。我们相信，我们的方法与数字印刷技术的使用相结合，将使开发的OPD无缝集成到多设备光学检测系统中。

Organic semiconductors combine synthetic tunability of optoelectronic properties with the ability of fabrication from solution with scalable printing techniques. This synergy has made organic photodiodes (OPDs) one of the most promising photodetection technologies in recent years. However, the complex correlations between processing and device performance has so far strongly limited OPDs to live up to their potential. Particularly, functionalities that rely on parameter flexibility, like color selective detection, are lacking behind due to intrinsic challenges resulting from the most common organic bulk-heterojunction (BHJ) material systems. In such BHJ-systems the device spectral range is mainly governed by the absorption of a polymer donor. Conversely, due to its polymeric nature, it also dictates to a great extent the viscoelastic properties of the ink. This interdependence creates a bottleneck for the ink development and spectral flexibility of printed OPDs. In the proposed project, we will investigate the potential of a newly developed concept that overcomes this challenge, by addressing the decoupling of the viscoelastic properties of the ink from the spectral responsivity of the device, lowering fabrication complexity and gaining greater access to the tuning of device spectral responsivity. This is realized by focussing on “passive” polymer donors (or acceptors) (i.e. ideally not contributing to the photocurrent) to define the ink rheology in combination with suitable small-molecule acceptor (or donor) materials which dictate the spectral responsivity of the device. Based on our sucesfull preliminary work, we will select organic material systems outside the scope of sun-light harvesting for fabrication of filterless wavelength-selective OPDs offering high efficiency, large spectral flexibility and low printing complexity. To provide a thorough understanding of the underlying mechanisms, the OPD fabrication will be complemented by advanced spectroscopical and morphological investigations. The resulting know-how will greatly contribute to the understanding of the complex correlations between printing processes, multilayer architectures and device physics. We believe that our approach combined with the use of digital printing techniques, will enable the seamless integration of the developed OPDs into multidevice optical detection systems.