Sawatzki Michael F, Kleemann Hans, Boroujeni Bahman K, Wang Shu-Jen, Vahland Joern, Ellinger Frank, Leo Karl
Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) Technische Universität Dresden Noethnitzer Str. 61 Dresden 01187 Germany.
Chair of Circuit Design and Network Theory (CCN) Technische Universität Dresden Helmholtz Str. 18 Dresden 01069 Germany.
Adv Sci (Weinh). 2021 Jan 27;8(6):2003519. doi: 10.1002/advs.202003519. eCollection 2021 Mar.
Today's organic electronic devices, such as the highly successful OLED displays, are based on disordered films, with carrier mobilities orders of magnitude below those of inorganic semiconductors like silicon or GaAs. For organic devices such as diodes and transistors, higher charge carrier mobilities are paramount to achieve high performance. Organic single crystals have been shown to offer these required high mobilities. However, manufacturing and processing of these crystals are complex, rendering their use outside of laboratory-scale applications negligible. Furthermore, doping cannot be easily integrated into these systems, which is particularly problematic for devices mandating high mobility materials. Here, it is demonstrated for the model system rubrene that highly ordered, doped thin films can be prepared, allowing high-performance organic devices on almost any substrate. Specifically, triclinic rubrene crystals are created by abrupt heating of amorphous layers and can be electrically doped during the epitaxial growth process to achieve hole or electron conduction. Analysis of the space charge limited current in these films reveals record vertical mobilities of 10.3(49) cm V s. To demonstrate the performance of this materials system, monolithic pin-diodes aimed for rectification are built. The of these diodes is over 1 GHz and thus higher than any other organic semiconductor-based device shown so far. It is believed that this work will pave the way for future high-performance organic devices based on highly crystalline thin films.
如今的有机电子器件，比如非常成功的OLED显示器，是基于无序薄膜的，其载流子迁移率比硅或砷化镓等无机半导体的载流子迁移率低几个数量级。对于诸如二极管和晶体管之类的有机器件而言，更高的电荷载流子迁移率对于实现高性能至关重要。有机单晶已被证明能提供所需的高迁移率。然而，这些晶体的制造和加工很复杂，这使得它们在实验室规模以外的应用中几乎可以忽略不计。此外，掺杂不容易集成到这些系统中，这对于需要高迁移率材料的器件来说尤其成问题。在此，针对模型体系红荧烯证明，可以制备高度有序的掺杂薄膜，从而在几乎任何衬底上制造高性能的有机器件。具体而言，通过对非晶层进行突然加热来制备三斜晶系的红荧烯晶体，并且可以在外延生长过程中进行电掺杂以实现空穴或电子传导。对这些薄膜中的空间电荷限制电流的分析揭示了创纪录的10.3(49) cm² V⁻¹ s⁻¹ 的垂直迁移率。为了证明这种材料体系的性能，构建了用于整流的单片pin二极管。这些二极管的截止频率超过1 GHz，因此高于迄今为止所展示的任何其他基于有机半导体的器件。人们相信这项工作将为未来基于高度结晶薄膜的高性能有机器件铺平道路。
