小分子/聚合物半导体共混物是开发高性能有机电子器件的有前途的解决方案。它们能够结合溶液可加工性的简易性,由于聚合物油墨的流变特性可调,由于小分子的高结晶相,具有出色的电荷传输性能。然而,因为电荷注入的问题,到目前为止,只有在ad-hoc设备架构中才能证明如此好的性能,不适合高频应用,其中晶体管尺寸需要缩小。这里,迄今为止报道的性能最好的混合物的成功整合,基于2,7-二辛基[1]苯并噻吩并[3,2-b][1]苯并噻吩(C8-BTBT)和聚(茚并二噻吩-co-苯并噻二唑)(C16IDT-BT),在以沟道和重叠长度等于1.3和1.9μm为特征的OFET中,分别,被证明,在-8V下实现23MHz的过渡频率。两个关键方面允许这样的结果:分子掺杂,导致宽度归一化接触电阻仅为260Ωcm,允许在短沟道器件中保持高达3cm2/(Vs)的表观场效应迁移率,以及高电容电介质堆叠的实现,使工作电压降低低于10V和克服自热问题。这些结果代表了未来开发用于物联网应用的低成本和高速印刷电子产品的基本步骤。
Small molecule/polymer semiconductor blends are promising solutions for the development of high-performing organic electronics. They are able to combine ease in solution processability, thanks to the tunable rheological properties of polymeric inks, with outstanding charge transport properties thanks to high crystalline phases of small molecules. However, because of charge injection issues, so far such good performances are only demonstrated in ad-hoc device architectures, not suited for high-frequency applications, where transistor dimensions require downscaling. Here, the successful integration of the most performing blend reported to date, based on 2,7-dioctyl[1] benzothieno[3,2-b][1]benzothiophene (C8-BTBT) and poly(indacenodithiophene-co-benzothiadiazole) (C16IDT-BT), in OFETs characterized by channel and overlap lengths equal to 1.3 and 1.9 µm, respectively, is demonstrated, enabling a transition frequency of 23 MHz at -8 V. Two key aspects allowed such result: molecular doping, leading to width-normalized contact resistance of only 260 Ωcm, allowing to retain an apparent field-effect mobility as high as 3 cm2/(Vs) in short channel devices, and the implementation of a high capacitance dielectric stack, enabling the reduction of operating voltages below 10 V and the overcoming of self-heating issues. These results represent a fundamental step for the future development of low-cost and high-speed printed electronics for IoT applications.