Albeltagi Ahmed, Gallegos-Rosas Katherine, Soldano Caterina
Department of Physics and Mathematics, Institute of Photonics, University of Eastern Finland, 80100 Joensuu, Finland.
Department of Electronics and Nanoengineering, School of Electrical Engineering, Aalto University, 02150 Espoo, Finland.
Materials (Basel). 2021 Dec 11;14(24):7635. doi: 10.3390/ma14247635.
Organic light emitting transistors (OLETs) combine, in the same device, the function of an electrical switch with the capability of generating light under appropriate bias conditions. In this work, we demonstrate how engineering the dielectric layer based on high- polyvinylidene fluoride (PVDF)-based polymers can lead to a drastic reduction of device driving voltages and the improvement of its optoelectronic properties. We first investigated the morphology and the dielectric response of these polymer dielectrics in terms of polymer (P(VDF-TrFE) and P(VDF-TrFE-CFE)) and solvent content (cyclopentanone, methylethylketone). Implementing these high- PVDF-based dielectrics enabled low-bias ambipolar organic light emitting transistors, with reduced threshold voltages (<20 V) and enhanced light output (compared to conventional polymer reference), along with an overall improvement of the device efficiency. Further, we preliminary transferred these fluorinated high- dielectric films onto a plastic substrate to enable flexible light emitting transistors. These findings hold potential for broader exploitation of the OLET platform, where the device can now be driven by commercially available electronics, thus enabling flexible low-bias organic electronic devices.
有机发光晶体管（OLET）在同一器件中兼具电开关功能以及在适当偏置条件下发光的能力。在这项工作中，我们展示了基于高聚偏二氟乙烯（PVDF）的聚合物对介电层进行工程设计如何能够大幅降低器件驱动电压并改善其光电性能。我们首先从聚合物（聚（偏二氟乙烯 - 三氟乙烯）和聚（偏二氟乙烯 - 三氟乙烯 - 氯氟乙烯））以及溶剂含量（环戊酮、甲乙酮）方面研究了这些聚合物介电材料的形态和介电响应。采用这些基于高PVDF的介电材料能够实现低偏置双极性有机发光晶体管，其阈值电压降低（<20 V）且光输出增强（与传统聚合物参考器件相比），同时器件效率整体得到提高。此外，我们初步将这些氟化高介电薄膜转移到塑料基板上以实现柔性发光晶体管。这些发现为更广泛地开发OLET平台具有潜力，在该平台中，器件现在可以由商用电子设备驱动，从而实现柔性低偏置有机电子器件。
