High- k Fluoropolymers Dielectrics for Low-Bias Ambipolar Organic Light Emitting Transistors (OLETs)

Ahmed Albeltagi; Katherine Gallegos-Rosas; Caterina Soldano

doi:10.3390/ma14247635

High- k Fluoropolymers Dielectrics for Low-Bias Ambipolar Organic Light Emitting Transistors (OLETs)

Materials (Basel). 2021 Dec 11;14(24):7635. doi: 10.3390/ma14247635.

Authors

Ahmed Albeltagi^{1

2}, Katherine Gallegos-Rosas², Caterina Soldano²

Affiliations

¹ Department of Physics and Mathematics, Institute of Photonics, University of Eastern Finland, 80100 Joensuu, Finland.
² Department of Electronics and Nanoengineering, School of Electrical Engineering, Aalto University, 02150 Espoo, Finland.

Abstract

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-k 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-k 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-k 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.

Keywords: OLET(s); ferroelectric polymer(s); fluoropolymer(s); high-k; low-bias; organic light emitting device(s); organic light emitting transistor(s); polymer gate dielectrics.