Organozinc Compounds as Effective Dielectric Modification Layers for Polymer Field‐Effect Transistors

Abstract

The interface between the organic semiconductor and dielectric plays an important role in determining the device performance of organic field‐effect transistors (OFETs). Although self‐assembled monolayers (SAMs) made from organosilanes have been widely used for dielectric modification to improve the device performance of OFETs, they suffer from incontinuous and lack uniform coverage of the dielectric layer. Here, it is reported that by introduction of a solution‐processed organozinc compound as a dielectric modification layer between the dielectric and the silane SAM, improved surface morphology and reduced surface polarity can be achieved. The organozinc compound originates from the reaction between diethylzinc and the cyclohexanone solvent, which leads to formation of zinc carboxylates. Being annealed at different temperatures, organozinc compound exists in various forms in the solid films. With organozinc modification, p‐type polymer FETs show a high charge carrier mobility that is about two‐fold larger than a control device that does not contain the organozinc compound, both for devices with a positive threshold voltage and for those with a negative one. After organozinc compound modification, the threshold voltage of polymer FETs can either be altered to approach zero or remain unchanged depending on positive or negative threshold voltage they have.

Construction of cross-linked polymer films covalently attached on silicon substrate via a self-assembled monolayer

“…Self-assembled monolayers are ordered molecular assemblies formed by the chemical adsorption of an active surfactant on a solid surface, which have attracted much attention in the field of chemistry and materials science in the last decade. 22,23 The components that typically make up a self-assembled film are a substrate, most often with a smoothness in the nanometer level, and an anchor group that interacts with the substrate, such as a silane coupling surfactant. Finally, a well-desired structure will assemble (stack, crystallize), with a head group facing outside and providing specificity.…”

Interior-architectured ZnO nanostructure for enhanced electrical conductivity via stepwise fabrication process

“…It is noteworthy that the on-off ratio of the electrical current of flexible devices was ten times greater than rigid devices, owing to the lower current under a dark environment for flexible devices. This can be explained by two reasons which are a good dielectric quality of PI substrate [ 29 ] and an interfacial trap state in polymer (PI) and metal oxide (ZnO nanolines) [ 30 ] uneven thermal distribution and surface characteristics thus trapped electrons, and resultantly lowered current [ 31 ]. For those reasons, the falling time was deteriorated for the array of NB and TA nanolines compared with SiO 2 /Si substrate, but not in the case of NR nanoline, caused by its good electrical characteristics due to high crystalline as shown in Figure 3 and Figure S2 in Additional file 2 .…”

Silk Fibroin for Flexible Electronic Devices

“…[ 142 ] Also, the device showed a low threshold voltage of −0.77 V, which suggests that the P3HT/silk fi broin interface is characterized by low charge trap density, endowing the device with performance comparable with that of P3HT transistors with inorganic dielectrics. [143][144][145] In addition, a p-type α,ω-dihexylquaterthiophene (DH4T) OFET with a silk gate dielectric possessed a mobility of 0.013 cm 2 V −1 s −1 , which is comparable to the mobility value of OFETs with a SiO 2 gate dielectric, but showed a higher switching rate of 10 4 . From this, it can be seen that the ordered structure of the silk biopolymeric substrate provides the possibility for fi broin to be applied as alternative to rigid substrates.…”