A High‐k Fluorinated P(VDF‐TrFE)‐g‐PMMA Gate Dielectric for High‐Performance Flexible Field‐Effect Transistors

Abstract

A newly synthesized high-k polymeric insulator for use as gate dielectric layer for organic field-effect transistors (OFETs) obtained by grafting poly(methyl methacrylate) (PMMA) in poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) via atom transfer radical polymerization transfer is reported. This material design concept intents to tune the electrical properties of the gate insulating layer (capacitance, leakage current, breakdown voltage, and operational stability) of the high-k fluorinated polymer dielectric without a large increase in operating voltage by incorporating an amorphous PMMA as an insulator. alt-5,5′-(2,2′-bithiophene)) are demonstrated here. DPPT-TT OFETs with P(VDF-TrFE)-g-PMMA gate dielectrics exhibit a reasonably high field-effect mobility of over 1 cm 2 V −1 s −1 with excellent operational stability. By controlling the grafted PMMA percentage, an optimized P(VDF-TrFE)-g-PMMA with 7 mol% grafted PMMA showing reasonably high capacitance (23-30 nF cm −2 ) with low voltage operation and negligible current hysteresis is achieved. High-performance low-voltage-operated top-gate/bottom-contact OFETs with widely used high mobility polymer semiconductors, poly[[2,5bis(2-octyldodecyl)-2,3,5,6-tetrahydro-3,6-dioxopyrrolo [3,4-c]pyrrole-1,4-diyl]alt-[[2,2′-(2,5-thiophene)bis-thieno(3,2-b)thiophene]-5,5′-diyl]] (DPPT-TT), and poly([N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-

Surface Polarization Doping in Diketopyrrolopyrrole-Based Conjugated Copolymers Using Cross-Linkable Terpolymer Dielectric Layers Containing Fluorinated Functional Units

“…First, the field-effect mobility in the saturation region for more than 10 OFET devices with the 5F-SAPMA dielectrics was calculated to average at 0.305 ± 0.119 cm 2 /(V·s) with a maximum of 0.577 cm 2 /(V·s) for the holes (see Figure S8 in the SI) but could not be calculated for the electrons. The hole mobility was improved from 0.023 to 0.305 cm 2 /(V·s) when changing from the PhAPMA dielectric to the 5F-SAPMA dielectric, consistent with a previous report that found that the field-effect mobility increases when using a fluorine-contained polymer dielectric layer with a lower k in the OFETs. , These results can be interpreted as suppressing the energetic disorder at the interface between the dielectric and polymer semiconductors, which is discussed in the following section. The threshold voltage for hole accumulation dramatically shifts in the positive direction from −20 to −12 V when the PhAPMA dielectrics in the PDPP2T-TT-based OFETs are replaced by the 5F-SAPMA dielectrics.…”

Solution-processable low-voltage carbon nanotube field-effect transistors with high-k relaxor ferroelectric polymer gate insulator

“…The k values were reversely calculated from measured capacitance, and in our experimental condition, the P(VDF-TrFE-CFE) films exhibited k values ranging from 50.1 to 52.4 with slight variation compared to the low-k value of PMMA (=3.84). The calculated k values of each insulating film from the measured capacitances were consistent with those reported in previous studies [40,45,50].…”

Chemically Tunable Organic Dielectric Layer on an Oxide TFT: Poly(p-xylylene) Derivatives

“…Here, mobility is measured as 22.72 (cm 2 V –1 s –1 ), which is a value comparable to those of top reports on the organic gate dielectric TFTs (Table ). − In addition, the same configuration with a PPx-C dielectric layer also presents excellent device performances in both the linear and saturation regions (Figure S8). All of these results indicate that our PPx dielectrics not only are good candidates to replace SiO 2 layers but can also provide several advantages in terms of low-temperature processing, stable throughput, applicability to various type of semiconductora, and controllable thickness.…”