Systematic Analysis of Self-Assembled Nanodielectric Architecture and Organization Effects on Organic Transistor Switching

Abstract

The unconventional self-assembled nanodielectric (SAND) architecture is composed of solution-processed alternating inorganic (e.g., ZrO x and HfO x ) and π-organic nanolayers (e.g., stilbazolium). As gate dielectrics, SANDs are compatible with a wide variety of organic and inorganic semiconductors and often impart superior thin-film transistor (TFT) performance in comparison to analogous inorganic-only dielectrics. The enhanced performance has been partly attributed to the interactions within the organic layers. To probe the role of the highly polarizable stilbazolium (Chr) organic layer in SAND structural organization and dielectric response, a saturated hydrocarbon chain-based self-assembling building block (Alk) was synthesized and incorporated in SAND structures. By using Chr and Alk in the different SAND organic layers, the effects of the Chr built-in dipole on bulk SAND structural and dielectric characteristics can be evaluated. The Zr-SAND structures are characterized by atomic force microscopy, X-ray reflectivity, metal-insulator-semiconductor electrical measurements, and pentacene-based organic TFTs. The layer identity and arrangement of the organic layers within the Zr-SAND structure are found to have a significant impact on the capacitor leakage current and pentacene transistor threshold voltage/turn-on voltage characteristics. Furthermore, significant cooperative interactions between adjacent Chr organic π-layers are important in enhancing these effects.

Flexible and Stretchable Organic Electrochemical Transistors for Physiological Sensing Devices

“…The ion intake/outtake and the redox process vary the electronic carrier density in the semiconductor modulating the electronic conductivity of the channel upon application of V GS /V DS biases (Figure 1c). [89] Consequently, a volumetric capacitance is associated with OECT operation, which is typically orders of magnitude higher than that in typical OFETs/OEDLTs, [90][91][92][93][94] as well as solution processed metal oxide FETs/EDLTs, [95][96][97][98][99][100][101] leading to a large amplification capability at low driving voltages (typically <1 V for aqueous electrolyte). [42,71] Figure 1d compares the g m range of OFETs, OEDLTs, and OECTs versus driving voltage, but note, the driving voltages of OFETs are typically much larger than the 5 V reported in this figure . The most advanced OECTs reported to date are based on ptype (hole-transporting or electrochemically oxidized) semiconductors, while n-type (electron-transporting or electrochemically reduced)-semiconductor-based OECTs remain rare, are typically less stable, and exhibit much lower performance compared to their p-type counterparts.…”

“…The ion intake/outtake and the redox process vary the electronic carrier density in the semiconductor modulating the electronic conductivity of the channel upon application of V GS / V DS biases (Figure 1c). [ 89 ] Consequently, a volumetric capacitance is associated with OECT operation, which is typically orders of magnitude higher than that in typical OFETs/OEDLTs, [ 90–94 ] as well as solution processed metal oxide FETs/EDLTs, [ 95–101 ] leading to a large amplification capability at low driving voltages (typically <1 V for aqueous electrolyte). [ 42,71 ] Figure 1d compares the g m range of OFETs, OEDLTs, and OECTs versus driving voltage, but note, the driving voltages of OFETs are typically much larger than the 5 V reported in this figure.…”

Self-Assembled Monolayer for Low-Power-Consumption, Long-Term-Stability, and High-Efficiency Quantum Dot Light-Emitting Diodes

“…Self-assembly is the process by which molecules spontaneously assemble to form organized and ordered structures. , Self-assembled monolayers (SAMs) possess highly ordered two-dimensional molecular arrangements on the surface of different kinds of substrates and have been widely adopted in a variety of technologies. , SAM molecules usually contain anchoring groups such as carboxylic acid or phosphonic acid to form covalent links to the substrate, and this ensures SAM’s coverage. , In organic devices, the concept of SAMs has been used on electrodes, semiconductors, and dielectrics to modify their surface properties in order to obtain good charge transport performance through the contacting organic layers. Those organic devices include both electronic and optoelectronic components, such as thin-film transistors, sensors, solar cells, photodetectors, and light-emitting diodes. − The roles of SAMs are to enable tuning of the surface work function, improve interfacial compatibility, and serve as an HTL . In addition to the electrical functionality, SAMs also offer multiple advantages, including tunable band gap, simple processing, large-area application, low material consumption, and green-solvent processes.…”