Angular-Shaped Naphthalene Bis(1,5-diamide-2,6-diylidene)malononitrile for High-Performance, Air-Stable N-Type Organic Field-Effect Transistors

Abstract

The synthesis, characterization, and application of two angular-shaped naphthalene bis(1,5-diamide-2,6-diylidene)malononitriles (NBAMs) as high-performance air-stable n-type organic field effect transistor (OFET) materials are reported. NBAM derivatives exhibit deep lowest-unoccupied molecular orbital (LUMO) levels, suitable for air-stable n-type OFETs. The OFET device based on NBAM-EH fabricated by vapor deposition exhibits a maximum electron mobility of 0.63 cm V s in air with an on/off current ratio ( I/ I) of 10.

Ester-Flanked π-Extended Quinolines for Solution-Processable Ambipolar Organic Field-Effect Transistors

“…Several attempts have been made to enhance the stability and charge-transporting properties of the active semiconducting layer. Good results have been reported with polymer-based devices, but recently, small molecules − are being explored as a competitive alternative to the conjugated polymer owing to their diverse merits of easier synthesis, functionalization, high purity, well-defined structure, and monodisperse molecular weight, which enable large-scale vapor and solution-based fabrication. − Ambipolar small molecules are in high demand because they provide great potential to meet the application requirements such as high functionality, low power consumption, and robustness …”

n-Type Organic Field-Effect Transistors Based on Bisthienoisatin Derivatives

“…Many of n-type OSCs are still unstable when operated in air; this is ascribed to the lowest unoccupied molecular orbital (LUMO) levels which are not sufficiently low . Therefore, enormous efforts have been dedicated to develop air-stable n-type OSCs. , Among n-type OSCs, diketopyrrolopyrrole, , naphthalene diimide, − benzothiadiazole, , and isoindigo are representative units used not only in acceptor parts of donor–acceptor polymers but also in small-molecule semiconductors. − Like these units, introduction of strong electron-withdrawing groups, such as carbonyl groups, − ,− diimide groups, − thiadiazole groups, , and cyano groups, − is an effective approach for designing novel n-type OSCs.…”

“…Bisisatin (Scheme ) is a synthetic precursor of bisisoindigo and also a promising n-type organic material due to the planar framework with four electron-withdrawing carbonyl groups. Moreover, when the β-position carbonyl group is modified by a dicyanomethylene group, we can further lower the LUMO levels to obtain potentially air-stable n-type materials. − To date, two types of bisisatin derivatives have been reported: one has a fused ring system with naphthalene core (Scheme a), and another is bridged by a central single bond (Scheme b) . However, the latter takes a nonplanar structure twisted around the central single bond when the β-carbonyl groups are replaced with dicyanomethylene groups similarly to Scheme d, and this nonplanar framework is not preferable for OFET devices.…”

Benzodipyrrole-2,6-dione-3,7-diylidenedimalononitrile Derivatives for Air-Stable n-Type Organic Field-Effect Transistors: Critical Role of N-Alkyl Substituent on Device Performance

“…Air-stable n ‑type OFET materials must generally have high electron affinity (EA), preventing common redox reactions of water and oxygen that can occur during device operation, causing degradation. Incorporating strong electron-withdrawing substituents such as dicarboxylic imides onto rylenes and cyanos onto quinoidal oligothiophenes and diketopyrrolopyrrole derivatives − has been proved to be an effective strategy for lowering LUMO energy levels and strengthening intermolecular π–π interaction, supporting the realization of air-stable n -type OFETs.…”

“…Previous studies have demonstrated that n ‑type OFETs that are based on this core have promising electron mobilities under ambient conditions . Recently, dicyanomethylene-substituted compounds have attracted much interest as n ‑type OSCs because of the superior electron-withdrawing characteristics of their cyanovinyl groups, which stabilize their LUMO levels . Certain dicyanomethylene-substituted quinoidal OSCs have shown very promising performance in OFET devices.…”