Air‐Stable n‐Type Organic Field‐Effect Transistors Based on Carbonyl‐Bridged Bithiazole Derivatives

Abstract

An electronegative conjugated compound composed of a newly designed carbonyl‐bridged bithiazole unit and trifluoroacetyl terminal groups is synthesized as a candidate for air‐stable n‐type organic field‐effect transistor (OFET) materials. Cyclic voltammetry measurements reveal that carbonyl‐bridging contributes both to lowering the lowest unoccupied molecular orbital energy level and to stabilizing the anionic species. X‐ray crystallographic analysis of the compound shows a planar molecular geometry and a dense molecular packing, which is advantageous to electron transport. Through these appropriate electrochemical properties and structures for n‐type semiconductor materials, OFET devices based on this compound show electron mobilities as high as 0.06 cm2 V−1 s−1 with on/off ratios of 106 and threshold voltages of 20 V under vacuum conditions. Furthermore, these devices show the same order of electron mobility under ambient conditions.

Understanding electron-withdrawing substituent effect on structural, electronic and charge transport properties of perylene bisimide derivatives

“…In the complementary circuits both p-type and n-type organic materials are required, performing with high operating speed but low power consumption [14,15]. It is desirable to search for the practical n-type and ambipolar materials with high mobility and air stability [16,17].…”

Density functional theory study on electron and hole transport properties of organic pentacene derivatives with electron‐withdrawing substituent

“…It is only in the past decade that n-type materials have begun to attract researchers' interest and some promising organic electronegative conjugated compounds have been put forward subsequently. [24][25][26][27][28][29][30][31] Attaching electron-withdrawing substituents such as CN, Br, and F to the p-conjugated ring or functionalizing the conjugated cores can lower the molecular orbital energy level and provide stronger electron affinities, which will facilitate the injection of electrons. Pentacene, as one of the most widely studied organic semiconductors, exhibits satisfying p-type properties with superior charge mobility.…”

Trends in molecular design strategies for ambient stable n-channel organic field effect transistors

“…The air stable n-channel OSC 5e was developed by inserting benzo [1,2- When a carbonyl group is used to bridge the two thiazole moieties as in compound 5g, the LUMO energy level stabilized significantly from À3.17 to À3.64 eV. 247 Introducing nitrogen into thiophene rings and employing carbonyl bridges increases EAs and therefore the stability of the n-doped state. The gain in electron affinity improves the n-channel charge carrier mobility of 5g.…”