N,N′-Bis(2-cyclohexylethyl)naphtho[2,3-b:6,7-b′]dithiophene Diimides: Effects of Substituents

Abstract

Naphtho[2,3-b:6,7-b 1 ]dithiophene-4,5,9,10-tetracarboxylic diimide (NDTI) is a promising electron-deficient building block for n-type organic conductors, and the performance of NDTI-based field-effect transistors (FETs) is largely dependent on the substituents that alter the supramolecular organization in the solid state and, in turn, the intermolecular orbital overlap. For this reason, the rational selection of substituent on imide nitrogen atoms and/or thiophene α-positions is the key to developing superior n-type organic semiconductors. We here report new NDTI derivatives having N-(2-cyclohexylethyl) groups. Despite their one-dimensional packing structures in the solid state regardless of the presence or absence of chlorine groups at the thiophene α-positions, their FETs show promising performance with electron mobilities higher than 0.1 cm 2¨V´1¨s´1 under ambient conditions. We also discuss how the cyclohexylethyl groups affect the packing structure in comparison with analogous n-octyl derivatives having the same number of carbon atoms.

Naphthodithiophenediimide–Benzobisthiadiazole-Based Polymers: Versatile n-Type Materials for Field-Effect Transistors and Thermoelectric Devices

“…Polymers with energy levels of the lowest unoccupied molecular orbital ( E LUMO ) lower than −4.0 eV are potential candidates for the development of versatile n-type semiconducting polymers . To realize such low-lying E LUMO , employing or combining π-building block(s) with high electron deficiency in the polymer backbone is a promising strategy. − In this context, naphtho­[2,3- b :6,7- b ′]­dithiophenediimide (NDTI) − and benzo­[1,2- c :4,5- c ′]­bis­[1,2,5]­thiadiazole (BBT) , are among the most electron-deficient building blocks capable of being incorporated into a conjugated polymer backbone. By combining these two building blocks, new polymers PNDTI-BBT-DT and PNDTI-BBT-DP, which have different solubilizing alkyl chains, were designed and synthesized (Figure ).…”

Solvent‐Free Synthesis of Core‐Functionalised Naphthalene Diimides by Using a Vibratory Ball Mill: Suzuki, Sonogashira and Buchwald–Hartwig Reactions

“…Here, we have initiated a research programme to synthesise core‐functionalised naphthalene diimide species (c‐NDIs) which have well established applications in organic electronics, [22] solar cell technology [23] and artificial photosynthesis [24] . In each of these applications, core functionalisation [25] is the key synthetic step in order to tune the electronic properties of the resulting molecules, by the manipulation of the energy levels of the conjugated system. This is especially important because unsubstituted NDIs show relatively limited absorption in the visible region, which make them unattractive candidates for use in organic electronics.…”