Enhanced electron mobility in crystalline thionated naphthalene diimides

Abstract

A series of five thionated naphthalene diimides (NDIs) with linear alkyl chains was synthesized and the optoelectronic, self-assembly, and device properties were studied. When tested in organic thin-film transistors, the electron mobilities of the thionated derivatives are three orders of magnitude higher than the non-thionated parent analogue, with the highest mobility measured for cis-S2 (µ max = 7.5 × 10 -2 cm 2 V -1 s -1 ). In contrast to branched chain PDIs and NDIs, the electron mobility does not increase appreciably with degree of thionation, and the average mobilities are quite consistent ranging from 3.9 × 10 -2 to 7.4 × 10 -2 cm 2 V -1 s -1 for one to three sulfurs.18 been previously reported for the compound. 37 This discrepancy may be due to slight differences in device configuration and fabrication conditions, or in compound purity. The S3 device annealed at 150 o C also showed no performance, possibly due to the lower thermal stability of the higher thionated compounds (vide supra). Devices could not be prepared from trans-S2 or S4 due to their poor solubility and film-forming ability.

Thionated perylene diimides with intense absorbance in the near-IR

“…15 However, in 2014 in an elegant study Seferos et al discovered that the reaction of PDIs with Lawesson's Reagent resulted in the substitution of the carbonyl oxygens with sulfur to give tetra-thionated PDIs, 16 a strategy that was also employed with naphthalene diimides. 17 It was found that subsequent substitutions resulted in a progressive bathochromic shift in the absorption maxima from 525 nm for the unfunctionalised N,N'-di(3-hexylundecyl)-perylene-3,4:9,10-tetracarboxylic diimide A to 704 nm for the tetra-thionated analogue B. The bathochromic shift in absorbance is accompanied by a shift to more positive potentials for reduction processes.…”

Thionation Enhances the Performance of Polymeric Dopant‐Free Hole‐Transporting Materials for Perovskite Solar Cells

“…Thionation is a straightforward oxygen–sulfur atomic substitution that remarkably tunes the material's optical and electronic properties without the need to synthesize a new compound from scratch but via a simple and single‐step reaction . Seferos and coworkers demonstrated that perylene diimide small molecules display enhanced charge transport characteristics upon thionation, because of the change in their morphological and photophysical properties .…”

Drastic Improvement of Air Stability in an n-Type Doped Naphthalene-Diimide Polymer by Thionation

“…Generally, it is assumed that ambient stability of n-type conductivity can be achieved using materials with a LUMO energy level more negative than −3.9 eV. [42][43][44][45][46] The lowering of the LUMO energy of the semiconductor can be obtained by diverse modifications of the electron withdrawing cores such as in naphthalene diimide (NDI) based co-polymers, one of the most studied class of n-type materials [47][48][49][50][51][52][53][54][55] With the core positions being partially blocked in PNDIT2 by the comonomer, the strategy of lowering the LUMO by replacing the imide group by a mono-thioimide group, known as thionation, appears highly suitable for the development of stable n-doped small molecule NDIs [56][57][58][59] and NDI-based polymers. 60,61 Here we make use of thionated PNDIT2, referred to as 2S-trans-PNDIT2 ( Figure 1b) in which two carbonyl oxygens are substituted by sulphur with full trans-regioselectivity.…”