Development of Pyrene Derivatives as Promising n‐Type Semiconductors: Synthesis, Structural and Spectral Properties

Abstract

A series of promising candidates for n‐type semiconductors, which were based on a 1,6‐, 1,8‐ and mono‐substituted pyrene‐thiophene backbone with a cyano group and dicyanovinylene moieties, were synthesized. The compounds were characterized using NMR spectroscopy, elemental analysis, UV‐vis, photoluminescence (PL), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), cyclic voltametry (CV) and DFT calculations. The substituent effects on molecular properties were studied in detail. It was found that the dicyanovinylene substitution enhanced the coplanarity of the π‐conjugated systems as compared to cyano substitution. The LUMO energy level was located deeply, and one of them had LUMO of below −4.00 eV, indicating that they may be promising candidates for n‐type semiconductors.

Mono- and di-substituted pyrene-based donor-π-acceptor systems with phenyl and thienyl π-conjugating bridges

“…The absorption and fluorescence emission spectra of the molecules have been analyzed in solvents of increasing polarity. A cursory evaluation of the fluorescence efficiency in THF relatively to diphenyl anthracene shows that all compounds present very low values, in the range of 2-5%, in agreement with recent results on related compounds [20]. Table 3 lists the position of absorption and emission maxima of compounds 1-4 in toluene, THF, DCM and acetone.…”

“…The small anodic wave observed on the reverse scan can be attributed to the re-oxidation of some products of degradation of the irreversible reduction. This marked difference between a reversible oxidation leading to stable cation radicals and the irreversibility of the reduction process suggests that these compounds could be more suitable as p-type organic semiconductors rather than as n-type, as recently proposed [20]. Compounds 1 and 2 with phenyl connecting groups present slightly more positive E pa value than their thienyl counterparts.…”

“…As a first step in the exploration of structure properties relationships in pyrene derivatives designed as potential donor building blocks for single-material organic cells (SMOSCs) [21,22], we report herein on the synthesis and electronic properties of two series of mono-and disubstituted pyrenes in which cyanoester electron acceptor groups are connected to the pyrene core via phenyl and thienyl -conjugating bridges (1-4, Scheme 1). Unlike the already reported compounds [20], the solubility of these new molecules is ensured by the hexyl chains of the cyanoester in order to limit steric hindrance between the thiophene rings and the peripheral hydrogen atoms of pyrene. After screening of their electronic properties, these systems are intended to be connected to non fullerene electron acceptors (NFA) by means of an hydroxyl group which will be fixed at the end of the cyanoalkyl chain according to an already reported approach [23].…”

“…For OPV applications, pyrene has been essentially involved in the synthesis of electron donor materials [14][15][16][17] however, recent work has reported examples of non-fullerene acceptor materials based on a pyrene core [19]. Recently, Gao and coworkers have described potential n-type organic semi-conductors based on mono and disubstituted pyrenes derivatives in which electron acceptor dicyanovinyl groups are connected to the pyrene block by 3-dodecyl-thienyl spacers [20]. The alkyl chains were introduced on the thiophene ring to ensure the solubility of the compounds.…”

Non-K Region Disubstituted Pyrenes (1,3-, 1,6- and 1,8-) by (Hetero)Aryl Groups—Review

“…Introduction of the 3-dodecylthiophen-2-yl units into pyrene at positions 1,6- and 1,8- was described by Deqing Gao et al, where, as a starting material, pure dibromopyrenes were applied and reacted with dodecylthiophene-2-boronic acid pinacol ester using [Pd(PPh 3 ) 4 ] with base Na 2 CO 3 in PhMe/H 2 O solution, which resulted in products with comparable yields 65% and 63% for 1,6-bis(3-dodecylthiophen-2-yl)pyrene 40 and 1,8-bis(3-dodecylthiophen-2-yl)pyrene 41 , respectively (Scheme 24) [21].…”