Combined experimental–theoretical NMR study on 2,5‐bis(5‐aryl‐3‐hexylthiophen‐2‐yl)‐thiazolo[5,4‐d]thiazole derivatives for printable electronics

Abstract

Four 2,5-bis(5-aryl-3-hexylthiophen-2-yl)thiazolo[5,4-d]thiazole derivatives have been synthesized and thoroughly characterized. The extended aromatic core of the molecules was designed to enhance the charge transport characteristics, and solubilizing hexyl side chains were introduced on the thiophene subunits to enable possible integration of these semiconducting small molecules in printable electronics. Complete elucidation of the chemical structures by detailed one-dimensional/two-dimensional NMR spectroscopy is described, providing interesting input for chemical shift prediction software as well, because limited experimental data on these types of compounds are currently available. Furthermore, theoretical calculations have assisted experimental observations--giving support for the chemical shift assignment and providing a springboard for future screening and predictions--demonstrating the benefits of a coordinated theoretical-experimental approach.

Charge transfer in the weak driving force limit in blends of MDMO-PPV and dithienylthiazolo[5,4-d]thiazoles towards organic photovoltaics with high VOC

“…A series of highly soluble functionalized 2,5-dithienylthiazolo [5,4-d]thiazoles (DTTzTz) was recently synthesized within one of our groups and these expanded semiconductors were investigated as active materials for solution-processable OFETs. [9][10][11] In the OPV field, a number of low bandgap copolymer structures incorporating TzTz moieties as the electron poor units have very recently appeared in the literature, showing rather high charge-carrier mobilities and power conversion efficiencies. 12,13 At present the most successful organic solar cells are based on the 3-dimensional bulk heterojunction (3D BHJ) approach in which the active layer consists of two interpenetrating networks of an electron donor compound, most often a conjugated polymer, and an electron acceptor, in many cases fullerene derivatives.…”

Electronic structure of positive and negative polarons in functionalized dithienylthiazolo[5,4-d]thiazoles: a combined EPR and DFT study

“…14 DFT calculations revealed that the principal g values depend not only on the nature of the DTTzTz substituents, but are also slightly influenced by the conformer structure. The heterogeneity due to the predicted coexistence of different conformers 12 is not resolved in the experimental spectra, and if present only contributes to the EPR linewidth. Although two EPR signals were found to contribute to the high-field EPR spectra of oxidized Th-DTTzTz (Fig.…”

“…The synthesis of 2,5-bis(4-hexyl-2,2 0 -bithiophene-5-yl)thiazolo [5,4-d]thiazole (Th-DTTzTz) and 4,4 0 -[5,5 0 -(thiazolo [5,4-d]thiazole-2,5-diyl)bis(4-hexylthiophene-5,2-diyl)]dibenzonitrile (4-CN-Ph-DTTzTz) has been reported elsewhere. [11][12][13] MDMO-PPV was obtained from Covion (M w = 716 kg mol À1 , PD = 6.5). Solutions were prepared in chloroform (CHCl 3 , Acros Organics, 99.9%).…”

“…Earlier theoretical work on functionalized DTTzTz derivatives showed that different conformers exist. 12 To test the effect of the conformer structure, the g and hyperfine values of both majority and minority conformers were computed (ESI †). The computed g values of both species are in good agreement with those observed experimentally (Table 1: the average g-value (g iso ) is identical, the deviation between the experimental and theoretical principal values is of the order of 0.001 or less).…”

“…9,10 Recently, one of our groups synthesized a series of highly soluble functionalized 2,5-dithienylthiazolo [5,4-d]thiazoles (DTTzTz) with varying electronic properties depending on the functionalization pattern. 11,12 Bottom contact devices made from Th-DTTzTz (Fig. 1) showed a hole mobility of 1.58 Â 10 À3 cm 2 V À1 s À1 , representing the first significant FET behaviour of TzTz-based small molecules for printable electronics.…”