Structure–Property Correlation behind the High Mobility of Carbazolocarbazole

Abstract

A comparative study of carbazolocarbazole isomers and their respective N-alkyl derivatives confirms the good performance of carbazolo­[2,1-a]­carbazole as hole-transporting material in organic field effect transistors. The azaphenacene structure of this molecule forms a dense packing promoted by particularly short longitudinal shifts between molecules establishing face-to-face and edge-to-face interactions. Computational calculations have determined an almost isotropic 2D transport environment within a lamellar structure. This favorable solid state arrangement, in combination with appropriate interfacial layers, has led to a high mobility (1.3 cm2 V–1 s–1) that validates the aptitude of this molecular material as an organic semiconductor.

Improving the Robustness of Organic Semiconductors through Hydrogen Bonding

“…Atomic force microscopy (AFM) images revealed that ADAI thin films showed a granular morphology (Figure ). This type of microstructure has been previously correlated to good mobilities for similar molecules . This contrasts with the morphology observed for the material based on ADI that cannot form hydrogen bonds.…”

“…The molecule that cannot self-assemble by hydrogen bonds, i.e ., ADI , crystalizes in a monoclinic cell (space group P 2 1 / m ). It shows a herringbone packing, very common in fused polyheteroaromatic systems with a similar structure (Figure a). , …”

Effect of molecular geometry and extended conjugation on the performance of hydrogen-bonded semiconductors in organic thin-film field-effect transistors

“…77,78 The identical angular catacondensation of NDAI and ADAI shows how the extended conjugation from the naphthalene to the anthracene spacer causes an increase in the HOMO energy of ADAI as previously observed for similar phene-like polyheteroaromatic molecules. 49,51,[79][80][81][82] This effect is also exhibited by the molecule with the larger pyrene spacer, PDAI, whose HOMO has a slightly higher energy. Coincidentally, BDAI and ADAI displayed similar HOMO energies.…”

“…[43][44][45][46][47] The modification of the geometry of fused rings and the study of isomerism has also enabled a better understanding of the structure-property correlation. [48][49][50][51][52] Additionally, the expansion of the p-conjugated surface has been usually employed to modulate the intermolecular interactions. 53,54 In this context, the molecular organisation in p-conjugated systems could be further controlled by virtue of the cooperative effect of stronger non-covalent interactions.…”

Meta‐Stable Molecular Configuration Enables Thermally Stable and Solution Processable Organic Charge Transporting Materials

“…Based on the derived insights, we judiciously designed five ID‐substituted CTMs from perylene diimide derivative (PDI), [ 14 ] tetracene‐5,6:11,12‐bisimide derivative (TBI), [ 15 ] pentacene (Pent), [ 16 ] truxene analogue (Trux), [ 17 ] and carbazolo[4,3‐c]carbazole (Carz), [ 18 ] which are PDI‐ID, TBI‐ID, Pent‐ID, Trux‐ID, and Carz‐ID, respectively (Figure 1). The former two coupled with NDI‐ID are ETMs, while the latter three are HTMs.…”