Insight into the diindolo[3,2-b:2′,3′-h]carbazole core as an air-stable semiconductor for OTFTs

Abstract

Encouraged by the outstanding performance of pentacene, the perspective over enhanced organic semiconductors has been focused on studying analogous ladder-type materials. In this context, the case of the diindolo[3,2-b:2′,3′-h]carbazole core is a promising example of a semiconductor with improved stability. Herein, we report the synthesis of five diindolo[3,2-b:2′,3′-h]carbazole derivatives displaying different alkylation patterning, as well as their integration in organic thin-film transistors. The elucidation of the single-crystal structures of three of the derivatives, accomplished by means of powder X-ray diffraction (PXRD), provided further insight into the intermolecular disposition of this core. As a result, the relationship between the structural design and the performance of the final devices could be analyzed. Globally, a scope of mobility values from 10–6 to 10–3 cm2 V–1 s–1 was achieved by just fine-tuning the length of the alkyl chains and the type of passivation layer applied onto the SiO2 surface. Remarkably, all the fabricated devices excel in terms of temporal and air stability with a shelf lifetime up to years, a coveted feature in organic electronics that confirms the potential of this core.