Design, synthesis, and photophysical studies of substituted indigo derivatives for p-type organic thin film transistors

Design, synthesis, and photophysical studies of substituted indigo derivatives for p-type organic thin film transistors

Článek WoS

Indigo, a dye with historical significance, is being investigated as an organic semiconductor for use in organic electronic devices. However, indigo and its derivatives exhibit poor solubility during device processing. In this article, we synthesized symmetrical dibromo, diphenyl, and dinaphthalenyl indigo derivatives (compounds InBr (also known as Tyrian purple), InPh, and InNap). For the first time, we show the synthesis of dihaloindigo by direct halogenation of indigo. To enhance solubility during processing, thermo-cleavable tert-butoxycarbonyl (Boc) groups were incorporated. A post-deposition thermal treatment process is then described, enabling the removal of Boc groups and the production of semiconductor films. The synthesized compounds (InBr, InPh, and InNap) have an optical band gap of 1.6-1.8 eV, while the Boc-protected compounds exhibit a band gap of similar to 2.13 eV. Physical vapor-deposited (PVD) compounds showed p-type charge transport in organic field-effect transistors (OFETs) with a hole mobility of up to 2.2 & times; 10(-2) cm(2)V(-1)s(-1). Moreover, the dibromo derivative InBr showed ambipolar charge transport, featuring electron mobility of up to 1.1 & times; 10(-3) cm(2)V(-1)s(-1) in an electron transport-enhancing setup. The compound InNap, contrary to the usual experience, retained the form of a homogenous film even after the thermal treatment.

Indigo, a dye with historical significance, is being investigated as an organic semiconductor for use in organic electronic devices. However, indigo and its derivatives exhibit poor solubility during device processing. In this article, we synthesized symmetrical dibromo, diphenyl, and dinaphthalenyl indigo derivatives (compounds InBr (also known as Tyrian purple), InPh, and InNap). For the first time, we show the synthesis of dihaloindigo by direct halogenation of indigo. To enhance solubility during processing, thermo-cleavable tert-butoxycarbonyl (Boc) groups were incorporated. A post-deposition thermal treatment process is then described, enabling the removal of Boc groups and the production of semiconductor films. The synthesized compounds (InBr, InPh, and InNap) have an optical band gap of 1.6-1.8 eV, while the Boc-protected compounds exhibit a band gap of similar to 2.13 eV. Physical vapor-deposited (PVD) compounds showed p-type charge transport in organic field-effect transistors (OFETs) with a hole mobility of up to 2.2 & times; 10(-2) cm(2)V(-1)s(-1). Moreover, the dibromo derivative InBr showed ambipolar charge transport, featuring electron mobility of up to 1.1 & times; 10(-3) cm(2)V(-1)s(-1) in an electron transport-enhancing setup. The compound InNap, contrary to the usual experience, retained the form of a homogenous film even after the thermal treatment.

Indigo derivatives, Soluble semiconductor pigments, Organic field effect transistor, Tert-butoxycarbonyl (boc) groups, Density functional theory

Indigo derivatives, Soluble semiconductor pigments, Organic field effect transistor, Tert-butoxycarbonyl (boc) groups, Density functional theory

KUMAR, C.; KRATOCHVÍL, M.; SANKE, D.; YUMUSAK, C.; BEZBORUAH, J.; SARICIFTCI, N.; VALA, M.; WEITER, M.; ZADE, S.

01.05.2026

Elsevier

Organic electronics

152

May

Nizozemsko

107392

10

https://doi.org/10.1016/j.orgel.2026.107392