Diperfluorophenyl Fused Thiophene Semiconductors for n‐Type Organic Thin Film Transistors (OTFTs)

Abstract

Three new fused thiophene semiconductors, end‐capped with diperfluorophenylthien‐2‐yl (DFPT) groups (DFPT‐thieno[2′,3′:4,5]thieno[3,2‐b]thieno[2,3‐d]thiophene (TTA), DFPT‐dithieno[2,3‐b:3′,2′‐d]thiophenes (DTT), and DFPT‐thieno[3,2‐b]thiophene (TT)), are synthesized and characterized in organic thin film transistors. Good environmental stability of the newly developed materials is demonstrated via thermal analysis as well as degradation tests under white light. The molecular structures of all three perfluorophenylthien‐2‐yl end‐functionalized derivatives are determined by single crystal X‐ray diffraction. DFPT‐TTA and DFPT‐TT exhibit good n‐type TFT performance, with mobilities up to 0.43 and 0.33 cm2 V−1 s−1, respectively. These are among the best performing n‐type materials of all fused thiophenes reported to date. The best thin film transistor device performance is achieved via an n‐octadecyltrichlorosilane dielectric surface treatment on the thermally grown Si/SiO2 substrates prior to vapor‐phase semiconductor deposition. Within the DFPT series, carrier mobility magnitudes depend strongly on the semiconductor growth conditions and the gate dielectric surface treatment.

The impact of diperfluorophenyl and thienyl substituents on the electronic structures and charge transport properties of the fused thiophene semiconductors

“…The cationic and anionic geometries are also optimized at the same level. The selected optimized bond lengths, bond angles, and dihedral angles in the neutral and ionic states as well as the experiment crystal data are listed in Supporting Information Tables S2‐S4. It can be seen that the bond lengths and bond angles of the 3 molecules are in good agreement with the corresponding experimental data.…”

“…This is not surprising because the experimental mobility is very sensitive to the experimental conditions (the experimental mobilities are strongly influenced by the microstructural characteristics of the dielectric layers in the device, such as film deposition temperature, film growth mode, and semiconductor phase composition), and the theoretical values are obtained under ideal conditions of perfect crystal at room temperatures. Taking DFPT‐TTA as an example, the tested experimental electron mobility is ranging from 0.0011 to 0.43 cm 2 V −1 s −1 . Despite the difference between the calculated results and experimental data, our calculated mobilities based on the crystal structures could provide the reasonable expectations and help to understand the charge transport property of this kind of material.…”

“…After that, they functionalized tetrathienoacene (TTA) with perfluorophenyl units and obtain n‐type mobility of DFP‐TTA (see Supporting Information Figure S1) as high as 0.30 cm 2 V −1 s −1 . To further enhance the OTFT performance, Youn and co‐workers add additional thiophene rings into the DFP‐TTA skeleton and obtained the electron mobilities of diperfluorophenylthien‐2‐yl (DFPT)‐TTA up to 0.43 cm 2 V −1 s −1 . Comparably, 2 other DFPT‐functionalized fused thiophenes, DFPT‐DTT and DFPT‐thieno[3,2‐ b ]thiophene (TT)), also show excellent electron transport property, with electron mobilities of 0.086 and 0.33 cm 2 V −1 s −1 , respectively.…”

Deformation Effect on the Electrical Properties of a Flexible Organic Semiconductor composed of Poly(dimethylsiloxane) and Multiwalled Carbon Nanotubes

“…[1][2][3][4] Organic semiconductors, such as pentacene and polythiophene, have been widely applied in radio frequency identifi cation tags, electronic papers, and so forth over the past few decades for their fl exible nature, low cost synthetic technology, and structural versatility. [5][6][7][8] Ever evolving be used to construct fl exible electronics such as diodes, transistors, and photodetectors. [ 33,34 ] The performances of the composites can be easily tuned by changing the MWNT loadings, rather than incorporating functionality by molecular design like conventional organic semiconductors.…”

Fused thiophenes: an overview of the computational investigations

“…Their stable and electron rich structures make them important building blocks for the construction of OPVs and OTFTs. 32,33 DTT and its isomers demonstrated various intermolecular interactions including weak hydrogen bonding, π-π stacking, C-H interactions, and S-S interactions. 34 In case of the dimer of the fused thiophene, α,α-bis(dithieno[3,2-b:2',3'-d]thiophene) (BDT) was found to have an unusual π-stacking rendering a high mobility up to 0.05 cm 2 V -1 s -1 .…”