One‐Step Sixfold Cyanation of Benzothiadiazole Acceptor Units for Air‐Stable High‐Performance n‐Type Organic Field‐Effect Transistors

Abstract

Reported here is a new high electron affinity acceptor end group for organic semiconductors, 2,1,3‐benzothiadiazole‐4,5,6‐tricarbonitrile (TCNBT). An n‐type organic semiconductor with an indacenodithiophene (IDT) core and TCNBT end groups was synthesized by a sixfold nucleophilic substitution with cyanide on a fluorinated precursor, itself prepared by a direct arylation approach. This one‐step chemical modification significantly impacted the molecular properties: the fluorinated precursor, TFBT IDT, a poor ambipolar semiconductor, was converted into TCNBT IDT, a good n‐type semiconductor. The electron‐deficient end group TCNBT dramatically decreased the energy of the highest occupied and lowest unoccupied molecular orbitals (HOMO/LUMO) compared to the fluorinated analogue and improved the molecular orientation when utilized in n‐type organic field‐effect transistors (OFETs). Solution‐processed OFETs based on TCNBT IDT exhibited a charge‐carrier mobility of up to μe≈0.15 cm2 V−1 s−1 with excellent ambient stability for 100 hours, highlighting the benefits of the cyanated end group and the synthetic approach.

Isomerically Pure Oxindole‐Terminated Quinoids for n‐Type Organic Thin‐Film Transistors Enabled by the Chlorination of Quinoidal Core

“…The use of bottom gate/top contact (BG/TC) architecture has previously been found to enhance the performance of small molecule‐based devices [3a] . Thus, we further optimized the device performance by using BG/TC architecture, and the transfer and output characteristics of the BG/TC devices are shown in Figure 5.…”

“…Although many high‐performance p‐type OSCs have been developed, progress on n‐type OSCs has been slow [3] . The development of n‐type OSCs relies strongly on the design and synthesis of molecules with low‐lying LUMOs (lowest unoccupied molecular orbitals), allowing efficient electron injection [2b,c,3a,b,4] . Generally, such molecules can be synthesized from diimide‐functionalized aromatic building blocks, such as naphthalene diimide (NDI), and perylene diimide (PDI), and by functionalizing known p‐type aromatic molecules with electron‐withdrawing substituents, such as F atoms and cyano (CN) groups [3a,b,5] …”

In Situ Doping of the PEDOT Top Electrode for All-Solution-Processed Semitransparent Organic Solar Cells

“…GIWAXS patterns for PEDOT:PSS films on silicon substrates were measured at the 3C beamline at the PAL. The 2-D GIWAXS patterns of F-PEDOT films were analyzed using molecular diffraction modeling and simulation in the same way as in previous literature . See also Supporting Information Note 2 for details.…”

“…The 2-D GIWAXS patterns of F-PEDOT films were analyzed using molecular diffraction modeling and simulation in the same way as in previous literature. 65 See also Supporting Information Note 2 for details.…”