Solution‐Processable Multifused Thiophene Small Molecules and Conjugated Polymer Semiconducting Blend for Organic Field Effect Transistor Application

Abstract

Three new solution‐processable organic semiconductors (1–3) are synthesized and characterized for p‐type organic field effect transistors (OFETs). The backbone of these small molecules is modified by expanding the central core conjugation from thienothiophene (TT) to dithienothiophene (DTT) and tetrathienoacene (TTA), which are end‐capped with soluble β‐substituted alkyl chains dithienothiophenes (DTTR) to generate DTTR‐TT (1), DTTR‐DTT (2), and DTTR‐TTA (3). The highest mobility of 0.016 cm2 V−1 s−1 is achieved using solution‐sheared DTTR‐TTA film due to the extended conjugated TTA core, which enhances the intermolecular interaction and generates an efficient percolation for the OFET channel. Solution blending of crystalline DTTR‐TT small molecules with oriented‐packing polymer dithienothiophene‐thioalkylbithiophene (PDTT‐SBT) polymer leads to significantly enhanced mobilities from 0.0009 up to 0.22 cm2 V−1 s−1, occurring at an optimized 30% DTTR‐TT composition in the blend. Hole mobility of 30% DTTR‐TT blend is 0.22 cm2 V−1 s−1 which is higher than pristine small molecule DTTR‐TT (0.0009 cm2 V−1 s−1) and polymer PDTT‐SBT (0.067 cm2 V−1 s−1), respectively. An efficient strategy to enhance the mobility of small molecule DTTR‐TT by blending with easily synthesizable PDTT‐SBT polymer is reported.

Fused thiophene based materials for organic thin‐film transistors

“…Furthermore, solution blending of crystalline DTTR‐Ar small molecules (30%) with oriented‐packing polymer dithienothiophene‐thioalkylbithiophene (PDTT‐SBT) polymer leads to significantly enhanced hole mobilities up to 0.22 cm 2 V −1 s −1 . [ 36 ]…”

“…But when alkyl groups are introduced in the DTT unit, 56 shows the mobility of 0.016 cm 2 V −1 s −1 . [ 36 ]…”

Synthesis and Reactivities of Conducting Hexathienylbenzene-Co-Poly(3-Hexylthiophene) Star-Branched Copolymer as Donor Material for Organic Photovoltaic Cell

“…Today, this utilitarian conjugation has driven the development of many conducting polymers such polycarbazoles (Nayana and Kandasubramanian, 2020), polythiophenes (Valderrama-García et al, 2016), polyaniline (Boeva and Sergeyev, 2014) and polynaphthylamine (Pei et al, 2019). Further, conducting polymers have received recognition in such diverse research fields as organic light emitting diodes (Chen et al, 2020), organic field-effect transmitters (Afraj et al, 2021), supercapacitors (Wang et al, 2020), biosensors (Gupta et al, 2020) and OPVs (Liu et al, 2021), amongst others.…”

Solution processable dithioalkylated methylidenyl cyclopentadithiophene based quinoidal small molecules for n-type organic field-effect transistors

“…The intermolecular/intramolecular interactions, molecular packing, and device performances can be significantly affected by the modifications of these alkyl side chains. 13–15 From a molecular design standpoint, the development of donor–acceptor (D–A)-type OSCs with a conjugated backbone has greatly advanced OFET technology, 16 resulting in several high-performance p-type (hole-transporting) 13,17–21 and n-type (electron-transporting) OSC families. 22–30 Despite considerable progress, the performance of n-type semiconductors continues to lag behind that of p-type semiconductors because of the critical requirements for lowest unoccupied molecular orbital (LUMO) energy levels and environmental trapping of electrons.…”