Visualizing transport in thiazole flanked isoindigo-based donor–acceptor polymer field-effect transistors

Abstract

Fluorination of donor-acceptor copolymers has been one strategy towards enhancing polymer coplanarity, increasing crystallinity, and improving charge transport mechanisms in organic devices. Herein, we report on the synthesis of thiazole...

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“…In this way, for the pull-down transistor, we needed to select a material for constructing an n-type FET which has similar operational characteristics to our P1 and P2 devices. We have previously demonstrated n-type behavior in a TGBC architecture for IID-TzSe FETs . For such devices, an average electron mobility of 1.8 × 10 –2 cm 2 /(V s) was demonstrated, with the results from nonlinear optical methods suggesting that mobilities as high as 0.25 cm 2 /(V s) could be achieved if the influences of contact resistance and interfacial trapping were removed .…”

“…Unless otherwise stated, all operations and reactions were carried out under argon using standard Schlenk line techniques. IID-TzSe was synthesized according to the reported procedure . Analytical thin-layer chromatography was performed on Merck aluminum-backed plates precoated with silica (0.2 mm, 60 F254) gel.…”

“…Our prior work demonstrated Se-substituted thiazole-flanked fluorinated IID copolymer (IID-TzSe) to be ambipolar with exclusively n-type transport in TGBC FET architectures. 17 Using IID-TzSe as the n-channel FET, both P1 and P2 FETs show promising gain in inverter circuits. The HOMO and lowest unoccupied molecular orbital (LUMO) (lowest occupied molecular orbital) levels of IID-TzSe better matched with P1 due to which the complementary inverter circuit shows an ideal push−pull-type behavior.…”

“…Being able to tune the electronic and optical properties with electron-rich and electron-deficient units connected through a covalent linkage in donor–acceptor (D–A)-type copolymers has been very attractive for expanding the scope of low-cost electronic devices. − Not only do D–A copolymers help in reducing the optical band gap, which have excellent opportunities in photovoltaics, , having donor and acceptor chromophores in a polymer chain also enables both p-type and n-type transport. , Electron-deficient acceptor units such as benzothiadiazole (BT), benzotriazole (BTr), diketopyrrolopyrrole (DPP), isoindigo (IID), and naphthalenediimide (NDI) have received a lot of interest in organic electronics. DPP-based copolymers have been attractive in organic solar cells, photodetectors, and transistors due to their high carrier mobilities. − Replacing the sulfur atom with other heavier atoms offers a versatile approach for tailoring the electronic properties of materials and enhancing charge transport properties in IID-based copolymers. − NDI-type copolymers show great potential for doping and have found applications in various electronic devices, including thermoelectrics. − …”

“…Notably, the p-type FETs were configured in complementary voltage inverter circuits. Our prior work demonstrated Se-substituted thiazole-flanked fluorinated IID copolymer (IID-TzSe) to be ambipolar with exclusively n-type transport in TGBC FET architectures . Using IID-TzSe as the n-channel FET, both P1 and P2 FETs show promising gain in inverter circuits.…”