The impact of molecular planarity on electronic devices in thienoisoindigo-based organic semiconductors

Abstract

The influence of molecular planarity on field-effect-transistor and photovoltaic cell performance in thienoisoindigo derivatives has been studied.

Low-Bandgap Near-IR Conjugated Polymers/Molecules for Organic Electronics

“…130 From the film absorption spectra, both absorption bands of S12 and S13 extend to ∼850 nm. From the single-crystal structure analyses of S12 and S13, these two π-frameworks of thienoisoindigobased molecules show high planarity as predicted by the DFT calculation, and form slipped one-dimensional stacks.…”

Design and structure–property relationship of benzothienoisoindigo in organic field effect transistors

“…40 Molecules 1 and 2 exhibited low hole and electron mobilities around 10 À5 -10 À4 cm 2 V À1 s À1 . 28 This p-channel dominant character is because the HOMO level estimated from the CV measurement matches the Fermi level (À5.13 eV) of the Au electrode, 42 therefore, facilitating the effective hole injection from the Au electrodes to the thin lm. These values are comparable or slightly improved compared to the TII-based copolymers 24,31 and the previously reported TII-based small molecules.…”

“…14,15 However, the ambipolar properties of small molecules are still lower than those of polymer semiconductors. 8,[23][24][25][26][27][28][29][30][31][32][33][34][35] In a previous study, we reported ambipolar TII-based small molecules, and these molecules displayed wellbalanced hole and electron mobilities of 10 À2 cm 2 V À1 s À1 in spite of the one-dimensional p-system. [16][17][18][19][20][21] Among the building blocks constituting organic semiconductors, isoindigo (II) is well known as an electron-decient unit realizing a high performance OFET.…”

“…Small molecular semiconductors are considered to be promising ambipolar materials due to their advantages of a well-dened molecular structure, high purity, and less batch-to-batch variations compared to polymer semiconductors. 28 These results prompted us to design a more p-expanded TII-based molecule, benzothienoisoindigo BTII, to ensure strong p-p intermolecular interactions constructing a dense molecular packing preferable for effective charge-transport. 22 II has a slightly twisted structure at the central double bond due to the steric hindrance between the phenyl proton and the carbonyl oxygen.…”

Ultra-narrow bandgap D-A copolymer based on thienoisoindigo acceptor unit for application in polymer solar cells with energy losses below 0.6 eV

“…The TIID-based polymers absorb strongly in the visible and NIR region [15,[18][19][20]. However, the polymers based on TIID were rarely reported in organic photovoltaics (OPVs) [21][22][23][24][25][26][27][28][29][30], due to the high lying highest occupied molecular orbital (HOMO) energy level of TIID-based D-A copolymers, which results in a low V oc in PSCs.…”