Diselenophene‐Dithioalkylthiophene Based Quinoidal Small Molecules for Ambipolar Organic Field Effect Transistors

Abstract

This work presents a series of novel quinoidal organic semiconductors based on diselenophene‐dithioalkylthiophene (DSpDST) conjugated cores with various side‐chain lengths (‐thiohexyl, ‐thiodecyl, and ‐thiotetradecyl, designated DSpDSTQ‐6, DSpDSTQ‐10, and DSpDSTQ‐14, respectively). The purpose of this research is to develop solution‐processable organic semiconductors using dicyanomethylene end‐capped organic small molecules for organic field effect transistors (OFETs) application. The physical, electrochemical, and electrical properties of these new DSpDSTQs are systematically studied, along with their performance in OFETs and thin film morphologies. Additionally, the molecular structures of DSpDSTQ are determined through density functional theory (DFT) calculations and single‐crystal X‐ray diffraction analysis. The results reveal the presence of intramolecular S (alkyl)···Se (selenophene) interactions, which result in a planar SR‐containing DSpDSTQ core, thereby promoting extended π‐orbital interactions and efficient charge transport in the OFETs. Moreover, the influence of thioalkyl side chain length on surface morphologies and microstructures is investigated. Remarkably, the compound with the shortest thioalkyl chain, DSpDSTQ‐6, demonstrates ambipolar carrier transport with the highest electron and hole mobilities of 0.334 and 0.463 cm2 V−1 s−1, respectively. These findings highlight the excellence of ambipolar characteristics of solution‐processable OFETs based on DSpDSTQs even under ambient conditions.

Bicyclopentadithiophene-Based Organic Semiconductor for Stable and High-Performance Perovskite Solar Cells Exceeding 22%

“…The DPV data clearly confirms that the variation in the alkyl chain (branched octyl vs linear octyl) has no significant effect on the electrochemical properties of NFAs, and each pair possesses similar oxidation and reduction potentials. 54,58 In contrast, halogenated compounds 2 and 3 feature more positive oxidation (E ox = +1.23 V) and reduction (E red = −0.28 V) potentials in comparison to their analogue 1 (E ox = +1.17 To investigate the impact of the chemical geometry structure of the six IN X BCDT molecules on passivation ability, DFT calculations were employed at the B3LYP/6-31G* level of the Gaussian 03W program. The computational results indicate that the HOMO is primarily distributed across the central BCDT, whereas the LUMO is situated on the end-group INderivatives or the whole backbone.…”

“…The DPV data clearly confirms that the variation in the alkyl chain (branched octyl vs linear octyl) has no significant effect on the electrochemical properties of NFAs, and each pair possesses similar oxidation and reduction potentials. 54 , 58 In contrast, halogenated compounds 2 and 3 feature more positive oxidation ( E ox = +1.23 V) and reduction ( E red = −0.28 V) potentials in comparison to their analogue 1 ( E ox = +1.17 V, E red = −0.40 V), which leads to lower HOMO (−5.67 eV) and LUMO (−4.16 eV) vs seen with nonhalogenated 1 [HOMO (−5.61 eV) and LUMO (−4.04 eV)]. Due to the electron-deficient nature of the halogenated indanones, compounds 2 and 3 display a shift toward higher values in both oxidation and reduction potentials in comparison to the potentials noticed for 1 .…”