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A series of new anthracene/pyrene functionalized triarylamine‐based D‐π‐D' semiconductors are demonstrated as p‐channel material for high‐performance OFETs. The introduction of electron‐donating end‐caps and ethynyl styrylene bridged spacers at D‐π‐D' architecture modulated the self‐ordering, electron distribution, and field‐effect mobility. These molecules exhibited high‐lying HOMO of ∼4.8 eV, enabling the hole‐transporting property and reducing the energy barrier for charge injection. Organic field‐effect transistors fabricated on bottom‐gated top‐contact architecture containing pyrene end‐capped triarylamines with tert‐butylphenyl sidearm as active layer displayed high hole mobility of 2.5 cm2/Vs and on/off current ratio of 107, and the threshold voltage of −7 V. The highest performance was supported by the molecular order of the film, planarity, high HOMO, and electron‐donating nature of the end‐capping units, as illustrated by the SEM, XRD, and DFT studies. [ABSTRACT FROM AUTHOR]

Phenanthro[9,10‐d]imidazole is synthesized by employing Radziszewski method and further functionalized through palladium catalyzed Suzuki cross‐coupling reaction. Solution processable organic field‐effect transistors (OFETs) are assembled in bottom gate‐top contact architecture. A binary solvent system comprising of chloroform/toluene in the ratio of 1/1 is preferred for the deposition of active semiconducting layer. The fabricated devices demonstrated excellent p‐type characteristics with a good mobility, high ON/OFF ratio of 109 and a minimum threshold voltage of −4.5 V. Computational investigations indicted proper charge separation of the energy levels for the phenanthro[9,10‐d]imidazole containing nitro group. Frontier molecular orbitals and the packing patterns obtained from computational studies suggest an efficient band gap for better device operation. The ordered morphologies of the molecules obtained from SEM analysis prove to be beneficial in the OFET performance. The photophysical, electrochemical and thermal properties of the molecules are studied in detail. The research work majorly emphasized on structural designing of the phenanthro[9,10‐d]imidazoles for potential applications in organic devices. [ABSTRACT FROM AUTHOR]

Cover Feature: Synthesis of Phenanthro[9,10-d]imidazoles and their Potential Applications in Solution Processable Bottom-Gated OFETs (Asian J. Org. EN Organic electronics Phenanthro[9,10-d]imidazole Semiconductors OFET solution processing. Organic electronics, Phenanthro[9,10-d]imidazole, Semiconductors, OFET, solution processing. [Extracted from the article]

Facile and economic strategy to create a controlled self-structured architecture of semiconducting molecules is very crucial in the accomplishment of carbon electronic devices. A series of new unsymmetrically functionalized butterfly type triarylamines with electron donating/withdrawing substituents were synthesized. Simple and efficient solution based method was used as a successful strategy for OFET with improved characteristics. Binary solvent system with chloroform and toluene (7:3) has improved inter/intra molecular communication in the active layer. The morphology of the films was analyzed by SEM reveals the uniform packing. In addition post thermal annealing has enhanced the crystallinity with minimal grain boundaries. HOMO values -5.1 to -5.4 eV obtained from cyclic voltammetry ensure that these molecules can efficiently transport holes. OFET devices were fabricated in bottom gate top contact (BGTC) architecture by spin coating. Molecules exhibited typical p -channel transistor behavior with mobility up to 1 cm2 V−1s−1 with 106 I on/off current ratio. Density functional theory (DFT) visualized the packing and interaction of molecules and supported the efficient mobility. Our investigation gives insight into the role of solvents to control the film architecture in solution processing OFET device construction. Image 1 • New functionalized triarylamines are designed, synthesized and scrutinised for OFET applications. • HOMO level (-5.2–-5.4 eV) ensures efficient hole injection and transport. • Band gap tuned with respect to the electron donating and withdrawing substituents. • OFETs with bottom gate top contact architecture is fabricated by spin coating from a binary solvent mixture. • Exhibited higher melting points ensures the device durability with higher mobility up to 1 cm2 V−1 s−1 with 106 I on/off current ratio. [ABSTRACT FROM AUTHOR]