A series of metal-free porphyrin molecules with functionalized triarylamines at the meso-position are designed and synthesized. All the functionalized porphyrins possess good thermal stability and high decomposition temperatures over 422 °C and also exhibited electrochemical reproducibility. The calculated ionization potentials are in the range of −5.01 to -5.42 eV, and electron affinity levels are in between −2.47 and −2.91 eV, which supports stable charge ejection. Organic fieldeffect transistor (OFET) devices with bottom-gate/top-contact architecture are fabricated by a solution-processable technique. OFETs with an active layer of porphyrin with electron-accepting trifluorophenyl groups gave the highest charge carrier mobility of 4.4 cm 2 /Vs and an on/off ratio of 10 7 . The obtained results indicate these compounds to be efficient hole-transporting materials. This research work presents the highest mobilities of the porphyrins reported until now.

Phenanthro[9,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 10 9 and a minimum threshold voltage of À 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.

This work focuses on the development of high performance and air stable OFETs of functionalized phenanthro[9,10‐d]imidazoles. Among different strategies, structural tailoring of the molecules offers crucial responsibility in regulating the device operations. Solution‐processable bottom gate top contact OFETs are fabricated and characterized in ambient conditions. All the functionalized phenanthro[9,10‐d]imidazoles exhibit noticeable p‐type characteristics with high charge carrier mobility, high ON/OFF ratio and low threshold voltages. The compounds may find applications in the development of organic memory and other devices. More information can be found in the Full Paper by Samuthira Nagarajan et al.

A series of new zinc porphyrins were synthesized, and their charge transport property was tuned by introducing various groups. Triarylamine was introduced to the porphyrin moiety at the meso‐position as an electron donor, enhancing the charge carrier mobility. All the synthesized zinc porphyrins are thermally stable with a decomposition temperature over 178 °C. High frontier molecular orbitals levels of these compounds make them stable donor materials. SEM analysis of zinc porphyrins fabricated by spin‐coating resulted in diversely self‐assembled films. Field‐effect transistors were fabricated using bottom‐gate/top‐contact architecture (BGTC) by solution‐processable technique. The higher charge carrier mobility of 5.17 cm2/Vs with on/off of 106 was obtained for trifluoromethyl substituted compound due to better molecular packing. In addition, GIXRD analysis revealed zinc porphyrins films crystalline nature, which supports its better charge carrier mobility. The present investigation has validated that zinc porphyrin building blocks are an attractive candidate for p‐channel OFET devices.