Crystallization and Organic Field-Effect Transistor Performance of a Hydrogen-Bonded Quaterthiophene.

Crystalline thin films of π-conjugated molecules are relevant as the active layers in organic electronic devices. Therefore, materials with enhanced control over the supramolecular arrangement, crystallinity, and thin-film morphology are desirable. Herein, it is reported that hydrogen-bonded substituents serve as additional structure-directing elements that positively affect crystallization, thin-film morphology, and device performance of p-type organic semiconductors.

Solubility and crystallizability: facile access to functionalized π-conjugated compounds with chlorendylimide protecting groups.

Functional π-conjugated molecules are relevant for the preparation of new organic electronic materials with improved performance. However, their synthesis is often rendered difficult by their inherently low solubility, and the permanent attachment of solubilizing groups may change the properties of the material. Here, we introduced the chlorendylimidyl moiety as a new temporary protecting group for the straightforward large-scale synthesis of protected quarter-, sexi-, octathiophene, and perylene bisimide diamine and dicarboxylic acid derivatives.

Organic thin-film transistors: the passivation of the dielectric-pentacene interface by dipolar self-assembled monolayers.

In organic thin-film transistors (OTFTs), the conducting channel is located near the interface between the organic semiconductor and the oxide dielectric; this interface is crucial for transistor performance. Self-assembled monolayers (SAMs) on the interface reduce the negative influences of the oxide dielectric surface by decreasing the coupling of the carriers at the gate and the role of the active surface defects on transfer. In this paper, we show that SAMs carrying a dipole moment determine the OTFT performance by controlling the charge transfer between the oxide dielectric and the semiconductor.

Robust self-assembled monolayers of Ru(II) and Os(II) polypyridines on gold surfaces: exploring new potentials.

Metal complexes [M(phtpy)(pztpy)](PF(6))(2) (phtpy = 4'-phenyl-2,2':6',2''-terpyridine, pztpy = 4'-(N-piperazinyl)-2,2':6',2''-terpyridine, M = Ru, Os) were prepared and examined spectroscopically and electrochemically. The piperazine attachment was found to significantly modify the photophysical and electrochemical properties compared to the parent bis-terpyridine complexes, causing a red-shift of the (1)MLCT (23 nm, 53.9 eV) and a substantial cathodic shift of the redox potential (0.

Sublimation not an innocent technique: a case of bis-cyclometalated iridium emitter for OLED.

Isomerization of a neutral bis-cyclometalated iridium(III) complex has been observed for the first time during the preparation of vacuum-processed organic light-emitting devices (OLEDs) and reproduced in solution. Isolation of the isomer revealed a cis organization of the two pyridine rings of the cyclometalating ligands. Photophysical studies show very similar emission properties of the two isomers.

Luminescence-detected phase transitions in lanthanide-containing liquid crystals.

Complexes between lanthanide nitrates and a pro-mesogenic 18-membered diaza-substituted coronand are luminescent both as powders and liquid crystals (between 87 and 195 degrees C), and the phase transitions are detected by monitoring luminescence intensity and lifetime.