Masashi Mamada 교수

This review highlights organoboron-based multiple-resonance compounds’ synthetic strategies classified as one-pot borylation, one-shot borylation, and late-stage functionalisation, and explores material structure–photophysical property correlations.

Thermally activated delayed fluorescence (TADF) materials have shown great potential for highly efficient organic light-emitting diodes (OLEDs). While the current molecular design of TADF materials primarily focuses on combining donor and acceptor units, we present a novel system based on the use of excited-state intramolecular proton transfer (ESIPT) to achieve efficient TADF without relying on the well-established donor-acceptor scheme. In an appropriately designed acridone-based compound with

Two novel thiazolothiazole derivatives with trifluoromethylphenyl groups were synthesized and characterized by differential scanning calorimetry, X-ray single crystal analysis, UV−vis absorption spectroscopy, cyclic voltammetry, field-effect transistor (FET) characteristics, and X-ray diffraction. The FET characteristics of thiazole−thiazolothiazole derivatives are strongly dependent on the nitrogen positions. The derivative with a 2-(4-trifluoromethylphenyl)thiazole unit afforded a high perform

Polycyclic benzimidazole derivatives, an important class of compounds in organic electronics and photovoltaics, were prepared using a solvent-free "green" process based on heating carboxylic acid anhydrides and arylene diamines in the presence of zinc acetate in the solid state. Products were isolated and purified directly by train sublimation of the crude reaction mixtures. The reaction conditions were optimized using various carboxylic acid anhydrides. Optical and electrochemical properties of

Understanding excited-state dynamics is critical for improving the photoluminescence (PL) efficiency of exciplexes. A series of exciplexes based on conventional hole-transporting materials as donor and newly developed phenylpyridinato boron derivatives as acceptor were investigated. High PL efficiencies were achieved in only some combinations, and a large difference in performance among combinations provided insight into nonradiative processes in exciplex systems. Furthermore, the triplet local

There have been only a limited number of reports on solution-processed n-channel organic thin-film transistor (OTFT) devices with high levels of electrical performance because the material design process for n-type organic semiconductors is relatively difficult compared with p-type semiconductors, and further chemical modification of the functional groups is required. As a result, the development of soluble n-type organic semiconductors with high carrier mobilities has remained a challenge. Our

Abstract There is increasing interest in thermally activated delayed fluorescence (TADF) in materials, and to understand its mechanism in the excited state dynamics. Recent challenges include color purity, efficient deep‐blue emission, fast exciton decay lifetimes, high reverse intersystem crossing rates ( k RISC ), low‐efficiency roll‐off in organic light‐emitting diodes (OLEDs), and long device lifetimes. Here, a series of compounds having benzonitrile and carbazole rings are examined, that pr

Isomerically pure syn-/anti-anthradithiophene derivatives have been developed in the past few years. Although anti-isomers showed higher field-effect mobilities than mixture of isomers have been reported, a detailed comparison of syn-isomer and anti-isomer molecules has not been carried out. In this study, we took newly synthesized pure unsubstituted syn-/anti-anthradithiophenes (ADTs) and compared their single crystal structures, physical properties and semiconducting behavior with a previously

Abstract Advanced organic laser dyes exhibiting high solubility and bipolar behavior are developed based on a structure combining bis‐stilbene with carbazole (BSBCz). The materials show high photoluminescence quantum yields and large radiative rate constants in solutions, crystals, and blend and neat films. The introduction of alkyl groups significantly improves the solubility of BSBCz, and solution‐processed films of the alkyl‐substituted derivatives exhibit amplified spontaneous emission thres

A series of new benzimidazole derivatives were synthesized by the solid-state condensation and direct sublimation (SSC-DS) method and their physical properties were investigated. The reaction yields and product stability were significantly affected by the identity of the diamine and anhydride substituents. On the other hand, the substituents of the benzimidazole ring allowed fine tuning of the emission maxima, fluorescence quantum yields, and redox potentials. The HOMO-LUMO levels were estimated

Designing stable open-shell organic materials through the modifications of the π-topology of molecular organic semiconductors has recently attracted considerable attention. However, their uses as an active layer in organic field-effect transistors (OFETs) are very limited, and the obtained hole and electron charge mobilities are around 10^-3 cm² V^-1 s^-1. Herein, we disclose the synthesis of two peri-fused materials, so-called tetracenotetracene (TT) and

Diindeno[1,2-<i>b</i>:2',1'-<i>n</i>]perylene, a new derivative of the indenoacene family was synthesized, and its electronic, electrochemical, and electrical properties were investigated. This material has a closed shell electronic configuration which corresponds to a quinoidal structure with a low band gap of 1.35 eV. Molecular packing in the single crystal was studied by single-crystal X-ray structural analysis, and this information was subsequently used in the determination of the charge tra

Quinones are promising moieties for n-type organic semiconductors due to their high electron affinity. Benzo[1,2-b:4,5-b']dithiophene-4,8-dione derivative with a quinone moiety have been synthesized, characterized, and used as active layer of organic field-effect transistors (OFETs). This derivative has deep LUMO level, leading to efficient charge-carrier injection and air stability. In addition, it forms a columnar structure with efficient intermolecular pi-pi and horizontal direction interacti

New anthraquinone derivatives were prepared and used as active layers of organic field-effect transistors (OFETs); these devices showed good n-type characteristics and the quinones were found to be useful for organic semiconductors in OFETs.

Ultrapure deep-blue emitters are in high demand for organic light-emitting diodes (OLEDs). Although color coordinates serve as straightforward parameters for assessing color purity, precise control over the maximum wavelength and full-width at half-maximum is necessary to optimize OLED performance, including luminance efficiency and luminous efficacy. Multiple-resonance (MR) emitters are promising candidates for achieving ideal luminescence properties; consequently, a wide variety of MR framewor