Hisaaki Tanaka

Emerging evidence, although currently very sparse, suggests the presence of "lineage-specific dependency" in the survival mechanisms of certain cancers. TTF-1 has a decisive role as a master regulatory transcription factor in lung development and in the maintenance of the functions of terminal respiratory unit (TRU) cells. We show that a subset of lung adenocarcinoma cell lines expressing TTF-1, which presumably represent those derived from the TRU lineage, exhibit marked dependence on the persi

Fluoroalkylsilane (FTS) acts as an efficient p-type dopant for organic semiconductors. FTS-doped films of the semicrystalline PBTTT polymer exhibit relatively high conductivities. We demonstrate that highly doped PBTTT films exhibit a metallic nature with clear Pauli paramagnetism as observed microscopically using electron spin resonance spectroscopy. The metallic state is realized within crystalline grains, as confirmed from the anisotropy of the ESR signal.

Charge carrier concentration in operating field-effect transistor (FET) of regioregular poly(3-hexylthiophene) has been directly determined by electron spin resonance (ESR). ESR signals of field-induced polarons are observed around g=2.003 under the application of negative gate-source voltage (Vgs). Upon applying drain-source voltage (Vds), ESR intensity decreases linearly in the low Vds region, reaching to about 50% of the initial intensity at the pinch-off point (Vds≅Vgs). For larger absolute

Abstract Backbone rigidity of conjugated polymers is suggested to play an essential role in realizing high-mobility transistors through the efficient interconnection of crystalline domains by tie molecules as discussed for the recently-developed donor-acceptor (DA)-type copolymers. However, no studies have directly observed interdomain hopping in these DA copolymers. Here, highly-efficient interdomain charge transport is observed in two typical high-mobility DA copolymers from the microscopic ob

Charge carrier concentration in operating organic field-effect transistors (OFETs) reflects the electric potential within the channel, acting as a key quantity to clarify the operation mechanism of the device. Here, we demonstrate a direct determination of charge carrier concentration in the operating devices of pentacene and poly(3-hexylthiophene) (P3HT) by field-induced electron spin resonance (FI-ESR) spectroscopy. This method sensitively detects polarons induced by applying gate voltage, giv

ESR measurements have been performed on quasi-one-dimensional iodo-bridged diplatinum complexes (MMX-chains) Pt 2 (RCS 2 ) 4 I (R = n -butyl ( 1 ) and n -pentyl ( 2 )) in the temperature range between 4 K and room temperature. Both complexes show a steep drop in spin susceptibility at approximately 210 K, caused by the formation of a nonmagnetic alternate-charge-polarization (ACP) state at a low-temperature (LT) region for complex 1 , and also presumably so for complex 2 . Furthermore, thermal e

Electron spin resonance (ESR) measurements are performed on field-induced charge carriers in high-mobility organic transistors of polycrystalline dioctylbenzothieno[2,3-b]benzothiophene (C${}_{8}$-BTBT) films. The angular dependences of the ESR spectra are well fitted by orthorhombic $g$ values with the largest component of ${g}_{Y}$ $=$ 2.0110 nearly parallel to the normal direction of the substrate but tilted by 5\ifmmode^\circ\else\textdegree\fi{}. The results indicate a highly organized end-

Electronic state of charge carriers, in particular, in highly doped regions, in thin-film transistors of a semicrystalline conducting polymer poly(2,5-bis(3-alkylthiophene-2-yl)thieno[3,2-b]thiophene), has been studied by using field-induced electron spin resonance (ESR) spectroscopy. By adopting an ionic-liquid gate insulator, a gate-controlled reversible electrochemical hole-doping of the polymer backbone is achieved, as confirmed from the change of the optical absorption spectra. The edge-on

Abstract Triethylene glycol, a common side chain, is attached to two different dye moieties, diketopyrrolopyrrole (DPP) and isoindigo (II), and their bromo derivative monomers are copolymerized, respectively, with common bisstannyl alkylated bithiophene via Stille coupling. The resulting donor–acceptor low‐bandgap copolymers, namely, PTDPP‐DT and PTII‐DT, are rationally deigned and synthesized conjugated polymeric systems suitable for doping. Both polymers are successfully investigated as single

Light-induced ESR (LESR) measurements have been performed on the composites of regioregular poly(3-alkylthiophene) (RR-P3AT) and C60 by using polymers having different alkyl chains (CmH2m+1 with m=6, 8, 10, 12). The quadrimolecular recombination (QR) kinetics of photogenerated charge carriers, previously reported, have been confirmed for all the composites from the excitation power (Iex) dependence of the LESR intensity showing an ∼Iex0.25 dependence. The time decay of LESR intensity is also con

Light-induced electron spin resonance (LESR) measurements have been performed on the composites of regioregular polythiophene derivatives and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) in order to study the recombination kinetics of photogenerated charge carriers. We adopt two regioregular polymers with different side chains; head-to-tail poly(3-hexylthiophene) (RR-P3HT) and head-to-head poly(3-dodecynylthiophene-2,5-diyl) [HH-P3(C≡CDec)Th]. In both systems, two LESR signals due to positi

ESR measurements have been performed on a quasi-one-dimensional (Q1D) halogen-bridged binuclear metal-complex ${\mathrm{Pt}}_{2}{(n\text{\ensuremath{-}}\text{pentyl}\mathrm{C}{\mathrm{S}}_{2})}_{4}\mathrm{I}$ which exhibits successive electronic phase transitions. Anisotropy of the ESR linewidth shows a drastic change around $215\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ where the phase transition takes place between a nonmagnetic alternate-charge-polarization (ACP) state for low temperatures and a

Abstract Elucidating the interrelation between the molecular structure and charge transport properties in conjugated polymer thin films is an essential issue in developing the design principle of high‐performance polymer materials for application in organic electronics. In particular, the backbone planarity is suggested to be a key element that governs the transport performance, especially in recently developed donor–acceptor (D–A)‐type copolymers exhibiting high mobility, whereas the direct eva