Takeshi Yasuda

A tetrathiafulvalene derivative (TTF-1) was introduced into perovskite solar cells as a dopant-free hole-transporting material, yielding an efficiency over 11%.

Abstract The contact angle of a water droplet on the surface of a solid polymer or hydrogel (water‐swollen three‐dimensional network) depends on whether a hydrophilic moiety of the polymer molecule is oriented towards the air interface or towards the bulk of the solid, but not on the hydrophilicity of the molecule. Therefore, the short‐range rotational mobility of a polymer molecule has a major influence on the apparent hydrophilicity of a polymer surface as measured by the contact angle of water. By the came principle, the abnormally large hysteresis effect observed in advancing and receding contact angles of water on some polymer surfaces can be attributed to the reorientation of hydrophilic moieties of polymer molecules at the surface. These factors are demonstrated by selected polymer surfaces with different degrees of mobility at the polymer‐air interface.

Field-effect transistors consisted of vacuum-sublimed polycrystalline pentacene films and calcium source-drain electrodes were prepared and device characteristics were evaluated in an oxygen-free condition. The field-effect transistor showed typical ambipolar characteristics and field-effect hole mobility of 4.5×10−4cm2/Vs and field-effect electron mobility of 2.7×10−5cm2∕Vs were estimated from saturation currents. Appearance of an electron enhancement mode in pentacene field-effect transistors was ascribed to the lowering of barrier for electron injection at source-drain electrodes. Effective elimination of electron traps using an oxygen-free condition was found to be another requirement for the observation of ambipolar behavior in pentacene.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTContact Angle of Water on Polymer SurfacesT. Yasuda, T. Okuno, and H. YasudaCite this: Langmuir 1994, 10, 7, 2435–2439Publication Date (Print):July 1, 1994Publication History Published online1 May 2002Published inissue 1 July 1994https://pubs.acs.org/doi/10.1021/la00019a068https://doi.org/10.1021/la00019a068research-articleACS PublicationsRequest reuse permissionsArticle Views7193Altmetric-Citations132LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts