Kabushiki Kaisha Hayashibara Seibutsu Kagaku Kenkyujo

Kabushiki Kaisha Toyota Jidoshokki

Natsuko Ishida

Yasunori Taga

Hisayoshi Fujikawa

Sadaharu Suga

Makoto Satsuki

Makoto Fujiwara

Masahiko Ishii

Yoshifumi Kato

Koji Noda

Hisato Takeuchi

Takanori Murasaki

Kazushige Kojima

Satoshi Nakagawa

Kojiro Tachi

A method for producing a coumarin compound represented by Formula 1, which comprises a step of reacting a coumarin compound represented by Formula 1 with a compound having an aldehyde group and an activated methylene group; luminous agents for organic EL elements and organic EL elements which all comprise the coumarin compound; and displaying panels and information displaying apparatuses using the organic EL elements:&#xf8;(Z)m&#x2003;&#x2003;Formula 1wherein in Formula 1, &#xf8; is an aromatic ring, heterocycle, or a combination thereof, each Z is the same or a different coumarin group represented by Formula 2; and m is an integer of two or more; 

Coumarin compound

This invention has an objective to improve durability at elevated temperature in organic electroluminescent devices using coumarin derivatives as dopant in a luminescent layer. This invention attains the above objective by providing in the organic electroluminescent devices formed by laminating an anode, a hole injection layer, a hole transportation layer, a luminescent layer, an electron transportation layer and a cathode in this order, the luminescent layer which comprises as dopant the green light-emitting coumarin derivative and hole- and electron-transporting substances as host; said coumarin derivative consisting of a plurality of coumarin groups bound to an aromatic ring, heterocycle, or any combination thereof, and exhibiting a glass transition point of 150&#xb0; C. or higher or a melting point of 297&#xb0; C. or higher.

Organic electroluminescent device

An organic electroluminescent (EL) device which uses, as a luminescence-assisting agent, a novel coumarin derivative with a specific structure. The coumarin derivative effectively accelerates in such an organic EL device the transfer of excited energy in a host compound to a guest compound. Thus, the coumarin derivative affords the organic EL device which is superior in a color purity, luminescent efficiency and life expectancy when used in combination with appropriate host and guest compounds.

Organic electroluminescent element

An organic electroluminescent (EL) device which contains a novel coumarin derivative composed of a coumarin ring, a naphthalene ring with one or more hydrocarbon groups, and a five-membered hetero ring condensed with the naphthalene ring so as to give an electronic resonance through the coumarin and naphthalene rings. The coumarin derivative emits a visible luminescence with a satisfactory color purity, which consistently continues over a long period of time even at an elevated temperature when used in such an organic device.

Organic electroluminescence device

Growing community of inventors

Okayama, Japan

Natsuko Ishida