Light-emitting element and light-emitting device

Abstract

It is an object of the present invention to obtain an organometallic complex that is capable of converting an excited triplet state into luminescence, a light-emitting element that can be driven for a long time, is high in luminous efficiency, and has a favorable long lifetime, and a light-emitting device using the light-emitting element. The present invention provides a light-emitting element that has a pair of electrodes (an anode and a cathode) and a light-emitting layer between a pair of electrodes, where the light-emitting layer includes an organometallic complex represented by the following general formula (5) and one of a compound that has a larger energy gap than the organometallic complex and a compound that has a larger ionization potential and a smaller electron affinity than the organometallic complex, and provides a light-emitting device using the light-emitting device.

Description

technical field

[0001] The present invention relates to an organometallic complex capable of converting an excited triplet state into light, a light-emitting element using the organometallic complex, and a light-emitting device using the light-emitting element. Background technique

[0002] A light-emitting element using an organic compound is an element in which a layer containing an organic compound or a thin film of the organic compound emits light when an electric field is applied. Its light-emitting mechanism is said to be as follows: When a voltage is applied to electrodes sandwiching an organic compound thin film, an electron injected from the cathode and a hole injected from the anode recombine in the organic compound thin film to form a molecular exciton. When the molecular excitons return to the ground state, energy is released to emit light.

[0003] In such a light-emitting element, the organic compound layer is usually formed as a thin film of about 1 micron or...

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