Organic electroluminescence element, and light emitting apparatus, image forming apparatus, light emitting element array, display apparatus, and imaging apparatus each using the element

摘要

Provided are organic electroluminescence elements that suppress SP loss even in a strong cavity satisfying a λ/4 interference condition, thereby being improved in luminous efficiency. The organic electroluminescence elements emit light having a peak wavelength of 440 nm or more to 470 nm or less, in which a wavenumber difference δk (Re) between surface plasmons generated at respective reflecting electrode and transparent electrode falls within a specific range.

主权项

1. An organic electroluminescence element, comprising a first electrode formed of a metal layer, a first charge transport layer, an emission layer, a second charge transport layer, a second electrode formed of a metal layer, and an out-coupling layer in the stated order, the element causing light emitted by the emission layer to exit from a side of the second electrode, and the element emitting light having a maximum peak wavelength in an emission spectrum of 440 nm or more to 470 nm or less, wherein:
the first charge transport layer is in contact with the first electrode; the second charge transport layer and the out-coupling layer are each in contact with the second electrode; an optical path length L between a first interface between the first electrode and the first charge transport layer, and a second interface between the second electrode and the second charge transport layer satisfies the following relationship:
(−1−φ/π)×(λ/4) when a real part of a wavenumber of a surface plasmon generated at the first interface is represented by kr [rad/m] and a real part of a wavenumber of a surface plasmon generated at the second interface is represented by ks [rad/m], the following relationship is satisfied:
−4.5×106≦kr−ks≦2.1×106.