ORGANIC ELECTROLUMINESCENT ELEMENT, ORGANIC ELECTROLUMINESCENT DEVICE, ORGANIC EL DISPLAY DEVICE, AND ORGANIC EL LIGHTING
申请人:Mitsubishi Chemical Corporation
公开号:EP2592671A1
公开(公告)日:2013-05-15
The present invention is to provide a highly efficient organic electroluminescence element which has a long life and an organic electroluminescence device which includes the element. The invention relates to an organic electroluminescence element which comprises an anode, a luminescent layer, two or more electron transport layers and a cathode, in this order, wherein at least one of the two or more electron transport layers adjoins the luminescent layer, the luminescent layer contains a luminescent material and a charge transport material, the electron transport layer which adjoins the luminescent layer contains a charge transport material, the charge transport material contained in the luminescent layer and the charge transport material contained in the electron transport layer which adjoins the luminescent layer may be the same material or may be different material, when an electron affinity of the charge transport material which serves to transport electrons, among the charge transport materials contained in the luminescent layer, is expressed by EA1, and an electron affinity of the charge transport material which is the highest in an absolute value of electron affinity, among the charge transport materials contained in the electron transport layer that adjoins the luminescent layer, is expressed by EA2, then EA1 and EA2 satisfy the relationship represented by the following expression (1), and when an electron affinity of the charge transport material which is the highest in an absolute value of electron affinity, among the charge transport materials contained in the electron transport layer located on the most cathode side among the two or more electron transport layers, is expressed by EA3, and a work function of the cathode is expressed by WF, then EA3 and WF satisfy the relationship represented by the following expression (2):
本发明旨在提供一种使用寿命长的高效有机电致发光元件和一种包括该元件的有机电致发光器件。本发明涉及一种有机电致发光元件,它依次包括阳极、发光层、两个或多个电子传输层和阴极,其中两个或多个电子传输层中至少有一个与发光层相邻,发光层包含发光材料和电荷传输材料,与发光层相邻的电子传输层包含电荷传输材料、发光层中包含的电荷传输材料和与发光层相邻的电子传输层中包含的电荷传输材料可以是相同的材料,也可以是不同的材料、用 EA1 表示,而在与发光层相邻的电子传输层中所包含的电荷传输材料中,电子亲和力绝对值最高的电荷传输材料的电子亲和力用 EA2 表示,则 EA1 和 EA2 满足以下表达式 (1) 所表示的关系、当位于两个或多个电子传输层中最阴极一侧的电子传输层所含电荷传输材料中电子亲和力绝对值最高的电荷传输材料的电子亲和力用 EA3 表示,阴极的功函数用 WF 表示时,则 EA3 和 WF 满足以下表达式 (2) 所表示的关系: