ORGANIC ELECTROLUMINESCENT ELEMENT, LIGHTING DEVICE, DISPLAY DEVICE, LIGHT-EMITTING THIN FILM AND COMPOSITION FOR ORGANIC ELECTROLUMINESCENT ELEMENT, AND LIGHT-EMITTING METHOD

摘要

The present invention addresses the problem of providing: an organic electroluminescent element which exhibits an enhanced light emitting efficiency; a lighting device and a display device, each of which is provided with said organic electroluminescent device; a light-emitting thin film; a light-emitting composition; and a light-emitting method. An organic electroluminescent element (10,101) which is provided with one pair of electrodes (105,107) and one or multiple organic layers (106) disposed therebetween and which is characterized in that both a compound which emits a thermally activated delayed fluorescence and a heavy atom compound are each contained in any of the organic layers (106), said heavy atom compound having an external heavy-atom effect of accelerating the intersystem crossing from the triplet excited state of the compound which emits a thermally activated delayed fluorescence to the singlet excited state thereof and thus enhancing the fluorescence.