Organic electroluminescent (hereinafter referred to as EL) elements are thin and capable of achieving various emitting colors. Thus, applications of organic EL elements to light-emitting devices such as displays and lighting units are expected. However, organic EL elements have various problems.
For solving such problems, light-emitting elements utilizing electrochemiluminescence (hereinafter referred to as ECL) have been developed.
As described in JP-A 2008-84644 (KOKAI), the emitting layer of an ECL element is liquid. Thus, unlike an organic EL element, the emitting material of the ECL element can circulate in the emitting layer. Therefore, ECL elements are less prone to cause image burn-in as compared with organic EL elements.
Further, an organic EL element generally employs a multilayer structure including an emitting layer, charge-transporting layers, charge injection layers, and a pair of electrodes in order to achieve high luminous efficiency. By contrast, an ECL element can be composed only of an emitting layer in liquid form and a pair of electrodes. Thus, ECL elements can be manufactured at a lower cost as compared with organic EL elements.
In addition, unlike organic EL elements, ECL elements utilize an electrochemical reaction. Therefore, ECL elements can be driven at a lower voltage as compared with organic EL elements.
As above, ECL elements are superior to organic EL elements in various respects. However, light-emitting devices utilizing ECL elements have not yet been put to practical use.