Abstract: The present disclosure discloses an organic electroluminescent device and a preparation method thereof. The device includes a light-emitting layer, the light-emitting layer includes a host material, an auxiliary host material and a fluorescent dye; the host material is an exciplex prepared by mixing an electron donor material and an electron acceptor material, the auxiliary host material is a thermally activated delayed fluorescence material, a singlet energy level and a triplet energy level of the exciplex are higher than the single energy level and triplet energy level of the auxiliary host material. The above organic electroluminescent device can promote the reverse intersystem crossing of the host material and the auxiliary host material from the triplet excitons to the singlet excitons, enhance the Foster energy transfer, reduce the triplet exciton quenching, therefore the efficiency roll-off of the device is small and the external quantum efficiency is high.

Abstract: An electrical device (400) includes a substrate (300) having solder pads (215, 220) formed thereon and a self aligning electrical component (200) mounted to the solder pads (215, 220). The self aligning electrical component (200) includes a body having a cylindrical shape, a first terminal (205) formed on an inner region of the body, and a second terminal (210) formed around outer regions of the body surrounding the first terminal (205).