▎ 摘　　要

NOVELTY - A light emitting device comprises an anode (2), a cathode (7) and a light emitting layer (5) arranged between the anode and the cathode. The material of the cathode comprises a cathode nanomaterial and poly-dopamine. The material of the cathode comprises cathode nanomaterial and dopamine. USE - Light emitting device. ADVANTAGE - The surface defect is inhibited. The interface bonding capability and carrier transmission capability are improved, so as to improve the luminous performance and service life of the device. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for a method for preparing light-emitting device, which involves: (A) providing a substrate; and (B) preparing a cathode on the substrate. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the light emitting device. Substrate (1) Anode (2) Injection layer (3) Light emitting layer (5) Cathode (7)