Capping layer, OLED display panel comprising capping layer and electronic device

The invention relates to a capping layer arranged on a cathode of an OLED display panel. A material of the capping layer comprises N-contained compound with a structure shown in a formula (I). According to the capping layer, small organic molecules applicable to an evaporation mode are used as the capping layer, and the practical feasibility is achieved. The molecules of the material of the capping layer are symmetrical molecule structures which are beneficial for regular arrangement of the molecules; the film formation stability and optical performance can be improved; moreover, through adoption of triamine derivatives containing carbazoles-benzo conjugated structures, a general absorption area of the material is in an ultraviolet wave band, and an absorption coefficient for visible light is small. The refractive indexes of the material of the capping layer are gradually reduced in a wavelength range of 430-650nm, difference values between high wavebands and low wavebands are small, namely the refractive index change for R/G/B colors is low, the light emergent efficiency influence deviation for the R/G/B is reduced, and the practicability on the panel is achieved.