Electroluminescent display device

An electroluminescent display device 310, comprising: a substrate 111 which may include an active area AA and a non-active area NA, the active area AA having an emission area EA; a planarization layer 115e,115f disposed on the substrate 111; a light emitting element 130 disposed on the planarization layer 115e,115f; a buffer layer 340 disposed on the planarization layer 115e,115f in an area excluding the emission area EA and having a plurality of holes 345 in a surface thereof; and a hydrogen trap layer 350 disposed on the buffer layer 340 and in the emission area EA. Also disclosed is a similar display device [410, fig. 14] wherein the hydrogen trap layer [450, fig. 14] is disposed only on the buffer layer [440, fig. 14]. The electroluminescent display device may comprise an oxide thin film transistor 120. The hydrogen trap 340 layer may comprise aluminium and may have a series of grooves formed in the surface thereof corresponding to the holes 345.