Embodiments of the present disclosure relate to the field of display technology, and in particular, to an array substrate, a display panel and a display device thereof. The array substrate includes a substrate and a plurality of sub-pixels on the substrate. Each sub-pixel includes a pixel circuit. The pixel circuit includes a plurality of transistors. The plurality of transistors includes at least one oxide transistor. The array substrate further includes: an oxide semiconductor layer on the substrate, the oxide semiconductor layer comprising a channel region of the oxide transistor; a first planarization layer on the substrate and covering at least a portion of the oxide semiconductor layer; a barrier part on the side of the first planarization layer away from the substrate.