Array substrate and preparation method thereof, display panel and display device

The invention discloses an array substrate and a preparation method thereof, a display panel and a display device. The array substrate (100) is provided with a display area (AA) and a transition area (DUM) arranged on at least one side of the display area (AA). The array substrate (100) comprises a first substrate (1), an insulating layer group (3), a first electrode layer (4) and a conductive enhancement layer (5), the insulating layer group (3) is arranged on one side of the first substrate (1), and a concave part (33) is arranged on the insulating layer group (3) and is positioned in the transition region (DUM); the first electrode layer (4) is arranged on one side, deviating from the first substrate (1), of the insulating layer group (3); the conductive enhancement layer (5) is arranged on the side, away from the first substrate (1), of the first electrode layer (4), and the orthographic projection of the conductive enhancement layer (5) on the first substrate (1) is located in the orthographic projection of the first electrode layer (4) on the first substrate (1). The light transmittance of each part of the display area (AA) of the array substrate (100) is basically consistent.