A display panel and a method for forming a display panel and a display device are provided. The display panel includes a plurality of pixels, a pixel of the plurality of pixels including a light-transmitting area; a substrate structure, including a first substrate; a first sub-gate insulation layer, located on a side of the first substrate close to a light-emitting surface of the display panel; a second sub-gate insulation layer, located on a side of the first sub-gate insulation layer close to the light-emitting surface of the display panel; and a first structure layer, located between the first sub-gate insulation layer and the second sub-gate insulation layer, where a refractive index of the first structure layer is between a refractive index of the first sub-gate insulation layer and a refractive index of the second sub-gate insulation layer.