The invention discloses an OLED, a display panel and a display device to improve the light-emitting efficiency and THE service life of the OLED. The OLED includes an anode, a cathode, at least two light-emitting layers disposed between the anode and the cathode, a charge generating layer disposed between any two adjacent light-emitting layers, a first functional layer and a second functional layer. The charge generating layer includes a first hole transport substrate, a first electron transport substrate, a first P-type semiconductor dopant, and a first N-type semiconductor dopant. The first functional layer includes a second electron transport substrate and a second N-type semiconductor dopant. The second electron transport substrate and the first electron transport substrate have the same lowest unoccupied orbital energy level. The second functional layer includes a second hole transport substrate and a second P-type semiconductor dopant. The second hole transport substrate and the first hole transport substrate have the same highest occupied molecular orbital energy level.