The invention discloses a system for displaying images comprising an organic electroluminescent device. The organic electroluminescent device comprises a pixel area including a plurality of sub-pixels, a switching TFT having a first silicon layer with a first thickness and a driving TFT having a second silicon layer with a second thickness. Each sub-pixel includes a switching region with a switching TFT thereon and a driving region with a driving TFT thereon. Specifically, a difference between the first thickness and the second thickness at least exceeds 10%. Fabrication methods of the system are also provided.