We fabricated bottom-emitting AMOLED displays with a simplest 2T-1C pixel design and inverted OLED, in which a common high voltage applied on R, G and B pixels at different low voltages for emitting at different threshold voltage. Emitting efficiency of R and B were ideally adjusted for gray level control with the same gamma curve. Mg, Ca and LiF/Al layers were studied for electron injection from bottom ITO cathode. WO3, hole injection layer, covered by an Al anode was explored. Preliminary results for transparent display in the replacement of Al layer by ITO will be shown.