EFfects of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) doping on the hole conductivity of Alq3 layer are measured.In the hole-only device of Alq3,the current densities increase in 1-3 orders of magnitude upon doping with F4TCNQ,suggesting that the doping can effectively enhance the hole-injection and holetransport ability of Alq3.An organic light-emitting device using an F4TCNQ doped Alq3 layer as the holeinjection and hole-transport layer,and pristine Alq3 as the electron-transport and emitting layer is fabricated and characterized.Bright emission is achieved in the simple OLED with p-doped Alqa as the hole-transport layer and the intrinsic Alq3 as the electron-transport and emitting layer.The emitting efficiency and brightness of the device are further improved by inserting a thin electron block layer to confine the carrier recombination zone in the middle of the organic layers.