Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) is commonly used as a hole transfer layer in polymer light emitting diodes (PLEDs). However, Indium tin oxide transparent electrodes are corroded by poly(styrenesulfonate) and the erupted indium diffuses into the active layer, which in turn decreases the brightness, efficiency and lifetime of the device. In this study, therefore, antimony tin oxide (ATO) was introduced as a hole injection layer (HIL) in PLEDs. The work function and pH of ATO were -5.1 eV and similar to 7.5, respectively. When annealed at 200 degrees C, high conductivity (similar to 0.18 S/cm) was observed, which represents good HIL characteristics. Here, the maximum luminance (26,114 cd/m(2)) and maximum efficiency (1.55 cd/A) of the PLEDs were increased by 33% and 20% respectively. Their stability improved as well. (C) 2012 Elsevier B.V. All rights reserved.