In this paper, transparent conducting indium-zinc oxide ͑IZO͒ films have been grown on a hard polycarbonate ͑HPC͒ substrate without postdeposition annealing treatment. The electrical, optical, and structural properties of these prepared films are investigated by different dc sputtering powers, such as 50, 80, and 100 W/cm 2 , with/without the ion-assisted deposition ͑IAD͒ technique. An optimal IZO deposition condition is developed for flexible organic light-emitting device ͑OLED͒ applications. The IZO films grown at low temperature ͑ϳ50°C͒ with dc magnetron sputtering ͑100 W power͒ and the IAD technique were used to study the electroluminescence ͑EL͒ performance of the OLEDs. The EL results are better than those that are measured with commercial indium-tin oxide anodes and well above the electro-optical application standard.In recent years, transparent conducting oxide ͑TCO͒ thin films have been widely used as transparent electrodes for organic lightemitting diodes ͑OLEDs͒ because of their potential applications on color flat-panel displays. These displays are typically highly efficient and lightweight. They also have low-drive voltage and large-area flexibility. Ever since the first report of tris͑8-hydroxyquinoline͒ aluminum (Alq 3 ) emitting OLEDs, 1 many efforts have been devoted to the OLED design for enhancing performance. For example, various device configurations, fluorescent materials, and electrode technologies have been studied to improve the efficiency and stability of the OLEDs on indium-tin oxide ͑ITO͒ films. 2-5 Unfortunately, the invasion disadvantage of H 2 O, O 2 , etc., to react with Alq 3 and thus affect the lifetime still exists and is considered to be a critical issue. 6 The improvement in ITO film morphology, 7 such as preheated or post high-temperature annealed treatment, has been investigated for good adhesion to the OLED/ITO interface. However, this limits flexible application on hard polycarbonate ͑HPC͒ substrates.Therefore, there has been a growing interest in the development of new TCO films. These films have electrical and optical properties similar to those of the well-known ITO. Yet, a lower cost can be achieved for a wide range of applications. The indium-zinc oxide (IZO, Zn 2 In 2 O 5 ) film with high electrical conductivity and optical transparency is a potential candidate for ITO film substitution, because it uses a dc sputtering process on unheated substrates without a postdeposition annealing treatment. Moreover, because of their good chemical and thermal stability, 8 IZO films have also been widely utilized as the anode contact for hole injection into organic materials.Several methods have been suggested and used to prepare IZO films. These methods include sputtering, spray pyrolysis, metallorganic chemical vapor deposition, and laser deposition. 9 Among these methods, the dc magnetron sputtering is the most used industrial process due to its high rate, high volume, and large-area uniformity. 10,11 In this paper, we first employed different dc sputtering powers per area ͑i.e...