Description TREASORES: producing cheaper large area organic optoelectronic devices using roll-to-roll processes; developing new transparent, conductive, flexible electrodes and better barrier films.TREASORES (Transparent Electrodes for Large Area, Large Scale Production of Organic Optoelectronic Devices) is a project that seeks to develop technologies to facilitate roll-to-roll production of organic optoelectronic devices. Roll-to-roll production (of electrodes, barrier layers and complete devices) will allow faster and larger production runs to give cheaper devices (<190 €/m2). The use of low-temperature processes (< 180 °C) ensures compatibility with most organic optoelectronic materials and reduces process costs. TREASORES will test the new technologies and processes on a large (i.e. production) scale for light-emitting devices (OLED and OLEC) and organic photovoltaic (OPV) devices.The challenges for the project consist of making every element of the devices flexible, whilst retaining characteristics such as transparency (>90%, for efficiency), good electrical conductivity (<10 ω/square) in some directions but good resistance in other directions (for efficiency and reliability), and very low permeability (for long life). To maximise the chance of success within the project, TREASORES will begin by examining in parallel 4 different kinds of transparent electrode, three kinds of substrate/barrier layers and two different encapsulation approaches. After assessment, the most promising technologies will be scaled up to R2R encapsulation at substrate webspeeds of > 1 m/min and complete R2R device fabrication.