Organic optoelectronic devices-flexibility versus performance

¹ XLIM UMR 6172-Université de Limoges/CNRS, 123 av. Albert Thomas, 87060 Limoges Cedex, France
² LPSMS, FST Errachidia, BP 509, Boutalamine, Errachidia, Morocco

Corresponding author: bruno.lucas@unilim.fr

Received: 28 July 2009
Revised: 5 January 2010
Accepted: 10 June 2010
Published online: 2 September 2010

Abstract

In this paper, we discuss the effect of flexible substrates on the characteristics of two organic optoelectronic devices, namely P3HT:PCBM-based photovoltaic bulk heterojunctions and pentacene-based phototransistors. In addition, we have developed anode materials deposited by ion beam sputtering, a technique which satisfies the low temperature deposition requirements associated with the use of plastic substrates. The anode materials consisted of indium tin oxide (ITO) and ITO/metal/ITO tri-layers. The use of tri-layer anodes in P3HT:PCBM-based solar cells resulted in an increase in the fill factor and the power conversion efficiency reached a value of 2% with an ITO(70 nm)/Ag(14 nm)/ITO(70 nm) anode deposited on a polyphthalate carbonate substrate. In the case of phototransistors, a photosensitivity of 1.6 × 10⁴ under illumination at 365 nm (with a power intensity of 7 mW/cm²) was obtained in the off-state of the transistor. We have fine-tuned the anode structure and deposition/annealing conditions towards flexible organic devices and optimal device characteristics.