Organic planar heterojunction solar cell optimisation with ITO obtained by ion beam sputtering B. Ratier, W. Hojeij, B. Lucas and A. Moliton Eur. Phys. J. Appl. Phys., 36 3 (2006) 289-294 Published online: 15 November 2006 DOI: 10.1051/epjap:2006133