Effect of annealing copper phthalocyanine on the performance of interdigitated bulk-heterojunction organic photovoltaic cellsN.N. Wang, J.S. Yu, Z.L. Yuan and Y.D. JiangEur. Phys. J. Appl. Phys., 58 2 (2012) 20201DOI: https://doi.org/10.1051/epjap/2012110404