Fig. 2

a Optical absorption spectra of C₆₀ single layer (30 nm) and PTCDA:CuPc (30 nm) films deposited on C₆₀ film of different thicknesses. All films were deposited on quartz glasses. b XRD spectrum of PTCDA:CuPc films with and without C₆₀ film. And AFM images of c C₆₀/PTCDA:CuPc and d PTCDA:CuPc films