Energy band diagrams of (A) ITO/ZnOnp/P3HT/Ag, (B) ITO/ZnOnp/TIPS-pentacene/Ag, (C) ITO/ZnOnp/PCBM/P3HT/Ag and (D) ITO/ZnOnp/PCBM/TIPS-pentacene/Ag devices as determined using IP measured by PESA (measured by UPS for ZnO), optical Eg determined from the U
