Table 4: The efficiency improvement of solar cells with various active layers under condition of 0.1 sun.

Substrate P3HT:PCBM P3HT:PCBM+N719 P3HT:PCBM+N719+GNP (%) (%) Improvement (%) (%) Improvement (%) Glass 4.1 4.36 6.34 4.76 16.1 PI 3.27 3.68 12.54 4.65 42.2 PET 2.24 2.38 6.25 3.21 43.3