Efficient charge transport across proper interfacial contacts is crucial in organic solar cells. In this paper, the surface of the P3HT:PCBM bulk heterojunction (BHJ) layer is treated with ethylene glycol monomethyl ether (EGME) prior to cathode buffer layer and top cathode deposition. Comparing to the nontreated P3HT:PCBM active layers, enhancement of short-circuit current (Jsc) to about 11 mA/cm2 is observed in the EGME-treated P3HT:PCBM BHJ layers. On the other hand, two cathode buffer layers, ZnO nanoparticles (ZnO NPs) and LiF, are utilized to block holes and diminish the electron-hole recombination near the cathode, which consequently promote the open-circuit voltage (Voc) to about 0.6 V. To integrate these two approaches, the EGME-treated P3HT:PCBM active layer and the ZnO NPs or LiF cathode buffer layer are applied concurrently. These two approaches work synergistically to enhance the Jsc to 16.3 mA/cm2 or higher. With the distinct Jsc performance, the efficiencies of P3HT:PCBM cells using EGME treatment in combination with the ZnO/Al and LiF/Al cathodes are successfully amplified to 4.68% and 4.32%, respectively. The mechanism behind the synergistic amplification on Jsc will be analyzed based on the superficial morphology of the P3HT:PCBM active layer.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films