| 초록 |
We demonstrate a highly efficient inverted bulk heterojunction (BHJ) solar cell using a wet-chemically prepared doped ZnO with a self-organized ripple nanostructure and a blend of PTB7 and PC71BM as an active layer. In order to enhance the electron extraction efficiency, the ZnO ripple surface was modified with various metal carbonate materials including Li2CO3, K2CO3, Na2CO3, Cs2CO3, and (NH4)2CO3. The inclusion of an additional metal carbonate layer led to gradient doping of the ZnO ripple layer and improved the electron extraction properties by modifying the energy level without destroying the ZnO ripple structures. The highest performing solar cells were fabricated with Li2CO3 and yielded a PCE of 10.08%; this value represents a ~14% increase in the efficiency compared to solar cells without a metal carbonate treatment. |
