Graphene Oxide by UV-Ozone Treatment as an Efficient Hole Extraction Layer for Highly Efficient and Stable Polymer Solar Cells.

Abstract

The hole extraction layer has a significant impact on the achievement of high-efficiency polymer solar cells (PSCs). Here, we report an efficient approach to direct UV-ozone treatment by larger device performance enhancement employing graphene oxide (GO). The dramatic performance enhancement of PSCs with the P3HT:PCBM blend as an active layer was demonstrated by the UV-ozone treatment of GO for 30 min: best power conversion efficiency (PCE) of 4.18%, fill factor of 0.63, Jsc of 10.94 mA cm-2, and Voc of 0.61 V, which are significantly higher than those of the untreated GO (1.82%) and highly comparable PEDOT:PSS-based PSCs (3.73%). In addition, PSCs with UV-ozone-treated GO showed a longer stability than PSCs with PEDOT:PSS. The significant enhancement of PCEs of PSCs can be attributed to the fact that ozone molecules can oxidize GO into CO2 and leave highly conductive graphene particles. We suggest that this simple UV-ozone treatment can provide an efficient method for highly efficient GO hole extraction in high-performance PSCs.