Ambient Processable and Stable All-Polymer Organic Solar Cells

In this work, the way in which ambient moisture impacts the photovoltaic performance of conventional PCBM and emerging polymer acceptor-based organic solar cells is examined. The device performance of two representative p-type polymers, PBDB-T and PTzBI, blended with either PCBM or polymeric acceptor N2200, is systemically investigated. In both cases, all-polymer photovoltaic devices processed from high-humidity ambient conditions exhibit significantly enhanced moisture-tolerance compared to their polymer-PCBM counterparts. The impact of moisture on the blend film morphology and electronic properties of the electron acceptor (N2200 vs PCBM), which results in different recombination kinetics and electron transporting properties, are further compared. The impact of more comprehensive ambient conditions (moisture, oxygen, and thermal stress) on the long-term stability of the unencapsulated devices is also investigated. All-polymer solar cells show stable performance for long periods of storage time under ambient conditions. The authors believe that these findings demonstrate that all-polymer solar cells can achieve high device performance with ambient processing and show excellent long-term stability against oxygen and moisture, which situate them in an advantageous position for practical large-scale production of organic solar cells.