Fully-sprayed flexible polymer solar cells with a cellulose-graphene electrode

Organic photovoltaic (OPV) technology provides energy where conventional photovoltaics are difficult to implement. The rise of efficiency due to the introduction of new polymers and the definition of strategies for the scale-up push OPV devices towards large-scale manufacturing. Here, spray coating has been employed as an easy and versatile scalable technique to deposit all the layers of flexible polymer solar cells starting from PET/ITO/Ag/ITO substrates. A foldable nanocomposite based on cellulose and sprayed graphene nanoplatelets has been applied as top electrode through lamination. The overall fabrication process has been conducted in air by using commercial materials. A significant power conversion efficiency higher than 3% has been achieved and the high quality of the lamination process has been demonstrated by bending and adhesion tests. Such photovoltaic devices are the first fully-sprayed prototypes on plastic substrate and the novel structure has also been effective for devices with active area up to 0.75 cm 2 .