Scalable Fabrication of Flexible Large-area Inverted Organic Photovoltaic Cells

Abstract

Scalable large-area inverted organic hotovoltaic (OPV) cells were fabricated on a flexible polyethylene naphthalate (PEN) substrate. To account for the scalability and impact of the substrate (rigid versus flexible), OPVs of various sizes (0.04-1.6 cm²) were fabricated on flexible PEN and rigid glass substrates. A single OPV cell area of up to 1.6 cm² can be fabricated using a solution process at a low temperature of < 160 ℃. It should be noted that all processes except those of the electrodes were conducted based on a solution process under ambient air conditions, not inside a N₂ filled glove box. It was found from the numerical calculations and experimental measurements that a lower photoconversion efficiency (PCE) for higher areas mainly comes from a degradation in the fill factor (FF). Solar cell characteristic parameters were measured under an AM1.5G spectrum (intensity of 100 mW/cm²), and the PCE was 1.8% and 2.0% for the OPV on the PEN and glass substrates, respectively.