Control of measurement environments for high-efficiency organic photovoltaic cells

To fabricate a high-performance of organic photovoltaic (PV) cells, not only short-circuit photocurrent density (I-sc), but also fill factor (FF) should be improved. Here, we improved FF by controlling the measurement environment. Because of the prevention of electron trapping by oxygen in the organic semiconducting layer, FF in vacuum environment increased 40% compared with that in air Under 80 mW/cm(2) irradiation of air mass 1.5 global solar conditions at room temperature. Finally, we obtained a power conversion efficiency of 3.6% by controlling the measurement environment and the optimization of the organic PV cell Structure, where FF was markedly improved up to 0.61.