Spontaneously spreading film process to improve the photovoltaic performance of organic solar cells with PHJ structure.

Efficient charge transport and extraction within the active layer plays a major role in the photovoltaic performance of organic solar cells (OSCs). In this work, the spontaneously spreading (SS) process was utilized to achieve sequential deposition of the active layer with a planar heterojunction (PHJ) structure. The SS process avoids the damage of the upper layer solution to the lower layer film by the spin coating process.