Additives for morphology control in high-efficiency organic solar cells

Bulk heterojunction (BHJ) photovoltaics represent one of the most promising technologies in low-cost, high-throughput, environmentally friendly energy conversion. Morphological control is one pillar of the recent remarkable progress in power conversion efficiency. This review focuses on morphological control by processing with solvent additives, which has been extensively adopted and exhibits promising compatibility with large-scale processing. Recent investigations including material selection, morphological variations at various length scales, and interpretations of the interaction among additives and BHJ materials will be discussed. Insights into the role of solvent additives represent an important resource for further improvement in materials and processing designs.