A review of progress and challenges in the research developments on organic solar cells

Solar energy, being renewable and pollution-free, has opened the path for compensating for the exploitation of non-renewable energy sources via advancements in photovoltaic technology. Solar cells have made a lot of progress over time, which has made them smaller in size and more efficient. The development of novel acceptor and donor materials, interfacial materials for better charge-carrier collection, and optimization of phase-separation morphology contribute to remarkable enhancements in the power conversion efficiency (PCE) of organic solar cells (OSCs) has reached 19%. Several challenges remain in the way of achieving PCEs of more than 20%. However, maintaining the long-term stability and higher efficiency of OSCs compared to other types of solar cells is still a major impediment to their commercialization. The fundamental design, current advances in organic materials, operation of organic photovoltaic cells, critical features of their performance, and recent work in understanding the degradation processes of OSCs are reviewed and discussed in this paper. In addition, the challenges that remain to solve in the OSCs area are also discussed.