Multiexciton Generation in Semiconductor Nanocrystals: A Potential Avenue Toward Efficient Solar Cells

Multiexciton generation, which means multiple electron–hole pairs generation excited by the absorption of a single photon with energy larger than the effective band gap, has drawn a large amount of attention due to the possible significant promotion of solar cells with high efficiency and low cost. Several solid reports have demonstrated that multiexciton generation can be enhanced in nanocrystals due to quantum confinement effect and the quantum yields were determined by spectroscopic measurements. In this review, we summarize previous theoretical and experimental works on mechanism, efficiency, controversy and challenges. Some recent applications and observations of multiexciton generation in solar cells are introduced briefly. Views to the near term future, directions for fundamental research of both existing and new materials and development of photovoltaic devices are also provided. In addition, we put forward the idea of some other possible applications of multiexciton generation in optoelectronic devices such as ultraviolet photodetectors and photocatalysis due to the high internal quantum efficiency.