Carrier multiplication could break the efficiency barrier in solar cell technology

Silicon solar cells, the most widely used solar cells, have a maximum efficiency limit of about 33 percent since they cannot fully convert solar power into electricity. However, emerging research in the past two decades has revealed a possible workaround – carrier multiplication, a process where one photon can create multiple electron-hole pairs. This method utilizes the high energy photons that would otherwise be wasted as heat to create multiple electron-hole pairs.

Maiti et al. present a comprehensive review of carrier multiplication in photovoltaics, covering how it can benefit solar cell research and what remains to be further investigated. The authors hope the review will help to further spark interest in the field, which could ultimately help improve solar cell technology.

“Interest in renewable energy, including solar energy, is rising due to environmental concerns about conventional energy sources,” said author Sourav Maiti. “The recent results of efficient carrier multiplication in bulk and bulk-like materials, nanocrystal assemblies and other materials are really promising.”

The review provides readers with an overview of both experimental and theoretical accomplishments, providing a baseline entry into the field. An evaluation of where the field stands offers ideas on future directions that could help move both fundamental science and technology forward.

Stemming from recent findings that quantum confinement is not strictly required for efficient carrier multiplication, there is substantial room for future work to focus on two-dimensional and bulk-like materials along with nanocrystal assemblies. Additionally, further theory, experimentation and device fabrication can help boost exploitation of efficient carrier multiplication.

Source: “Emergence of new materials for exploiting highly efficient carrier multiplication in photovoltaics,” by Sourav Maiti, Marco van der Laan, Deepika Poonia, Peter Schall, Sachin Kinge, and Laurens D.A. Siebbeles, Chemical Physics Reviews (2020). The article can be accessed at https://doi.org/10.1063/5.0025748 .