EPJPV Highlight - Research on the benefits of multi-junction solar cells in the Special Issue “WCPEC-8”

Full spectrum utilization by 3-junction solar cell compared to Si solar cell

The Editors-in-Chief of EPJ Photovoltaics, Pere Roca i Cabarrocas and Jean-Louis Lazzari, are pleased to highlight an important paper published recently in the Special Issue on ‘WCPEC-8: State of the Art and Developments in Photovoltaics’.

The article “Overview and loss analysis of III–V single-junction and multi-junction solar cells” is the result of the joint efforts of Masafumi Yamaguchi (Toyota Technological Institute), Frank Dimroth (Fraunhofer Institute for Solar Energy Systems ISE), Nicholas J. Ekins-Daukes (University of New South Wales), Nobuaki Kojima and Yoshio Ohshita (both from Toyota Technological Institute).

In order to realize a clean energy society by using renewable energies, high-performance solar cells are very attractive. The development of high-performance solar cells offers a promising pathway towards achieving a high power per unit area for many applications. Since the efficiency limit of single-junction solar cells under 1-sun operation is 30-32%, multi-junction (MJ) or tandem solar cells are required to solve such an efficiency limit.

In other words, an important strategy to raise the efficiency of solar cells is stacking solars with different bandgaps to absorb different colors of the solar spectrum as shown in the figure. 39.5% efficiency under 1-sun (non-concentration) illumination has been demonstrated with the 3-junction solar cell and the MJ solar cells have great potential of more than 50%.

This paper shows the guiding principle for MJ solar cells for further improvement of conversion efficiency and reduction in cost in order to achieve widespread terrestrial deployment such as in solar cell powered vehicles. In addition, the Si MJ tandem solar cells (such as III-V/Si, II-VI/Si, chalcopyrite/Si and perovskite/Si tandem solar cells) are expected to play an important role as high-efficiency and low-cost solar cells become more and more of a hot topic.

The open access Special Issue is edited by Alessandra Scognamiglio, Robert Kenny, Shuzi Hayase and Arno Smets and addresses new concepts related to High Efficiency Materials and Devices. WCPEC-8 (World Conference on Photovoltaic Energy Conversion), the World’s biggest platform for PV research and development, took place in September 2022 in Milan and had 5 main topics: Silicon Materials and Cells, Evolving and Emerging Technologies; Tandems, Photovoltaic Modules and BoS Components, PV Systems Engineering, Integrated/applied PV, and Energy transition – Integration, Storage, Sustainability, Policy, Finance, Ecology, Society.

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