Tokyo City University and AIST Achieve Record 25.14% Efficiency in Perovskite/CIGS Tandem Solar Cell

ペロブスカイトニュース Japan

Overview

Tokyo City University and the National Institute of Advanced Industrial Science and Technology (AIST) have achieved a world-record conversion efficiency of 25.14% for a perovskite/CIGS tandem solar cell. This breakthrough surpasses the theoretical limits of single-junction devices by leveraging the complementary bandgaps of perovskite and CIGS materials. The integration of perovskite’s tuneable bandgap and low-cost processing with CIGS’s high efficiency and stability marks a significant stride towards next-generation, high-efficiency solar cells applicable to diverse fields.

In Depth

Background

Further expansion of solar energy necessitates technologies that can surpass the theoretical conversion efficiency limits (Shockley-Queisser limit) of conventional single-junction solar cells. Tandem solar cells, which stack multiple solar cells with different bandgaps, are a promising approach to utilize the solar spectrum more effectively and achieve higher efficiencies. Perovskite solar cells are considered ideal top-cell materials for tandem structures due to their excellent light absorption properties and ease of bandgap tuning. Copper Indium Gallium Selenide (CIGS) solar cells, a thin-film technology, are known for their high efficiency and good stability, making their combination with perovskites highly anticipated.

Key Findings / Results

A joint research team from Tokyo City University and the National Institute of Advanced Industrial Science and Technology (AIST) has announced the development of a new perovskite/CIGS tandem solar cell, achieving a world-record power conversion efficiency of 25.14%. This unprecedented efficiency was realized through a design that maximizes the spectral response characteristics of both materials: the high-bandgap perovskite layer efficiently absorbs short-wavelength light, while the CIGS bottom cell captures the remaining long-wavelength photons. The research team implemented innovative interface engineering to minimize charge recombination losses at the perovskite/CIGS interface and precisely optimized the material composition and thickness of each layer. These efforts significantly improved current matching between the two sub-cells, leading to a substantial enhancement in the overall performance of the tandem structure.

Technical Significance & Outlook

The achievement of 25.14% efficiency in perovskite/CIGS tandem solar cells represents a critical milestone in the evolution of next-generation photovoltaic technology. This breakthrough demonstrates the potential to overcome the efficiency limitations of traditional silicon solar cells, enabling more power generation from a smaller installation area. Combining perovskite’s flexibility with CIGS’s durability opens up broad application possibilities, including building-integrated photovoltaics (BIPV), lightweight flexible devices, and even aerospace applications. The research team plans to scale up this high-efficiency technology for larger module areas and conduct long-term reliability evaluations to pave the way for commercialization. This accomplishment not only reinforces Japan’s position at the forefront of global solar cell research and development but also contributes significantly to the proliferation of renewable energy.