Chinese Scientists Achieve 33% Efficiency in Solar Cells with Enhanced Durability

Researchers in China have introduced a targeted passivation technique that markedly enhances the efficiency of perovskite/silicon tandem solar cells, potentially overcoming a major obstacle to their commercial use.

These tandem solar cells combine a perovskite layer atop a conventional silicon cell, allowing them to capture a broader range of the solar spectrum and achieve efficiencies that surpass those of silicon cells alone.

Innovative Passivation Method for Solar Cells

The research team concentrated on reducing electrical leakage caused by uneven perovskite layer deposition on industrial silicon substrates.

In this tandem configuration, the perovskite top cell efficiently absorbs high-energy photons, while the silicon bottom cell is optimized to capture lower-energy light.

This layered setup theoretically exceeds the efficiency limits of single-junction silicon cells and could lead to lighter, more powerful solar cells, increasing accessibility and use.

Industrial silicon wafers often have pyramid-textured surfaces to minimize reflection and enhance light absorption. Although beneficial for traditional silicon cells, these textures hinder uniform perovskite coating, resulting in defect sites that cause localized leakage currents, which diminish overall efficiency and stability.

Scientists from the Ningbo Institute of Materials Technology and Engineering (NIMTE) under the Chinese Academy of Sciences, along with collaborators at Soochow University and Taizhou University in Jiangsu Province, developed a peak-selective passivation strategy to address this issue.

They utilized polystyrene nanospheres as a template to deposit a thin insulating aluminum oxide layer specifically on the peaks of the silicon pyramids. This method blocks leakage paths without disrupting the main surface area necessary for effective charge transport.

Testing and Results of the New Approach

The team evaluated their technique using a device with an active area of about one square centimeter, achieving a power conversion efficiency near 33 percent. The solar cell maintained approximately 90 percent of its initial efficiency after 1,000 hours of continuous operation, demonstrating robust operational stability.

“This strategy is simple and compatible with existing industrial production lines, bringing perovskite/silicon tandem solar cells a step closer to commercial applications,” stated Ye Jichun, a corresponding author of the study, as reported by state-owned media.

The global solar sector aims to surpass the typical 22-24 percent efficiency range of mass-produced silicon modules.

Tandem solar cell architectures are among the most promising solutions, although scaling them has been difficult due to interface and deposition challenges on textured substrates.

By limiting passivation to defect-prone areas, the new method avoids the performance compromises often associated with broader surface treatments. Its compatibility with current manufacturing processes could hasten adoption and reduce costs for high-efficiency solar installations in utility-scale, rooftop, and specialized markets.

Despite promising laboratory outcomes, additional research is required to confirm performance at larger scales and under diverse environmental conditions.