KIT and University of Valencia Pioneer Scalable Tandem Solar Cells with High-Throughput, Solvent-Free Vacuum Processing and Tunable Bandgaps

Photonics Spectra Germany, スペイン

Overview

Researchers at the Karlsruhe Institute of Technology (KIT) and the University of Valencia have engineered a high-throughput, solvent-free vacuum process for fabricating both single-junction and perovskite-silicon tandem solar cells. This novel technique ensures highly uniform perovskite layer deposition on textured silicon and offers precise bandgap control through mixed-halide organic source adjustments. The innovation marks a crucial step towards scalable manufacturing and optimized performance for next-generation, high-efficiency photovoltaics.

In Depth

Background

Perovskite-silicon tandem solar cells represent a leading candidate for next-generation photovoltaics, promising ultra-high efficiencies that can surpass the theoretical limits of conventional single-junction solar cells. However, their widespread commercialization has been significantly impeded by critical challenges in manufacturing scalability, cost-effectiveness, and device reproducibility, particularly concerning the mass production of complex tandem structures at an economically viable cost. Addressing these bottlenecks, a collaborative research team from the Karlsruhe Institute of Technology (KIT) and the University of Valencia has achieved a major breakthrough. They have developed an innovative high-throughput, solvent-free vacuum process applicable to both single-junction perovskite solar cells and two-terminal perovskite-silicon tandem configurations. This new technology is poised to dramatically accelerate manufacturing speed and enhance scalability, offering a compelling alternative to traditional solvent-based processes.

Key Findings

• High-Throughput, Solvent-Free Vacuum Deposition: The developed process marks a significant departure from conventional solution-based methods by eliminating the use of hazardous solvents. This not only reduces environmental impact and streamlines manufacturing costs but also leverages vacuum conditions to achieve superior layer uniformity and purity. The result is enhanced device performance reproducibility, a critical factor for industrial deployment.
• Uniform Perovskite Layers on Textured Silicon Subcells: A key innovation lies in the process’s ability to deposit exceptionally uniform perovskite layers directly onto textured silicon subcells. While textured silicon is crucial for maximizing light trapping in tandem devices, achieving homogeneous thin-film deposition on its inherently uneven surface has historically presented a formidable technical hurdle. This breakthrough overcomes that challenge, offering greater design flexibility and paving the way for even higher efficiency tandem architectures.
• Precise and Tunable Bandgap Control: The research demonstrates precise control over the perovskite absorber layer’s bandgap. By meticulously adjusting the ratio of mixed-halide organic sources, such as methylammonium iodide and methylammonium bromide, researchers can fine-tune the material’s light absorption properties. This capability is vital for designing tandem devices that efficiently absorb different portions of the solar spectrum, thereby maximizing overall power conversion efficiency.

Collectively, these advancements represent a major leap towards the commercialization of perovskite-silicon tandem solar cells. By simultaneously reducing manufacturing costs, significantly boosting production throughput, and enhancing both device performance reproducibility and reliability, this technology lays the groundwork for large-scale industrial deployment. This approach is anticipated to substantially improve the cost-performance ratio of solar power generation, playing a pivotal role in accelerating the global adoption of renewable energy.