On August 11, the perovskite R&D team from the PV Technology Center of Tongwei Co., Ltd. published groundbreaking research in the prestigious energy journal ACS Energy Letters. The study, titled "Crystallization Modulation of Wide-Bandgap Perovskites on Textured Silicon for Tandem Solar Cells", systematically elucidates crystallization control mechanisms of wide-bandgap perovskites on textured silicon substrates, offering innovative solutions to enhance tandem solar cell performance. The team refined the vapor-solution two-step perovskite crystallization film formation theory, proposing a simple yet effective strategy for homogeneous film formation on fully textured tandem cells. Tongwei is the primary affiliation, with Dr. Wu Lin (Senior Engineer of Cell Development) as first author, and Dr. Hu Yuchao (Director Engineer of the department) and Dr. Zhang Yifeng as corresponding authors. This collaborative research was conducted with Prof. Bai Sai's team at University of Electronic Science and Technology of China.

The paper on the journal

While photovoltaics lead global green energy transition, rising power plant costs drive demand for higher-efficiency technologies. Perovskite/silicon tandem solar cells have emerged as a focal point due to their breakthrough efficiency potential. The core challenge lies in achieving high-quality perovskite film formation on textured silicon subcells. To maintain compatibility with fully textured commercial silicon cells, Tongwei employs the vapor-solution two-step film formation technique. However, this approach faces the dilemma of simultaneously balancing adequate reaction, compositional uniformity, conformal coverage on textured surfaces, and high crystallinity in wide-bandgap perovskite films, which restricts the improvement of tandem cell efficiency.

The perovskite R&D team from the PV Technology Center of Tongwei Co., Ltd. conducted in-depth research on the perovskite phase transition process, revealing the crystallization kinetics mechanism of wide-bandgap perovskites, clarifying the influence mechanisms of external conditions such as humidity and heat on film crystallization and degradation, and innovatively proposing a sequential crystallization modulation strategy. This scheme, through mass-producible processes and equipment, prepares perovskite films with uniform composition and reduced defects on fully textured commercial silicon substrates, ultimately achieving a photoelectric conversion efficiency of 31.58% (certified 31.4%), setting a new record for tandem cells based on commercial silicon cells.

The results of this project not only improve the mechanism of perovskite film formation but also provide a simple and feasible process optimization direction for the industrial production of high-performance perovskite/silicon tandem solar cells, promoting the industrialization progress of tandem cell technology and demonstrating Tongwei's leading technical strength in the tandem field.

Tongwei Global Innovation R&D Center

The Tongwei Global Innovation R&D Center is currently engaged in research and development across major photovoltaic technologies, including TOPCon, HJT, BC, and perovskite/silicon tandem cells. It covers all mainstream future technologies for solar cells and modules, driving the company's long-term growth through continuous exploration of advanced technological frontiers.

The Tongwei perovskite/silicon tandem cell laboratory, established in Q3 2022, aims to industrialize tandem cells by adopting a technology roadmap compatible with existing heterojunction production lines. The focus is on overcoming key mass production technical bottlenecks in tandem cell design, textured surface conformal film formation, interface passivation, low-temperature metallization, and module encapsulation. The laboratory has achieved a research efficiency of 34.69%, with 210 half-cell full-size cells reaching an efficiency of 27.52%. The first standard-format tandem module has been produced, and a megawatt-scale tandem pilot line is planned for completion in Q3 2025.

In the future, Tongwei will leverage its complete R&D system, continue to capitalize on its technological innovation advantages, and integrate 210 half-cell platforms, wafer thinning, silver-free metallization, and 0BB technologies to accelerate the mass production of perovskite-silicon tandem cells. This will establish a new "30%+ efficiency" pathway for the photovoltaic industry, supporting the global energy structure's transformation and upgrade.

【Title】:

Crystallization Modulation of Wide-Bandgap Perovskites on Textured Silicon for Tandem Solar Cells

【Authors】:

Wu Lin, Zhang Jiawei, Guo Ying, Yang Bo (UESTC), Hao Lei, Li Jiawen, Zhang Zhenming, Ma Chenglin, Wang Lan, Xu Yanchao, Liu Quan, Chen Yu, Yin Chunyang (UESTC), Liu Songlin, Zhang Dexiang, Ran Wenjin, Kang Zhangli (NIMTT), Zhang Yifeng, Bai Sai (UESTC), Hu Yuchao, Long Wei, Xing Guoqiang

【DOI】:

https://doi.org/10.1021/acsenergylett.5c01244