According to CCTV News, the research team of the Qingdao Institute of Bioenergy and Processes, Chinese Academy of Sciences has made a major breakthrough in the research of copper-zinc-tin-sulfur-selenium solar cells (CZTSSe). Its photoelectric conversion efficiency exceeded 15% and was certified by international authoritative organizations.CZTSSe is a next-generation solar cell technology with great potential, with significant core advantages:
-The main constituent elements are abundant in the earth's crust, do not rely on rare metals, and have low material costs;
-Prepared by solution method and thin film battery form, the preparation cost and material consumption are both low;
- Contains no toxic elements, is safe and environmentally friendly, has stable performance in complex environments, and is suitable for large-scale promotion and application.
Previously, the development of this technology was restricted by core problems—during the high-temperature preparation process, metal ions within the material tend to migrate disorderly, resulting in disordered crystal structure and increased defects, making it difficult to improve battery efficiency.
The research team proposed an innovative solution by introducing Li₂SnS₃'s special "interface phase" structure inside the material. This structure is like a "traffic conductor" that can guide metal ions to move along the correct route, balance the differences in ion migration, make the crystal structure more uniform and stable, significantly reduce internal defects of the material, and promote larger and neater grain growth, fundamentally improving the battery's power generation capacity.
With the help of this new mechanism, the research team achieved breakthroughs in a number of key indicators:
-The laboratory photoelectric conversion efficiency reaches 15.45%, and the internationally certified efficiency is 15.04%;
-Under the narrow band gap condition of 1.10eV, the open circuit voltage exceeded 600mV for the first time, breaking the performance bottleneck of this type of photovoltaic device.
Schematic diagram of Li2SnS3 interface phase regulating metal ion migration
At the same time, the team also systematically explained the internal relationship between "ion migration-defects-performance" from the perspective of material growth mechanism for the first time, forming a systematic theoretical support.
This research result not only provides a new idea for the subsequent research and development of CZTSSe solar cells, but also lays a solid theoretical and technical foundation for its industrial application.