Chinese Academy of Sciences Achieves World Record Efficiency of 15.45% for Kesterite Solar Cell

Why It Matters

By overcoming ion‑migration losses, the record narrows the efficiency gap between kesterite and CIGS, positioning a low‑cost, abundant‑material thin‑film technology for commercial deployment. This could diversify solar supply chains and reduce reliance on scarce elements.

Key Takeaways

• Record 15.45% efficiency for CZTSSe solar cell
• LTS interphase curbs copper, tin, zinc migration
• Open‑circuit voltage exceeds 600 mV at 1.10 eV bandgap
• No rare elements; supply risk minimal
• IP portfolio paves path to industrial scale

Pulse Analysis

Kesterite (Cu₂ZnSn(S,Se)₄) has long been touted as a low‑cost alternative to CIGS because it relies on earth‑abundant copper, zinc, tin and selenium. Despite its material advantages, efficiency has lagged behind CIGS, hovering around 14% in laboratory settings. The new record of 15.45% demonstrates that strategic interface engineering can unlock performance previously thought out of reach, reinforcing kesterite’s relevance as the solar industry seeks to mitigate supply‑chain constraints tied to indium and gallium.

The technical linchpin of the breakthrough is the Li₂SnS₃ (LTS) interphase, which creates a balanced migration environment for cations. By reducing the migration barrier disparity between zinc and tin from 0.41 eV to 0.21 eV, the interphase limits antisite defects and promotes larger, uniform grains. This translates into a higher open‑circuit voltage—over 600 mV—at a modest 1.10 eV bandgap, addressing the long‑standing voltage deficit that hampered kesterite cells. The strategy also curbs hysteresis and long‑term degradation, key hurdles for commercial viability.

Beyond the laboratory, the achievement carries significant market implications. The accompanying IP portfolio equips manufacturers with a clear pathway to scale the LTS process, potentially accelerating the transition to mass‑production thin‑film modules that rival CIGS in cost per watt. As utility‑scale developers prioritize both price and material security, a commercially ready kesterite technology could reshape solar procurement strategies, diversify the global supply chain, and stimulate further investment in next‑generation photovoltaic research.