Record 34% Tandem Solar Cell Boosts Efficiency

Record 34% Tandem Cell Sets New Benchmark

The new perovskite‑silicon tandem solar cell developed by Longi and Soochow University reaches a certified 34.0% power conversion efficiency, the highest reported for a two‑terminal tandem under standard test conditions.

How the ZrO₂ Interlayer Improves Performance

By inserting a discontinuous monoclinic ZrO₂ nanoparticle layer between the transparent conductive oxide and the SAM, the researchers suppress non‑radiative recombination and prevent charge leakage while keeping charge extraction efficient. The high‑dielectric‑constant ZrO₂ also reduces interfacial charge accumulation, which mitigates hysteresis.

Performance Numbers

Under AM1.5G illumination the tandem delivers 34.0% efficiency, a 1.997 V open‑circuit voltage (certified 2.014 V), 20.36 mA cm⁻² short‑circuit current and an 83.6 % fill factor. The cell retains 84 % of its initial efficiency after 2 000 h, compared with a control cell that fell to 70 % after 1 000 h.

Stability Gains

The ZrO₂ scaffold creates covalent Zr‑O‑P bonds that anchor the SAM, leading to homogeneous coverage and fewer high‑conductivity hotspots, which translates into the observed long‑term stability.

What It Means for Israel

If Israeli installers adopt 34 % tandem modules, the required roof area per kWp would be substantially lower than with typical 20 % silicon panels. Using the typical central‑Israel yield of 1 700 kWh kWp⁻¹ year⁻¹, a 10 kWp rooftop could generate ~17 000 kWh year⁻¹. At the residential tariff of ₪0.48 /kWh this electricity is worth ~₪8 160 year⁻¹, and with a typical install cost of ₪3 150 /kWp the simple payback remains around 3.9 years, now achieved with a much smaller roof footprint.

Future Outlook

The dual‑anchored ZrO₂ interfacial design could become a standard for commercial tandem production, accelerating the move toward even higher efficiencies and supporting Israel’s 30 % renewable electricity target for 2030.