Triple-junction perovskite/silicon solar cells reach 32.2% certified efficiency

A research team has demonstrated a perovskite/perovskite/silicon triple-junction solar cell with a certified steady-state power conversion efficiency of 32.22% on a 1.046 cm² aperture area. The same architecture achieved 26.97% on a larger 15.62 cm² aperture, with negligible hysteresis between forward and reverse voltage scans.

The advance addresses two long-standing bottlenecks in wide-bandgap perovskite sub-cells: non-radiative recombination at surfaces and interfaces, and sub-optimal current matching across the three junctions. The researchers introduced a passivating molecule, 4F-POEABr, whose ammonium group and electron-deficient structure provide both chemical and field-effect passivation.

This treatment raised the quasi-Fermi-level splitting of the wide-bandgap perovskite film to 1.53 eV and delivered an open-circuit voltage of 1.413 V in the top sub-cell. In parallel, the team engineered a tailored tin oxide/indium zinc oxide bilayer to manage optical interference, boosting the current density of the current-limited middle sub-cell by 0.5 mA cm⁻².

Robust interconnection layers and engineered perovskite interfaces further improved operational stability and reduced device-to-device variation. The certified efficiencies were measured under standard test conditions at an accredited laboratory.

Triple-junction designs stack three light-absorbing layers to capture a broader slice of the solar spectrum than single-junction cells, offering a theoretical path beyond the Shockley–Queisser limit of roughly 33% for single junctions. Perovskite/silicon tandems have already exceeded 33%, but adding a third junction pushes the practical ceiling higher.

The work demonstrates a synergistic strategy that simultaneously tackles voltage losses in the top cell and current losses in the middle cell. The researchers note that the approach is compatible with scalable fabrication methods, though the paper does not specify a timeline for commercial deployment.

Further gains will require continued reduction of non-radiative losses in all sub-cells and refinement of large-area uniformity. The reported 26.97% efficiency on a 15.62 cm² aperture represents a step toward module-scale performance.