Triple-junction perovskite solar cells have demonstrated a maximum efficiency of around 20% to date. This level was recently surpassed by an international research team reporting development of a device with a new record efficiency of 24.3% and an open-circuity voltage of 3.21 V.

The U.S. National Renewable Energy Laboratory certified the quasi-steady-state efficiency for this solar cell as 23.3%.

Tests were initially conducted with a perovskite composed of cesium, lead, tin, iodine, bromine and small organic molecules; a top layer incorporated mixed halide perovskites with a high proportion of bromineThe device posted a new record efficiency of 24.3% and an open-circuity voltage of 3.21 V. Source: University of Toronto and iodine. Phases with elevated bromine concentrations were observed to separate from those with elevated iodine content under bombardment of high-frequency photons, resulting in an increase in defects and degraded cell performance.

Application of solid-state magnetic resonance spectroscopy to simulate the effect of altering material composition revealed that replacing the organic molecules for an all-inorganic perovskite structure and replacing cesium with rubidium suppressed light-induced phase separation.

As reported in Nature, the resulting triple-junction cells retained 80% of their initial efficiency following 420 hours of operation at the maximum power point. Researchers from University of Toronto (Canada), University of Warwick (U.K.), Northwestern University, King Abdullah University of Science and Technology (Saudi Arabia), University of North Carolina at Chapel Hill, The University of Toledo and Yunnan University (China) contributed to this development.