A joint team of researchers led by Professor Federico Rosei at the Institut national de la recherche scientifique (INRS), and Dr. Riad Nechache from École de technologie supérieure (ÉTS), both located in Montreal, Canada, have developed a composite perovskite thin film made of two different inorganic oxide materials that significantly improves the performance of solar cells.

The team demonstrated a cell in which the open-circuit voltage and short-circuit photocurrent are tunable by varying the electrical resistance of the device, which in turn is controlled by externally applying voltage pulses. This provides an alternative way of achieving highly stable, high-efficiency conversion.

The researchers developed this material which combines two crystal phases comprising the atomic elements bismuth, manganese, and oxygen. The combination of phases optimizes this material's ability to absorb solar radiation and transform it into electricity. The results are highly promising for the development of future solar technologies, and also potentially useful in other optoelectronic devices.

It is the interfaces (grain boundaries) between the BiMnO 3 and BiMn 2O5 crystal phases that play a crucial role in converting more sunlight into electricity. This provides a power conversion efficiency of up to 4.2%, which is said by the team to be a record value for this class of materials, although other organic perovskites tandem cells have shown 26% efficiency.

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