Efficient and stable perovskite-silicon tandem solar cells through contact displacement by MgFx

The performance of perovskite solar cells with inverted polarity (p-i-n) is still limited by recombination at their electron extraction interface, which also lowers the power conversion efficiency (PCE) of p-i-n perovskite-silicon tandem solar cells. A MgFx interlayer with thickness of similar to 1 nanometer at the perovskite/C-60 interface favorably adjusts the surface energy of the perovskite layer through thermal evaporation, which facilitates efficient electron extraction and displaces C-60 from the perovskite surface to mitigate nonradiative recombination. These effects enable a champion open-circuit voltage of 1.92 volts, an improved fill factor of 80.7%, and an independently certified stabilized PCE of 29.3% for a monolithic perovskite-silicon tandem solar cell similar to 1 square centimeter in area. The tandem retained similar to 95% of its initial performance after damp-heat testing (85 degrees C at 85% relative humidity) for >1000 hours.