Monolithic perovskite/silicon tandem solar cell with >29% efficiency by enhanced hole extraction
Amran Al‐Ashouri, Eike Köhnen, Bor Li, Artiom Magomedov, Hannes Hempel, Pietro Caprioglio, J.A. Marquez, Anna Belen Morales‐Vilches, Ernestas Kasparavičius, Joel A. Smith, Nga Phung, Dorothee Menzel, Max Grischek, Lukas Kegelmann, Dieter Skroblin, Christian Gollwitzer, Tadas Malinauskas, Marko Jošt, Gašper Matič, B. Rech, Rutger Schlatmann, Marko Topič, Lars Korte, Antonio Abate, Bernd Stannowski, Dieter Neher, Martin Stolterfoht, Thomas Unold, Vytautas Getautis, Steve Albrecht
Abstract
Tandem solar cells that pair silicon with a metal halide perovskite are a promising option for surpassing the single-cell efficiency limit. We report a monolithic perovskite/silicon tandem with a certified power conversion efficiency of 29.15%. The perovskite absorber, with a bandgap of 1.68 electron volts, remained phase-stable under illumination through a combination of fast hole extraction and minimized nonradiative recombination at the hole-selective interface. These features were made possible by a self-assembled, methyl-substituted carbazole monolayer as the hole-selective layer in the perovskite cell. The accelerated hole extraction was linked to a low ideality factor of 1.26 and single-junction fill factors of up to 84%, while enabling a tandem open-circuit voltage of as high as 1.92 volts. In air, without encapsulation, a tandem retained 95% of its initial efficiency after 300 hours of operation.