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Monolithic perovskite/silicon tandem solar cell with >29% efficiency by enhanced hole extraction

Al-Ashouri, Amran; Köhnen, Eike; Li, Bor; Magomedov, Artiom; Hempel, Hannes; Caprioglio, Pietro; Márquez, José A.; Morales-Vilches, Anna Belen; Kasparavicius, Ernestas; Smith, Joel A.; Phung, Nga; Menzel, Dorothee; Grischek, Max; Kegelmann, Lukas; Skroblin, Dieter; Gollwitzer, Christian; Malinauskas, Tadas; Jošt, Marko; Matič, Gašper; Rech, Bernd; Schlatmann, Rutger; Topič, Marko; Korte, Lars; Abate, Antonio; Stannowski, Bernd; Neher, Dieter; Stolterfoht, Martin; Unold, Thomas; Getautis, Vytautas; Albrecht, Steve

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.
Published in: Science, 10.1126/science.abd4016, American Association for the Advancement of Science (AAAS)