Al-Ashouri, A.; Köhnen, E.; Bor, L.; Magomedov, A.; Hempel, H.; Caprioglio, P.; Márquez, J.; Morales Vilches, A.B.; Kasparavicius, E.; Smith, J.A.; Phung, N.; Menzel, D.; Grischek, M.; Kegelmann, L.; Skroblin, D.; Gollwitzer, C.; Malinauskas, T.; Jošt, M.; Matic, G.; Rech, B.; Schlatmann, R.; Topic, M.; Korte, L.; Abate, A.; Stannowski, B.; Neher, D.; Stolterfoht, M.; Unold, T.; Getautis, V.; Albrecht, S.: Monolithic perovskite/silicon tandem solar cell with >29% efficiency by enhanced hole extraction. Science 370 (2020), p. 1300-1309
10.1126/science.abd4016
Open Access Version
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.