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

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. ; BMBF, 03SF0540, Nachwuchsgruppe MeSa-Zuma: Entwicklung von spektral optimierten, hocheffizienten und langzeitstabilen Perowskit/Silizium Tandem Solarzellen ; BMWi, 0324288C, Verbundvorhaben: ProTandem - Demonstration der Produktionstauglichkeit von Perowskit-Silizium Tandemsolarzellen; Teilvorhaben: Entwicklung von Kontaktschichten für die Silizium-Heterojunction Bottomzelle ; EC/H2020/763977/EU/Perovskite Thin-film Photovoltaics (PERTPV)/PERTPV ; DFG, 423749265, Identifizierung und Unterdrückung von Grenzflächenrekombination für hocheffiziente Perowskit-Solarzellen ; DFG, 402726906, SPP 2196: Perowskit-Halbleiter: Von fundamentalen Eigenschaften zur Anwendung