The commonly-used superstrate configuration (depositing front subcell first and then depositing back subcell) in all-perovskite tandem solar cells is disadvantageous for long-term stability due to oxidizable narrow-bandgap perovskite assembled last and easily exposable to air. Here we reverse the processing order and demonstrate all-perovskite tandems in a substrate configuration (depositing back subcell first and then depositing front subcell) to bury oxidizable narrow-bandgap perovskite deep in the device stack. By using guanidinium tetrafluoroborate additive in wide-bandgap perovskite subcell, we achieve an efficiency of 25.3% for the substrate-configured all-perovskite tandem cells. The unencapsulated devices exhibit no performance degradation after storage in dry air for 1000 hours. The substrate configuration also widens the choice of flexible substrates: we achieve 24.1% and 20.3% efficient flexible all-perovskite tandem solar cells on copper-coated polyethylene naphthalene and copper metal foil, respectively. Substrate configuration offers a promising route to unleash the commercial potential of all-perovskite tandem solar cells.

全钙钛矿串联太阳能电池中常用的覆板配置（先沉积前子电池，然后沉积后子电池）由于最后组装的可氧化窄带隙钙钛矿且容易暴露于空气中，因此不利于长期稳定性。在这里，我们颠倒了处理顺序，并演示了基板配置中的全钙钛矿串联（首先沉积后子电池，然后沉积前子电池），以将可氧化的窄带隙钙钛矿深埋在器件堆栈中。通过在宽带隙钙钛矿子电池中使用四氟硼酸胍添加剂，我们实现了基板配置的全钙钛矿串联电池的25.3%的效率。未封装的器件在干燥空气中储存 1000 小时后性能没有下降。基板配置也拓宽了柔性基板的选择：我们在镀铜聚乙烯萘和铜金属箔上分别实现了 24.1% 和 20.3% 的柔性全钙钛矿串联太阳能电池效率。基板配置为释放全钙钛矿串联太阳能电池的商业潜力提供了一条有前途的途径。