DOI: https://doi.org/10.29363/nanoge.sus-mhp.2022.028
Publication date: 15th November 2022
The consequences of ionic migration represent one of the major bottlenecks in the achievement of real large-scale and stable commercial perovskite solar cells. These consequences include slow kinetic phenomena such as hysteretic responses, coupled with light-induced accumulation capacitance and negative capacitance, directly affecting photovoltage values.1 As dopants in the bulk or at the interfaces, alkali metals have proven to be good allies in the race to mitigate the perovskite ionic migration or its effects.2 However, the exact role of the alkali in each case still need to be clarified. In this work, we have use Li, Na and K as doping agents at the ESL/PVK interface. We have found that the beneficial effects lie in a modulation of the migrating ions depending on the ionic size of the alkali dopant. The analysis through impedance spectroscopy and time-resolved photoluminescence, among others, clarify the reasons behind an outstanding photovoltage up to 1.65 V achieved for pure MAPbBr3 PSCs.