Publication Type
Journal
Journal Name
ACS Applied Energy Materials
Publication Date
Page Numbers
1298 to 1304
Volume
3
Issue
2
Abstract
We report charge recombination rates in lead iodide perovskites with alloys of formamidinium (FA) and methylammonium (MA) cations, FAxMA1–xPbI3, 0 ≤ x ≤ 0.9, prepared through ion exchange with minimal differences in morphology and charge trap density. Our results show that the trap-mediated recombination rate increases over 2 orders of magnitude with decreasing MA content. These results are consistent with a proposed mechanism that MA molecules are more effective in screening charged defects. In contrast, band-to-band charge recombination rates are minimized at an intermediate alloy composition. These findings reveal that the monovalent cations impact recombination processes through different mechanisms.
