Additive Engineering by 6-Aminoquinoline Monohydrochloride for High-Performance Perovskite Solar Cells

One of the major challenges confronted with perovskite solar cells (PSCs) is reducing the trap-state density and structural defect of perovskite films. Additive engineering is an effective strategy to mitigate this issue. In this work, we introduce an additive, 6-aminoquinoline monohydrochloride (AQCl), with strong electron-donating amino groups, into CsMAFA-based perovskite precursor solution, which suppresses the formation of lead iodide during the perovskite crystallization process through strong interaction with Pb2+ ions. This introduction ameliorates perovskite crystallization, mitigates structural defect and trap-state density, modulates the energy array between the perovskite layer and the hole transport layer, and alleviates nonradiative recombination of charge carriers. The reference PSC device exhibits an efficiency of 19.24%; in contrast to this, the PSC device doped with AQCl in proper concentration obtains a champion efficiency of 21.66%. The results of this simple operating procedure significantly improve performance and demonstrate that additive engineering is beneficial to further optimize the crystallization process of perovskites.