McGovern Lucie, Koschany Isabel, Grimaldi Gianluca, Muscarella Loreta A, Ehrler Bruno
Center for Nanophotonics, AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands.
J Phys Chem Lett. 2021 Mar 11;12(9):2423-2428. doi: 10.1021/acs.jpclett.1c00205. Epub 2021 Mar 4.
Ion migration in perovskite layers can significantly reduce the long-term stability of the devices. While perovskite composition engineering has proven an interesting tool to mitigate ion migration, many optoelectronic devices require a specific bandgap and thus require a specific perovskite composition. Here, we look at the effect of grain size to mitigate ion migration. We find that in MAPbBr solar cells prepared with grain sizes varying from 2 to 11 μm the activation energy for bromide ion migration increases from 0.17 to 0.28 eV. Moreover, we observe the appearance of a second bromide ion migration pathway for the devices with largest grain size, which we attribute to ion migration mediated by the bulk of the perovskite, as opposed to ion migration mediated by the grain boundaries. Together, these results suggest the beneficial nature of grain engineering for reduction of ion migration in perovskite solar cells.
钙钛矿层中的离子迁移会显著降低器件的长期稳定性。虽然钙钛矿成分工程已被证明是减轻离子迁移的一种有效手段，但许多光电器件需要特定的带隙，因此需要特定的钙钛矿成分。在此，我们研究了晶粒尺寸对减轻离子迁移的影响。我们发现，在制备的晶粒尺寸从2到11μm不等的MAPbBr太阳能电池中，溴离子迁移的活化能从0.17 eV增加到0.28 eV。此外，我们观察到对于晶粒尺寸最大的器件出现了第二条溴离子迁移路径，我们将其归因于由钙钛矿本体介导的离子迁移，而不是由晶界介导的离子迁移。总之，这些结果表明晶粒工程对于减少钙钛矿太阳能电池中的离子迁移具有有益作用。
