2020-09-01
Lattice Compression Increases the Activation Barrier for Phase Segregation in Mixed-Halide Perovskites
Publication
Publication
ACS Energy Lett. , Volume 5 - Issue 10 p. 3152- 3158
The bandgap tunability of mixed-halide perovskites makes them promising candidates for light emitting diodes and tandem solar cells. However, illuminating mixed-halide perovskites results in the formation of segregated phases enriched in a single-halide. This segregation occurs through ion migration, which is also observed in single-halide compositions, and whose control is thus essential to enhance the lifetime and stability. Using pressure-dependent transient absorption spectroscopy, we find that the formation rates of both iodide- and bromide-rich phases in MAPb(BrxI1-x)3 reduce by two orders of magnitude on increasing the pressure to 0.3 GPa. We explain this reduction from a compression-induced increase of the activation energy for halide migration, which is supported by first-principle calculations. A similar mechanism occurs when the unit cell volume is reduced by incorporating a smaller cation. These findings reveal that stability with respect to halide segregation can be achieved either physically through compressive stress or chemically through compositional engineering.
Additional Metadata | |
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ACS | |
The Netherlands Organisation for Scientific Research (NWO) | |
doi.org/10.1021/acsenergylett.0c01474 | |
ACS Energy Lett. | |
Organisation | Hybrid Solar Cells |
Muscarella, L., Hutter, E., Wittmann, F., Woo, Y. W., Jung, Y.-K., McGovern, L., … Ehrler, B. (2020). Lattice Compression Increases the Activation Barrier for Phase Segregation in Mixed-Halide Perovskites. ACS Energy Lett., 5(10), 3152–3158. doi:10.1021/acsenergylett.0c01474 |