Strain-activated light-induced halide segregation in mixed-halide perovskite solids

Zhao Y, Miao P, Elia J, Hu H, Wang X, Heumüller T, Hou Y, Matt G, Osvet A, Chen YT, Tarragó M, de Ligny D, Przybilla T, Denninger P, Will J, Zhang J, Tang X, Li N, He C, Pan A, Meixner AJ, Spiecker E, Zhang D, Brabec C (2020)

Publication Type: Journal article

Publication year: 2020


Book Volume: 11

Article Number: 6328

Issue: 1

DOI: 10.1038/s41467-020-20066-7


Light-induced halide segregation limits the bandgap tunability of mixed-halide perovskites for tandem photovoltaics. Here we report that light-induced halide segregation is strain-activated in MAPb(I1−xBrx)3 with Br concentration below approximately 50%, while it is intrinsic for Br concentration over approximately 50%. Free-standing single crystals of CH3NH3Pb(I0.65Br0.35)3 (35%Br) do not show halide segregation until uniaxial pressure is applied. Besides, 35%Br single crystals grown on lattice-mismatched substrates (e.g. single-crystal CaF2) show inhomogeneous segregation due to heterogenous strain distribution. Through scanning probe microscopy, the above findings are successfully translated to polycrystalline thin films. For 35%Br thin films, halide segregation selectively occurs at grain boundaries due to localized strain at the boundaries; yet for 65%Br films, halide segregation occurs in the whole layer. We close by demonstrating that only the strain-activated halide segregation (35%Br/45%Br thin films) could be suppressed if the strain is properly released via additives (e.g. KI) or ideal substrates (e.g. SiO2).

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Zhao, Y., Miao, P., Elia, J., Hu, H., Wang, X., Heumüller, T.,... Brabec, C. (2020). Strain-activated light-induced halide segregation in mixed-halide perovskite solids. Nature Communications, 11.


Zhao, Yicheng, et al. "Strain-activated light-induced halide segregation in mixed-halide perovskite solids." Nature Communications 11 (2020).

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