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Caption : figure s1. the normalized spectrum of permittivity measured under frequencies at 111 hz, 316 hz, 626 hz and 1111 hz. the sample were treated by oxygen exposure.

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Caption : figure s2. the dl measurement for (a) mai, and (b) pbi2.

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Caption : figure s3. the xrd result for perovskite treated with variation condition.

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Caption : figure s4. top-view of scanning electron microscopy images of (a) pristine, (b) water vapor, (c) oxygen and (d) water-oxygen exposed perovskite films. the scale bar is 200 nm.

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Caption : figure s5. (a) pb 4f, (b) i 3d, (c) n 1s and (d) o1s core level spectra of the perovskite films before and after water-oxygen exposure.