Hysteresis in centrosymmetric CuPbI₃perovskite halide: apolar dielectric or orientable dielectric?

We demonstrated the change in polarization behaviour at the surface/interface before and after light through Havriliak-Negami equation of lesser known CuPbI₃. We have synthesized CuPbI₃through cold sintering technique and the polarization mechanisms are altered by increasing (cold) sintering temperature. The structure of CuPbI₃was not known and we predicted it to be hexagonal (R3̄m) with 21R prototype representation. The hysteresis is reported to be affected by ferroelectricity (reorientable dipoles with non-centrosymmetry), to inspect this a centrosymmetric CuPbI₃is taken. In spite of centrosymmetry, we observed that the hysteresis area and shape ofIVcurve in AM 1.5 G sunlight shows the drastic variation with the change in polarization behaviour. Our experimental results suggest that apolar dielectric behaviour is the cause ofI-Vhysteresis rather than robust ferroelectric polarization (which was absent in the present case).