*3.1.2. Extrinsic electrical properties:*

The techniques used to measure the electrical parameters are given in subsections.

#### *3.1.2.1. Impedance spectroscopy (IS) [115, 116]*

This technique is used to identify the frequency dependence of capacitance, to measure charge diffusion lengths and lifetimes and to investigate carrier trapping and recombina‐ tion. The carrier diffusion length was derived and has been estimated to be about ~1 μm for CH3 NH3 PbI3−*<sup>x</sup>* Cl*<sup>x</sup>* [83].
