Guanidinium substitution-dependent phase transitions, ionic conductivity, and dielectric properties of MAPbI3.

Despite the proven enhancement of MAPbI3 optoelectronic properties and stability by guanidinium substitution, divergences persist regarding fundamental knowledge on this system. This work shows that GAxMA1-xPbI3 solid solutions have guanidinium content-dependent phase transitions, dielectric permittivities, ionic conductivities, activation energies, and relaxation times.