Microwave-based conductivity experiments reveal the equilibrium doping density and photogeneration of mobile carriers in (NH 3 (CH 2 ) 7 NH 3 ) 2 Sn 3 I 10 . As previously discussed, a finite element electromagnetic model was used to fit and analyze the microwave cavity response in the absence of visible light to extract the steady-state complex dielectric response, where the conductivity is defined by σ = ϵ ′′ r (ωϵ 0 ) + iϵ ′ r (ωϵ 0 ). The relative dielectric permittivity extracted from the dark microwave conductivity experiments (Figure ) is