Here, the maximum estimate of the carrier density of (NH 3 (CH 2 ) 7 NH 3 ) 2 Sn 3 I 10 is 5.89×10 16 cm -3 ; this is significantly lower than many other tin(II) based perovskites without vacancy order. For example, early reports of CH 3 NH 3 SnI 3 reported metallic conductivity (e.g., degenerate doping) with a carrier concentration of 2 × 10 19 cm -3 . Many strategies exist to reduce the hole concentration by way of preventing tin oxidation and incorporation to the material. A leading chemistry is the inclusion of SnF 2 into growth solutions, as fluoride exhibits a strong preference for Sn(IV) to stay in solution. Yet, incorporation of SnF 2 into a growth solution for (CH(NH 2 ) 2 )SnI 3 film growth only brings the carrier density down from 2.2 × 10 20 cm -3 (no SnF 2 ) to 7.2 × 10 18 cm -3 (15% SnF 2 ). Given that our measurements reflect the maximum possible carrier density, vacancy ordering is an effective way to suppress the formation of equilibrium mobile charge carrier.