The carrier mobility assessed by TRMC is generally low in contrast to the lower limited estimated from the Hellwarth polaron model. These trends are consistent for the three vacancy-ordered tin-based materials studied: (NH 3 (CH 2 ) 7 NH 3 ) 2 Sn 3 I 10 , µ Hellwarth = 40-54 TRMC ΦΣµ = 1.45 cm 2 V -1 s -1 ; (CH 3 NH 3 ) 2 SnI 6 , µ Hellwarth = 52 cm 2 V -1 s -1 , TRMC ΦΣµ = 9.1×10 -3 cm 2 V -1 s -1 . TRMC typically underestimates the carrier mobility due to the time-dependent mobility from polaron formation or multiple trapping. For example, previous Hall measurements on cold-pressed powder pellets yielded mobilities of 9 and 2.5 cm 2 V -1 s -1 for Cs 2 SnI 6 and (CH 3 NH 3 ) 2 SnI 6 , respectively. Thus, the TRMC-determined mobility µ AC of (NH 3 (CH 2 ) 7 NH 3 ) 2 Sn 3 I 10 reflects a lower bound of the "true" value related to carrier diffusion lengths and the preserved trend in mobilities across the different compounds reflects the polaronic nature of mobile charge carriers. Moreover, especially in cases where the intrinsic mobility is high, carrier confinement effects due, to limited crystalline grain size can easily depress µ AC further. However, given the large particle sizes observed in scanning electron microscopy images (Figure ; sizes spanning 85 to 135 µm, centered at 108 µm), these confinement effects are unlikely to play in limiting the mobility here.