Extended Data Fig. 10: Estimating O2 permeability using Thiele modulus.
From: A molecularly impermeable polymer from two-dimensional polyaramids
(A) Schematic of 2DPA-1-coated MAPbI3 perovskite with defined coordinate system. The top of the 2DPA-1 surface (x = 0) is exposed to ambient O2 and H2O, conflated as reactant G in the model at an ambient concentration of CG0. The perovskite volume, V, has an interface with the polymer at x = δ, with pristine (Phase A – left) and degraded (Phase B – right) phases. The interfacial concentration of reactant G is CGδ. The thickness of 2DPA-1 and perovskite phases are δ and γ, respectively. (B) Perovskite degradation kinetics from the XRD peak ratio of the intrinsic MAPbI3 and PbI2 phases. The left panel is the uncoated perovskite with pseudo-first order rate constant k = 10−5 s−1 while the right panel shows the 2DPA-1-coated perovskite kinetic rate constant k = 7 × 10−7 s−1.
