Principles of melting in hybrid organic-inorganic perovskite and polymorphic ABX 3 structures.

Four novel dicyanamide-containing hybrid organic-inorganic ABX 3 structures are reported, and the thermal behaviour of a series of nine perovskite and non-perovskite [AB(N(CN) 2 ) 3 ] (A = (C 3 H 7 ) 4 N, (C 4 H 9 ) 4 N, (C 5 H 11 ) 4 N; B = Co, Fe, Mn) is analyzed. Structure-property relationships are investigated by varying both A-site organic and B-site transition metal cations. In particular, increasing the size of the A-site cation from (C 3 H 7 ) 4 N → (C 4 H 9 ) 4 N → (C 5 H 11 ) 4 N was observed to result in a decrease in T m through an increase in Δ S f . Consistent trends in T m with metal replacement are observed with each A-site cation, with Co < Fe < Mn. The majority of the melts formed were found to recrystallise partially upon cooling, though glasses could be formed through a small degree of organic linker decomposition. Total scattering methods are used to provide a greater understanding of the melting mechanism.