Chemistry in the Molten State: Opportunities for Designing and Tuning the Emission Properties of Halide Perovskites.

A series of monolayered lead halide hybrid perovskites (HOC(CH)NH)PbX, named (C)PbX ( = 4-6, X = Cl, Br), exhibiting a low congruent melting temperature () ( = 130 °C for (C4)PbBr), high stability in the molten state, and whitish type emission, are reported. From the synthesis in the molten state, rare solid solutions of mixed organic cations (CC')PbX (, ' = 4-6; X = Cl, Br; 0 ≤ ≤1) as well as solid solutions of mixed halides (C)Pb(XX') ( = 4-6; X, X' = Cl, Br; 0 ≤ ≤1) have been prepared and characterized (thermal behavior, powder X-ray diffraction (PXRD), photoluminescence properties). The impact of substitutions is significant on the thermal properties, lowering the down to 100 °C for (C4)Pb(BrCl).