Controllable synthesis of perovskite solid solutions as novel energetic materials via thermodynamic equilibrium.

Perovskite solid solutions have aroused interest in energy applications, owing to the capability of fine-tuning and enhancing performance to surpass ternary perovskites. Their synthesis, however, is hard to control in solution due to the intricate self-assembly process wherein components crystallize in undetermined ratios. Herein, we present a facile approach to the controllable synthesis of perovskite solid solutions in aqueous solution and develop perovskite solid solutions as a novel class of energetic materials for the first time. Specifically, the composition control of perovskite solid solutions is achieved through thermodynamic equilibrium of reaction crystallization in water, exhibiting a linear relationship with the natural logarithm of reactant concentrations. Based on Goldschmidt's rule, we design a general formula of energetic perovskite solid solutions as (H2dabco)(NH4)(1-x)M x (ClO4)3, in which 0 < x < 1, H2dabco2+ refers to 1,4-diazabicyclo[2.2.2]octane-1,4-diium, and M is a quaternary ion. The as-synthesized (H2dabco)(NH4)(1-x)(Na) x (ClO4)3 exhibits exceptional thermal stability, outperforming its ternary perovskite prototypes, and the prepared (H2dabco)(NH4)(1-x)Ag x (ClO4)3 manifests energy-safety optimization as elevated energy levels with improved mechanical sensitivity. This work not only exploits perovskite solid solutions as a novel class of energetic materials with promising properties but also provides a means for controllably synthesizing perovskite solid solutions for versatile advanced applications.