Phase transition, optical, and elastic properties of a new hybrid organic–inorganic perovskite: [(R)-(+)-3-aminoquinuclidine]KI3

A new hybrid organic–inorganic perovskite, (R-3AQ)KI3 [R-3AQ2+ = (R)-(+)-3-aminoquinuclidine], has been synthesized and comprehensively characterized by experimental approaches and density functional theory calculations. Our experimental results demonstrate that (R-3AQ)KI3 has a typical perovskite structure and exhibits a reversible order–disorder phase transition at temperatures of 457 and 443 K on heating and cooling, respectively. Under ultraviolet irradiation, a clear yellowish-green emission peaked at 556 nm was observed for (R-3AQ)KI3. The calculated electronic structure shows that (R-3AQ)KI3 possesses a typical direct bandgap with a value of 3.74 eV and its valence band maximum and conduction band minimum primarily arise from the I-5p and I-5s orbitals, respectively. In addition, the elastic calculations indicate that (R-3AQ)KI3 displays a relatively large structure stiffness, relatively small elastic anisotropy, and fairly low acoustic velocity, owing to the rigid K–I bonds and the strong hydrogen bond interactions between the [KI3]2− perovskite framework and R-3AQ2+ cations. These results suggest that the mechanical robustness of this multifunctional (R-3AQ)KI3 makes it a good candidate material for sensing applications.