Material Design and Optoelectronic Properties of Three-Dimensional Quadruple Perovskite Halides

The discovery of
new halide perovskite-type structures could favor
the exploration of optoelectronic materials, as in the case of double
perovskites applied in solar cells, light-emitting diodes, and X-ray
detectors. In this work, we propose a strategy for designing quadruple
perovskites by heterovalent cation transmutation from double perovskites.
Two stable quadruple perovskite halides, i.e., Cs4CdSb2Cl12 and Cs4CdBi2Cl12, with a vacancy-ordered three-dimensional (3D) crystal structure
were predicted through symmetry analysis and density functional theory
(DFT) calculations. The title perovskite halides are also electronically
3D with direct forbidden bandgaps. Following the indication provided
by the DFT results, Cs4CdSb2Cl12 and
Cs4CdBi2Cl12 as unique quadruple
perovskites were successfully synthesized by a solvothermal method.
The steady-state photoluminescence (PL) shows wide emission, while
the transient PL exhibits carrier recombination lifetime on the order
of microseconds at low temperature. The quadruple perovskite halides
provide an alternative platform for promising optoelectronic material
design in addition to simple and double perovskites.