Designing Guanidine-Based Antimony Halides Luminescence Perovskite Crystals toward Near-Unity Quantum Yield

Design of lead-free zero-dimensional organic–inorganic metal halide luminescent (OIMHs) materials is critical due to their structure diversity and excellent photophysical characteristics for solid-state lighting application. However, the choice of suitable organic molecules is a very tricky issue. Herein, a novel zero-dimensional (0D) hybrid metal halide with the composition (gua-DPG)3SbCl6 (gua-DPG = 1,3-diphenylguanidine) has been obtained by introducing guanidinium derivatives (Gua) as templates organic cations into the inorganic metal halide frameworks. Benefiting from Gua possessing fruitful supramolecular interaction sites, the Gua-based hybrid metal halide can be regarded as perfect host–guest structures, in which the inorganic metal halides [SbCl6]3– octahedron anionic units are periodically embedded in the wide-bandgap organic Gua cations matrix, which is favorable for designing metal halide luminescent materials. The prepared (gua-DPG)3SbCl6 exhibits a single broadband yellow emission at 584 nm arising from self-trapped exciton (STEs) emission and with a near-unity quantum yield. In addition, the new luminescent compound exhibits excellent stability. Interestingly, using (gua-DPG)3SbCl6 as a yellow phosphor, highly stable white-light-emitting diodes (WLEDs) were demonstrated. These results highlight the potential of guanidinium molecules acting as a type of versatile organic cation in the development of luminescent materials with intriguing optical properties and indicate that (gua-DPG)3SbCl6 is a promising candidate for solid-state lighting applications.