Tailoring the Dimensionality of Metal Halides for Applications in Anticounterfeiting and High-Efficiency White Light-Emitting Diodes.

Organic-inorganic hybrid metal halides (OIHMHs) have garnered significant attention for their exceptional photophysical properties and structural diversity. Zero-dimensional (0D) metal halides are particularly promising for anticounterfeiting and solid-state lighting (SSL) due to their outstanding optical properties and stability. However, achieving precise control over the synthesis of low-dimensional OIHMHs (LD-OIHMHs) remains challenging. This study reports the controlled synthesis of Cd-based OIHMHs, achieving structural dimensionality reduction from 1D to 0D through the strategic embedding of hydrated protons. The 0D structure exhibits an enhanced quantum confinement effect, leading to highly efficient luminescence. Furthermore, Sb doping was employed to incorporate optically active centers, resulting in broadband yellow photoluminescence with a large Stokes shift originating from triplet self-trapped excitons in Sb-centered octahedra. The different luminescence properties of these Cd-based materials were successfully applied in anticounterfeiting. Additionally, a high-performance white light-emitting diode (WLED) was fabricated using the 0D 10% Sb-doped Cd-based material as a phosphor, achieving a color rendering index of 90.8 and a luminous efficiency of 43 lm/W, confirming its potential for SSL applications. This work demonstrates an effective strategy for the dimensional and optical engineering of LD-OIHMHs.