Zero-dimensional (0D) hybrid metal halides with unique compositional and structural tunability appear as an emerging class of luminescent materials, but near-infrared (NIR) emitters therein are largely unexplored to date. This study presents three novel 0D hybrid antimony chlorines with edge-sharing [Sb 2 Cl 8 ] 2À dimers, showing unusual room-temperature broadband NIR emission with the maximum emission wavelength up to 1070 nm. Photoluminescence studies and density functional theory calculation demonstrate that the emissions originate from the highly localized excitons, and that the confined [Sb 2 Cl 8 ] 2À dimers in these structures show low symmetry and a large degree of structural freedom. These hybrid antimony chlorines with [Sb 2 Cl 8 ] 2À dimers expand the range of new NIR materials in 0D metal halides.

Ge-based hybrid perovskite materials have demonstrated great potential for second harmonic generation (SHG) due to the geometry and lone-pair induced non-centrosymmetric structures. Here, we report a new family of hybrid 3D Ge-based bromide perovskites AGeBr 3 , A = CH 3 NH 3 (MA), CH(NH 2 ) 2 (FA), Cs and FAGe 0.5 Sn 0.5 Br 3 , crystallizing in polar space groups. These compounds exhibit tunable SHG responses, where MAGeBr 3 shows the strongest SHG intensity (5 × potassium dihydrogen phosphate, KDP). Structural and theoretical analysis indicate the high SHG efficiency is attributed to the displacement of Ge 2 + along [111] direction and the relatively strong interactions between lone pair electrons of Ge 2 + and polar MA cations along the c-axis. This work provides new structural insights for designing and fine-tuning the SHG properties in hybrid metal halide materials.

Zero‐dimensional (0D) hybrid metal halides, which consist of organic cations and isolated inorganic metal halide anions, have emerged as phosphors with efficient broadband emissions. However, these materials generally have too wide bandgaps and thus cannot be excited by blue light, which hinders their applications for efficient white light‐emitting diodes (WLEDs). The key to achieving a blue‐light‐excitable 0D hybrid metal halide phosphor is to reduce the fundamental bandgap by rational chemical design. In this work, we report two designed hybrid copper(I) iodides, (Ph3MeP)2Cu4I6 and (Cy3MeP)2Cu4I6, as blue‐light‐excitable yellow phosphors with ultrabroadband emission. In these compounds, the [Cu4I6]2− anion forms an I6 octahedron centered on a cationic Cu4 tetrahedron. The strong cation–cation bonding within the unique cationic Cu4 tetrahedra enables significantly lowered conduction band minimums and thus narrowed bandgaps, as compared to other reported hybrid copper(I) iodides. The ultrabroadband emission is attributed to the coexistence of free and self‐trapped excitons. The WLED using the [Cu4I6]2− anion‐based single phosphor shows warm white light emission, with a high luminous efficiency of 65 lm W−1 and a high color rendering index of 88. This work provides strategies to design narrow‐bandgap 0D hybrid metal halides and presents two first examples of blue‐light‐excitable 0D hybrid metal halide phosphors for efficient WLEDs.