halide perovskites (LDHPs), the optically active inorganic blocks are separated and surrounded by insulating organic components with intrinsic quantum confinement effects, which readily leads to firmly confined bound excitons in the metal halide species under photo excitation. Simultaneously, the strong electronquantum coupling transiently localizes the excitons along with excited-state structural deformation, which produces selftrapped excitons (STE) with lower excited state energy. [4] Therefore, the bulk LDHPs always display strongly Stokes-shifted broadband light emissions, which are different from the narrow emission bands of 3D halide perovskites. [5] These distinctive luminescent performances endow LDHPs with a series of unique applications complementary to the 3D perovskites in solid-state lighting, X-ray scintillation, remote thermometry, and thermography, especially for white light emitting diodes (WLEDs). [6] Among all the PL qualities, PL quantum yield (PLQY) is one of the most important indicators for optoelectronic applications of hybrid halide perovskites. To achieve higher PLQY and more desirable luminescence performance, substantial optically active centers based on ns 2 electronic configuration of valence shell have been explored including Sn 2+ , Ge 2+ , Pb 2+ , Bi 3+ , and Sb 3+ . [7][8][9] In these fascinating hybrid metal halides, the 5s 2 metal halides readily occupy the maximum of emission efficiency owing to the unique expressed structural distortion level induced by the out shell lone pair. [10] Simultaneously considering the instabilities of Sn 2+ and Ge 2+ halides, toxicity of Pb 2+ , metal as well as low efficiencies of Bi 3+ phases, green 5s 2 Sb 3+ based hybrid metal halides are deemed to be one of most promising ultrabroadband luminescent materials with higher PLQYs and oxidation resistance abilities. [7b,8a,11] Up to now, the PLQYs of 0D hybrid antimony halides based on discrete [SbX 5 ] 2− and [SbX 6 ] 3− units can reach up to near unity due to strong quantum confinement effect. [12] These outstanding PL properties intrigued further in-depth understanding the enhancement or modulating mechanism of PLQY for hybrid antimony halides from molecular design level, which is also greatly desirable for subsequent rational design of new high-performance hybrid halides. Rationally optimizing the photoluminescence performance via accurate structural modulation is one of most important and challenging issues for hybrid halides. Herein, a viable crystal dimensional reduction strategy is proposed to reasonably enhance the photoluminescence quantum yield (PLQY) of hybrid antimony halide. Specifically, a synthetic technique is developed and new 1D [DMPZ]SbCl 5 • H 2 O (DP-SbCl 5 ) is sliced to 0D [DMPZ] 2 SbCl 6 • Cl • (H 2 O) 2 (DP-SbCl 6 ) with crystal dimensional reduction from infinite [SbCl 5 ] 2− chain to discrete [SbCl 6 ] 3− octahedron. Comparing with nonluminescent 1D DP-SbCl 5 , 0D DP-SbCl 6 displays highly efficient broadband yellow light emission with enhanced PLQY up to 75.94%. ...

Pursuit of high-performance blue light emitting perovskite have attracted intensive attention due to insufficient photoluminescence quantum yield (PLQY) of <5% for CsPbCl3, which far lag behind the near-unit PLQYs (>90%)...

Recently, 2D organic–inorganic hybrid lead halide perovskites have attracted intensive attention in solid‐state luminescence fields such as single‐component white‐light emitters, and rational optimization of the photoluminescence (PL) performance through accurate structural‐design strategies is still significant. Herein, by carefully choosing homologous aliphatic amines as templates, isotypical perovskites [DMEDA]PbCl4 (1, DMEDA=N,N‐dimethylethylenediamine) and [DMPDA]PbCl4 (2, DMPDA=N,N‐dimethyl‐1,3‐diaminopropane) having tunable and stable broadband bluish white emission properties were rationally designed. The subtle regulation of organic cations leads to a higher degree of distortion of the 2D [PbCl4]2− layers and enhanced photoluminescence quantum efficiencies (<1 % for 1 and 4.9 % for 2). The broadband light emissions could be ascribed to self‐trapped excitons on the basis of structural characterization, time‐resolved PL, temperature‐dependent PL emission, and theoretical calculations. This work gives a new guidance to rationally optimize the PL properties of low‐dimensional halide perovskites and affords a platform to probe the structure–property relationship.