Controlling the structure of halide perovskites through component engineering, and thus revealing the changes in luminescence properties caused by the conversion of crystal structure, is of great significance. Herein, we report a controllable synthetic strategy of threedimensional (3D) Cs 2 KInCl 6 and zero-dimensional (0D) (Cs/ K) 2 InCl 5 (H 2 O) halide perovskites by changing the Cs/K feed ratio. 3D Cs 2 KInCl 6 double perovskites are obtained at the Cs/K feed ratio of 1:1, while 0D (Cs/K) 2 InCl 5 (H 2 O) perovskites are formed at the Cs/K feed ratio of 2:1. Further, a reversible crystal structure transformation between 3D Cs 2 KInCl 6 double perovskites and 0D (Cs/K) 2 InCl 5 (H 2 O) perovskites can be achieved by subsequent addition of metal-salt precursors. In addition, the emission efficiency of two perovskite structures can be greatly boosted by breaking the forbidden transition through Sb doping, and as a result, a novel green/yellow reversible emission switch is generated. Meanwhile, the relationship between perovskite structure and luminescence mechanism has been systematically revealed. These environmentally stable halide perovskites have great potential to be applied in optoelectronic devices.

The rich phase structures of perovskite derivatives have attracted extensive attention and can be applied in the fields of optoelectronics due to their high emission efficiency and tunable emission. Herein, we explored a phase-selective solution synthetic route to obtain different Cd-based perovskite derivatives. First, the pristine tetragonal Cs 7 Cd 3 Br 13 was obtained by a solvothermal method, and its photoluminescence quantum yield (PLQY) was boosted from 8.28% to 57.62% after appropriate Sb 3+ doping. Furthermore, halogen substitution was adopted to modify Sb:Cs 7 Cd 3 Br 13 and produced a series of Cd-based perovskite derivatives with different crystal structures and tunable emission from cyan to orange (517−625 nm). The mechanisms behind such experimental phenomena were further investigated and discussed on the basis of material characterization and theoretical computation. This study presented an effective strategy to synthesize bright Cd-based perovskite derivatives with different structures and modulated emission, and it also provided insights to understand the structure/emission modulation via halogen substitution.

Low-dimensional metal halides are attractive for applications in photodetectors, solid-state lighting, and solar cells, but poor stability is an obstacle that must be overcome in commercial applications. Herein, we successfully synthesized a Ruddlesden−Popper (RP)phased perovskite Mn 2+ :Cs 3 Cd 2 Cl 7 with high photoluminescence quantum yield (PLQY) and outstanding thermal and environmental stability by a solvothermal method. The pristine sample Cs 3 Cd 2 Cl 7 exhibits a weak cyan broad emission centered at 510 nm with a low PLQY of ∼4%. Once Mn 2+ ions are introduced into the host lattice, a bright orange emission peaking at 580 nm with a high PLQY of ∼74% was achieved, which is attributed to the efficient energy transfer from the host to Mn 2+ ions and thus results in the 4 T 1 → 6 A 1 radiation transition of Mn 2+ ions. The photoluminescence (PL) intensity and environmental stability of Mn 2+ :Cs 3 Cd 2 Cl 7 can be further improved through A-site Rb alloying. Finally, an orange LED with outstanding color stability was fabricated on the basis of the Mn 2+ :Cs 3 Cd 2 Cl 7 . Our work successfully elucidates that dopant plays an integral role in tailoring optical properties.

Substantial progress has been made in light-emitting diodes (LEDs) based on red- and green-emitting lead halides. However, reducing lead toxicity of emissive materials and achieving the high-efficiency blue-emitting LED beads...

Lead based mental halides are widely investigated and applied in many fileds such as light emitting diodes (LED), Photovoltaic devices, sensor and solar cells etc. for their superior optical properties....