Highly Efficient White‐Light Emission Triggered by Sb³⁺ Dopant in Indium‐Based Double Perovskites

Abstract

Inorganic indium‐based halide double perovskites (DPs) are environmentally friendly alternatives to lead‐based halide perovskites in light‐emitting diodes, but commonly suffer from low quantum efficiency and harsh synthesis conditions. Herein, a large‐scale green method using water as solvent is developed for the synthesis of 3D Cs2NaInCl6 and 0D Cs2InCl5·H2O with/without Sb3+ dopant at room temperature. The transformation between Cs2InCl5·H2O and Cs2NaInCl6 products is controlled by the concentration of eco‐friendly NaCl, where excess Cl− and Na+ ions play important roles in inhibiting In3+ hydrolysis and promoting Cs2NaInCl6 crystallization, respectively. The obtained Cs2NaInCl6:Sb and Cs2InCl5·H2O:Sb exhibit highly luminescent self‐trapped exciton‐related blue (450 nm; photoluminescence quantum yield [PLQY] ≈85%) and yellow (610 nm; PLQY ≈88%) emissions, which are comparable to those obtained by previous methods. Tunable cold/warm white light with a PLQY of up to ≈73% is achieved by the rational assembly of two components with highly overlapped excitation wavelength ranges. Each component demonstrates remarkable stability against humidity and heat. This composite shows great potential in solid‐state lighting for general illumination.

Emission Mechanism of Self-Trapped Excitons in Sb3+-Doped All-Inorganic Metal-Halide Perovskites

“…The crystal structures of the three perovskite-related materials are shown in Figure 1, where Sb 26,43 The as-prepared Rb 3 InCl 6 :Sb 3+ , Cs 2 NaInCl 6 :Sb 3+ , and Cs 2 InCl 5 •H 2 O:Sb 3+ samples showed broadband green, blue, and yellow emission, respectively, and the profiles were consistent with previous reports. 23,42,43 The crystal structures of the obtained samples were characterized by powder X-ray diffraction (Figure S1). The X-ray diffraction patterns of all of the samples were in good agreement with the standard patterns.…”

“…The crystal structures of the three perovskite-related materials are shown in Figure , where Sb 3+ forms [SbCl 6 ] 3– octahedrons in three-dimensional Cs 2 NaInCl 6 and zero-dimensional Rb 3 InCl 6 , and [Sb­(H 2 O)­Cl 5 ] 2– octahedrons in zero-dimensional Cs 2 InCl 5 ·H 2 O. Samples of Rb 3 InCl 6 : Sb 3+ , Cs 2 NaInCl 6 : Sb 3+ , and Cs 2 InCl 5 ·H 2 O: Sb 3+ with a trace amount of the dopant (<0.1% atomic percentage) were synthesized by a previously reported solution method. , The as-prepared Rb 3 InCl 6 : Sb 3+ , Cs 2 NaInCl 6 : Sb 3+ , and Cs 2 InCl 5 ·H 2 O: Sb 3+ samples showed broadband green, blue, and yellow emission, respectively, and the profiles were consistent with previous reports. ,, The crystal structures of the obtained samples were characterized by powder X-ray diffraction (Figure S1). The X-ray diffraction patterns of all of the samples were in good agreement with the standard patterns.…”

Efficient White Photoluminescence from Self-Trapped Excitons in Sb3+/Bi3+-Codoped Cs2NaInCl6 Double Perovskites with Tunable Dual-Emission

“…The yellow emission was also not from Cs 2 InCl 5 •H 2 O impurity or Cs 2 NaInCl 6 host (Figure S4). 40 Similar broadband LE emission centered at 570 nm was observed from Sb 3+ -doped Cs 2 NaInCl 6 , as shown in Figure 2b. It had a similar PLE spectrum to that of the Sb 3+ /Bi 3+ codoped sample for LE emission.…”

“…Facile precipitation was used to prepare Sb 3+ and Bi 3+codoped Cs 2 NaInCl 6 double perovskites, as reported in our previous work (details in Supporting Information). 40 By adjusting the feeding ratio between Sb 3+ and Bi 3+ precursors, a series of microcrystals with varied Sb 3+ and Bi 3+ content was obtained (Figure S2). When Sb 3+ and Bi 3+ were substituted in the In 3+ position, the product retained the Cs 2 NaInCl 6 structure, as demonstrated by powder X-ray diffraction data in Figure 1a.…”

Highly Reversible Cesium Manganese Iodine for Sensitive Water Detection and X-ray Imaging

“…Low-dimensional lead (Pb)-free perovskite derivatives have been attracting increasing interest as environmentally friendly alternatives for use in light-emitting diodes (LEDs), X-ray detectors, photocatalysis, and so on because of their excellent material properties, such as high photoluminescence quantum yields (PLQYs), excellent solution processability, and tunable emission covering the full visible range. − However, most of the metal halide materials exhibit a soft ionic lattice, leading to facile ion migration and/or transformation to undesired phases upon exposure to humidity, heat, and light. − Among various kinds of environmental factors, humidity exerts a very important role in influencing material composition and thus their optical properties. For example, Chen et al reported that the green-emitting Cs 3 InCl 6 :Sb 3+ can be transformed into the orange-emitting Cs 2 InCl 5 ·H 2 O:Sb 3+ upon exposure to moisture .…”