Cyan Emission in Two-Dimensional Colloidal Cs₂CdCl₄:Sb³⁺Ruddlesden–Popper Phase Nanoplatelets

Abstract

Metal halide perovskites are one of the most investigated materials in optoelectronics, with their lead-based counterparts being renowned for their enhanced optoelectronic performance. The 3D CsPbX3 structure has set the standard with many studies currently attempting to substitute lead with other metals while retaining the properties of this material. This effort has led to the fabrication of metal halides with lower dimensionality, wherein particular 2D layered perovskite structures have captured attention as inspiration for the next generation of colloidal semiconductors. Here we report the synthesis of the Ruddlesden–Popper Cs2CdCl4:Sb3+ phase as colloidal nanoplatelets (NPs) using a facile hot injection approach under atmospheric conditions. Through strict adjustment of the synthesis parameters with emphasis on the ligand ratio, we obtained NPs with a relatively uniform size and good morphological control. The particles were characterized through transmission electron microscopy, synchrotron X-ray diffraction, and pair distribution function analysis. The spectroscopic characterization revealed most strikingly an intense cyan emission under UV excitation with a measured PLQY of ∼20%. The emission was attributed to the Sb3+-doping within the structure.

Bright Green Emission from Self-Trapped Excitons Triggered by Sb3+ Doping in Rb4CdCl6

“…This lifetime value is also comparable to the previously reported Cs 2 CdCl 4 :Sb 3+ . 50 The lifetime for Rb 4 CdCl 6 host at 77 K monitored at 330 nm is mono-fitted with the value of 11.32 ns indicating the fluorescent nature (Figure S10). Thus, this emission at 330 nm may be ascribed to the emission from the STE singlet state.…”

Green Triplet Self-Trapped Exciton Emission in Layered Rb3Cd2Cl7:Sb3+ Perovskite: Comparison with RbCdCl3:Sb3+

“…A certain gap still exists in its practical application. As a general rule, using other inorganic materials instead of toxic lead materials and reducing the structural dimensions can greatly reduce toxicity while improving stability. − Moreover, dopants as an efficient method could easily tune the emission bands of these crystals because of the additional energy levels in the host lattice, in addition to the excitons that maintain customizable energies. , The Sb-doping in perovskites is a unique strategy to expand the compositional space of perovskite materials, often changing their optical and electronic properties in ways unattainable with undoped materials. − In different cadmium halides, such as from Cs 3 Cd 2 Cl 7 and Cs 2 CdCl 2 Br 2 to Cs 7 Cd 3 Br 3 , Sb-doping can tune the emission from cyan to orange . Furthermore, we doped Sb in the low-dimensional RbCdCl 3 material to exhibit a photoluminescence quantum yield of 91.7% for yellow emission .…”

Efficient Orange Emission in Mn2+-Doped Cs3Cd2Cl7 Perovskites with Excellent Stability

“…However, there are relatively few reports on the research of RP-phased Cs 3 Cd 2 Cl 7 . 23 The RP-phase perovskite Cs high-power electronics. However, the material's low PLQY forces us to improve its luminescent properties.…”

“…19 Specifically, each Cd atom coordinates with 6 Cl atoms to form [CdCl 6 ] 4− octahedrons, which are angularly shared along the ab plane and separated by Cs atoms in the c-axis direction, alternating with each other. 23 After the introduction of Mn 2+ ions, [MnCl 6 ] 4− can partially replace the [CdCl 6 ] 4− octahedron because Mn 2+ and Cd 2+ have similar ligand properties. The schematic structure diagram of the Mn 2+ :Cs 3 Cd 2 Cl 7 unit cell is illustrated in Figure 1a.…”

“…These advantages contribute to improved moisture and thermal stability. , Meanwhile, Cd-based perovskites play an important role in the perovskite family and have been widely studied for their outstanding optoelectronic properties, such as the existing various studies on Cs 2 CdCl 4 and its application in optoelectronic devices. However, there are relatively few reports on the research of RP-phased Cs 3 Cd 2 Cl 7 . The RP-phase perovskite Cs 3 Cd 2 Cl 7 has a bandgap of 4.35 eV, which is a rare ultrawide-bandgap material for applications including deep ultraviolet optoelectronics and high-power electronics.…”