Photoluminescence of Singlet/Triplet Self‐Trapped Excitons in Sb³⁺‐Based Metal Halides

Abstract

these alternatives with varied crystal structures improved the water/thermal stability and optimized the optical performance of metal halide materials group. [7] ns 2 metal ion-based metal halides have always been regarded as the mainstream materials owing to their excellent optical properties and the facile synthesis procedure. [8] Moreover, ns 2 metal ion-based halides with broad-band emission and large Stokes shift, which can avoid selfabsorption effectively, are desirable for phonic applications. And, the self-trapped excitons (STEs) herein are ascribed to the strong electronphonon coupling in the distorted excited structure. [9] To generate diverse STEs emission in the visible light region, different ns 2 metal ions like Ge 2+ , Sn 2+ , Te 4+ , Bi 3+ , and Sb 3+ are selected to adjust emission peaks due to their different coordination environment and special crystal/local structures. [10] Among ns 2 metal halides, Sb 3+ -based halides with blue, green, and red tunable luminescence have been explored extensively as low-toxic and highly stable candidates, moreover, their luminescence mechanisms are discussed by combined experimental and theoretical methods, as well as their unique singlet and triplet excitonic emission. [5d,e,11] In this review, we first look back the electronic energy levels of ground state and excited state for ns 2 ions and the luminescence of Sb 3+ in transition metal oxides. Next, we summarize the recent progresses of the crystal structures, optical properties, and luminescence mechanisms of some Sb 3+ -based halides and Sb 3+ -doped metal halides including all-inorganic and hybrid organic-inorganic perovskite derivatives. Then, we discuss the current achievements of these materials in the emerging applications. And finally, we offer the perspective and some suggestions on the possible development of luminescent Sb 3+ -based metal halides. Electronic Energy Levels of Sb 3+The luminescence and radiation process of ns 2 ions in solidstate compounds have been widely investigated. [10a,b,d,12] A free Emerging lead-free metal halides with low toxicity and unparalleled optoelectronic properties have attracted growing research interests, also demonstrating extensive application potentials. Among these, Sb 3+ -based allinorganic/organic-inorganic hybrid metal halides become a vital group due to the special energy level distribution along with diverse optical properties. However, there remains a gap in understanding the relationship between the crystal structure and the radiation process of involved Sb 3+ emission. Herein, the existing reports about Sb 3+ -based luminescent metal halides are revisited and their structure-luminescence-application relationship is explored, and it is further established that the triplet self-trapped excitons (STEs) emission of Sb 3+ varies in different crystallographic environments and endows tunable luminescent performance. This work aims to provide constructive strategies in the further exploitation of Sb 3+ -based metal halides, and also guides the structura...

Crystalline‐Phase‐Recognition‐Induced Domino Phase Transition and Luminescence Switching for Advanced Information Encryption

“…3 P 1 (360 nm) transition, respectively. [13,14] These are consistent with the photoluminescence excitation (PLE) spectra shown in Figure 2a,b.T he yellow emission of 1 has abroadband peaking at 575 nm, while the orange emission of 2 is located at 615 nm under the excitation of 350 nm or 370 nm. Additionally,both 1 and 2 have asmall shoulder peak around 400 nm under higher-energy excitation ranging from 280 to 320 nm (Figure S6).…”

Red-Emissive Nanocrystals of Cs4MnxCd1-xSb2Cl12 Layered Perovskite

“…The PLE behavior resembles that of absorption, indicating that the excitation occurs through the Sb 3+ bands. Interestingly, even if Sb 3+ is known for having optical emission in metal halides, 25,26 we did not detect any PL signal in Cs4CdSb2Cl12, whereas the 4 T1 → 6 A1 transition of Mn 2+ induced the red emission in all the other samples. We explain this behavior by an energy transfer between antimony(III) and manganese(II) ions, Sb 3+ → Mn 2+ .…”

“…24 Sb 3+ is a ns 2 ion characterized by the 1 S0 ground state and four higherenergy levels denoted as 3 P0, 3 P1, 3 P2 and 1 P1. 25 The absorption in the 300 -400 nm span can be ascribed to the partially allowed 1 S0 → 3 P1 transition, commonly named as the A band, split into a doublet; similarly, the allowed 1 S0 → 1 P1 transition (Cband) is responsible for the absorption signal found at ~ 270 nm. 11,19,25 Instead, the d → d Mn 2+ transition, generally observed for Mn-based materials between All the Cs4MnxCd1-xSb2Cl12 compositions, except for x = 0, show a red emission centered at around 620-650 nm under UV excitation (Figure S6b).…”

“…25 The absorption in the 300 -400 nm span can be ascribed to the partially allowed 1 S0 → 3 P1 transition, commonly named as the A band, split into a doublet; similarly, the allowed 1 S0 → 1 P1 transition (Cband) is responsible for the absorption signal found at ~ 270 nm. 11,19,25 Instead, the d → d Mn 2+ transition, generally observed for Mn-based materials between All the Cs4MnxCd1-xSb2Cl12 compositions, except for x = 0, show a red emission centered at around 620-650 nm under UV excitation (Figure S6b). The photoluminescence excitation (PLE) shape spectra exhibit an intense peak centered at ~325 nm with a shoulder at ~285 nm (Figure 2b).…”

Structural Dimensionality Modulation toward Enhanced Photoluminescence Efficiencies of Hybrid Lead‐Free Antimony Halides

“…[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.…”