Silicene Quantum Dots Confined in Few-Layer Siloxene Nanosheets for Blue-Light-Emitting Diodes

Abstract

Two-dimensional silicon-based materials have unique physical and chemical properties due to high surface area and quantum confinement effects. Herein, a topochemical reaction method is used for preparing silicene quantum dots confined in few layer siloxene nanosheets with FeCl 3 •6H 2 O as oxidant, which shows a thickness less than 2 nm. The experimentally prepared siloxene nanosheets are dispersible, with silicene quantum dots having an average diameter less than 5 nm. The silicene quantum dots are self-organized through the oxidation of FeCl 3 , showing unique optical properties of blue emission. The UV−visible absorption and PL emission spectra indicate the quasi-direct band gap transition to the emission. Besides, the few-layer siloxene nanosheets with silicene quantum dots have a radiative lifetime of 1.098 ns at an emission wavelength of 435 nm, which derives from the quasi-direct band transition of silicene quantum dots. Such twodimensional nanosheets of silicon possess potential applications for the emitting layer materials of blue light-emitting diodes (LED).

Fe2+/Fe3+ Cycling for Coupling Self‐Powered Hydrogen Evolution and Preparation of Electrode Catalysts

“…In addition, the acidic electrolyte in the anode chamber was blue‐green colored at the start and then gradually became yellow after long‐term electrolysis under a high current density (Figure S21), implying Fe 3+ production from Fe 2+ OR. Encouragingly, the Fe 3+ ions in the electrolyte after Fe 2+ OR can serve as an oxidant to synthesize SXNS [20] . As shown in Figure 5d, as‐prepared multilayered SXNS (ML SXNS) exhibits an accordion‐like microstructure, and a high‐quality and almost transparent nanosheet morphology of SXNS can be obtained by ultrasonicating the ML SXNS (Figure 5e).…”

“…The vibrational peaks of SiÀ O and SiÀ H are no longer present in the Raman spectra of Fe 2 + OR-derived SXNS (Figure S23b), probably due to the partial reduction of SiÀ OH and SiÀ H bonds in this electrolyte. [20] In addition, the Si 2p spectra show the presence of typical SiÀ Si (100.5 eV) and SiÀ O (103.4 eV) bonds (Figure S24a), and the high-resolution scans of Ca 2p and Fe 2p (Figure S24c, d) show no signals for Ca and Fe, revealing the complete removal of the Ca layer and the absence of residual Fe ions. The above result verifies the feasibility of SXNS synthesis by Fe 3 + RR using the Fe 3 + from the anolyte.…”

Quantum Dots and Their Applications: What Lies Ahead?

“…Silicene QDs confined in few-layer siloxene nanosheets with FeCl 3 •6H 2 O are suggested for potential applications as emitters in blue-light-emitting diodes. 10 Halide-exchanged CsPb(Br/I) 3 and CsPbI 3 QDs showed enhanced structural and optical properties and can be applied to LEDs with 670 nm emission. 11 CsPbBr 3 QDs can also be used to decorate ZnO nanorods on GaN films to provide dual-wavelength green-light-emitting diodes.…”

“…Different materials are used to obtain QDs emitting in specific spectral ranges. Silicene QDs confined in few-layer siloxene nanosheets with FeCl 3 ·6H 2 O are suggested for potential applications as emitters in blue-light-emitting diodes . Halide-exchanged CsPb­(Br/I) 3 and CsPbI 3 QDs showed enhanced structural and optical properties and can be applied to LEDs with 670 nm emission .…”

Formation of the Inorganic and Organic Shells on the Surface of CdSe Quantum Dots

“…As mentioned in the review of Cotta, many commercial applications are available, and it is particularly true for QDs incorporated in display technology . There are different QDs that are known as materials for a tunable spectral range of LEDs. − …”