Colloidal Synthesis and Optical Properties of All‐Inorganic Low‐Dimensional Cesium Copper Halide Nanocrystals

Abstract

Low-dimensional metal halides have recently attracted extensive attention owing to their unique structure and photoelectric properties.H erein, we report the colloidal synthesis of all-inorganic low-dimensional cesium copper halide nanocrystals (NCs) by adopting ah ot-injection approach.U sing the same reactants and ligands,b ut different reaction temperatures,b oth 1D CsCu 2 I 3 nanorods and 0D Cs 3 Cu 2 I 5 NCs can be prepared. Density functional theory indicates that the reduced dimensionality in 1D CsCu 2 I 3 compared to 0D Cs 3 Cu 2 I 5 makes the excitons more localized, which accounts for the strong emission of 0D Cs 3 Cu 2 I 5 NCs. Subsequent optical characterization reveals that the highly luminescent, strongly Stokes-shifted broadband emission of 0D Cs 3 Cu 2 I 5 NCs arises from the self-trapped excitons.O ur findings not only present am ethod to control the synthesis of low-dimensional cesium copper halide nanocrystals but also highlight the potential of 0D Cs 3 Cu 2 I 5 NCs in optoelectronics. Scheme 1. Colloidal synthesis of cesium copper halide nanocrystals.Supportinginformation and the ORCID identification number for one of the authors of this article can be found under: https://doi.

0D Cs3Cu2X5 (X = I, Br, and Cl) Nanocrystals: Colloidal Syntheses and Optical Properties

“…The PL emission features of Cs 3 Cu 2 X 5 NCs can be attributed to the STE emission. The PLE spectra monitored at different emission wavelengths display identical shapes and features, confirming that these PL emissions derive from the relaxation of the same excited states (Figure S9, Supporting Information) . For STE emission, the emission energy is not only related to the bandgap, but also depends on the exciton binding energy, lattice distortion energy and self‐trapping energy, as illustrated in Figure c .…”

“…In particular, Cu atoms are fourfold coordinated with halide ions to form tetrahedral structure, which favors the Jahn–Teller distortion to produce strong STE emission . Although the synthesis and optical properties of 0D Cs 3 Cu 2 I 5 NCs have been reported, it is still challenging to prepare high‐quality colloidal NCs of 0D all‐inorganic copper(I) halides materials with isostructural series (such as Cs 3 Cu 2 X 5, X = I, Br, and Cl), and systematically investigate their halogen‐dependent optical properties. Herein, we present the colloidal syntheses and optical characterizations of Cs 3 Cu 2 X 5 (X = I, Br, and Cl) NCs.…”

Synthesis, Crystal Structure and Photoelectric Response of All‐Inorganic Copper Halide Salts CsCuCl3

“…And the structure of organic‐inorganic LHSs can be easily destroyed by moisture and heat, resulting in poor stability of the photoelectronic device. Thus, it is necessary to develop a high‐performance, low‐cost, corrosion‐resistant all‐inorganic and lead‐free metal halide salts (MHS) , . Numerous researchers developed alternative lead‐free MHS materials in the recent years .…”

Doped Zero‐Dimensional Cesium Zinc Halides for High‐Efficiency Blue Light Emission

“…Meanwhile, the absence of characteristic Cu II satellite peak at around 943 eV also rules out the presence of Cu 2+ oxidation state. [13] As the electron configurations of Cu I d 10 and Cu II d 9 are different, [14] we further measured the electron paramagnetic resonance (EPR) spectra of Cs 2 ZnBr 4 :Cu to exclude the presence of unpaired electrons of copper. As we expected, no EPR signal was observed (Supporting Information, Figure S4), thus confirming that copper is incorporated in Cs 2 ZnBr 4 as Cu + .…”