Highly Luminescent Copper(I) Halide Phosphors Encapsulated in Fumed Silica for Anti‐Counterfeiting and Color‐Converting Applications

Abstract

Os(II) complexes given the low price, minor environmental pollution, and abundant resource of copper. [1][2][3][4][5][6][7][8][9][10][11][12][13] Owing to the rich coordination chemistry of Cu(I) ions, their combination with organic and inorganic ligands often leads to a large structural diversity, ranging from discrete molecular 0D to 1D chains, and from 2D layers to extended 3D networks. [14][15][16][17][18] Generally, luminescent Cu(I) hybrid materials can be synthesized via the reaction of CuX with organic nitrogen, phosphorus, and sulfur ligands in organic solvents. [19][20][21] The inorganic and organic components may connect via covalent bond, ionic bond, or coordination action. [22][23][24][25] The overall performance of the complexes can be systematically tuned by changing the reactants and reaction conditions, yielding a broad range of physical and chemical properties, such as the optical, electronic, catalytic, or sensing. [26][27][28][29][30][31] However, most synthesis methods are undertaken in harmful and flammable organic solvents, including acetone, acetonitrile, dimethylformamide, etc. Recently, some researchers reported the mechanochemical synthesis of luminescent Cu(I) hybrid materials by mechanical grinding without a solvent, or in the presence of a slight amount of assisting solvent to initiate the ligand exchange reaction. [32,33] However, a considerable amount of solvent needs to be used to purify the product. Meanwhile, the resultant products usually show poorer optical properties than those synthesized by the traditional solution methods. Additionally, the obtained luminescent composites tend to aggregate to form large particles, which are inconvenient for further applications.Although aqueous processed synthesis has drawn more and more attention following the requirement of sustainable development, there are rare reports about the aqueous synthesis of luminescent Cu(I) hybrid materials. Recently, Yao et al. prepared the high-green-emission Cu 4 I 6 (pr-ted) 2 /polyvinylpyrrolidone (PVP) ink (pr-ted: 1-propyl-1,4-diazabicyclo[2.2.2]octan-1-ium) via the one-pot synthesis in water/ethanol solution, where PVP played a key role in confining the Cu 4 I 6 (pr-ted) 2 clusters in nanoscale. [34] However, the process involves ethanol and the ink is green emission only. The aqueous synthesis of Luminescent Cu(I) hybrid materials are currently receiving increasing attention due to their rich photophysical properties with promising phosphors applications. However, the complex synthesis processes usually involving chemotoxic organic solutions largely hinder their practical applications. Herein, the authors introduce the highly luminescent copper(I) halide phosphors encapsulated in fumed silica synthesized via aqueous mechanochemical process. By using different precursors, they obtain blue, green, and orange emission copper(I) halide phosphors with high photoluminescence quantum yields. The green emission is owing to the formation of the well-known 0D (18-crown-6) 2 Na 2 (H 2 O) 3 Cu 4 I 6 (CNCI), whil...

Synthesis of Efficient and Stable Tetrabutylammonium Copper Halides with Dual Emissions for Warm White Light‐Emitting Diodes

“…It is well-known that tunable luminescence is very essential for various applications of Cu I hybrid materials. [38] Encouraged by the dual-emission luminescence performance, we then demonstrated this material application for LED. Firstly, without modulating various phosphors, WLED device can be constructed just through encapsulating the powder (mixing with 25 % polystyrene (PS)-methylbenzene solution) on a violet InGaN light chip (Figure 8a).…”

Manipulation of the ratio of Li+/Zn2+ on the structure and persistent luminescence property of Li2Zn0.9992Ge3O8:0.08%Cr3+

“…It is worth exploring that the intensity of the TL spectra in the low‐temperature region (peak 1) is quickly reduced as the temperature increases, whereas the TL spectra intensity in the high‐temperature region (peak 2) slowly decreases and moves toward the high‐temperature region. In Figure 4D, the trap depth is analyzed using the initial ascent method, which assumes a constant concentration of carriers trapped in the low‐temperature side of the TL spectra, which can be expressed by the kinetic equation 9,37,45 : $$$$\begin{equation}{I_t} = A\exp \left( {\frac{{ - {E_t}}}{{KT}}} \right)\end{equation}$$$$where $${I_t}$$ is the intensity of TL spectra, A represents the constant, including the frequency factors, K is the Boltzmann constant, and $${E_t}$$ is trap depth. It is demonstrated that the trap depth variations range between 0.307 and 1.246 eV, and the detailed data are shown in Figure S13 and Table S4, where all the trap depths can be well fitted as straight lines by fitting, which proves the existence of two continuously distributed trap energy levels in the material (Figure 4D).…”

“…It is worth exploring that the intensity of the TL spectra in the low-temperature region (peak 1) is quickly reduced as the temperature increases, whereas the TL spectra intensity in the high-temperature region (peak 2) slowly decreases and moves toward the high-temperature region. In Figure 4D, the trap depth is analyzed using the initial ascent method, which assumes a constant concentration of carriers trapped in the low-temperature side of the TL spectra, which can be expressed by the kinetic equation 9,37,45 :…”

“…It is known that additional defects will be created to balance the internal charges of nonequivalent substitutions (Figure 5A,E-G). 21,45 When Zn 2+ is substituted by Cr 3+ :…”

Zero-dimensional Cu(i)-based organometallic halide with green cluster-centred emission for high resolution X-ray imaging screens

“…1d, revealing a broadband absorption peak with a range of 300–500 nm, which can be seen in similar Cu( i ) metal halides. 7,14–16 The PL spectrum with an excitation wavelength of 420 nm demonstrates broadband emission centred at 527 nm. Note that the emission spectra obtained at different wavelengths (270 and 420 nm) and different temperatures (80 and 300 K) are almost identical (Fig.…”