White Light Emission from Zn(II) and DMSO-Induced Copper Nanocluster Assembly

Area of Science:

• Materials Science
• Nanotechnology
• Photochemistry

Background:

• Metal nanoclusters exhibit unique photoluminescence (PL) properties influenced by ligands and environment.
• Tuning PL requires precise control over nanocluster assembly and interactions.

Purpose of the Study:

• To synthesize and characterize dual-emissive copper nanoclusters (Zn-CuNCs).
• To investigate the origin of dual emission and its environmental sensitivity.
• To explore the potential for white light emission (WLE).

Main Methods:

• Synthesis of histidine-stabilized copper nanoparticles (CuNPs) and copper nanoclusters (CuNCs) using 3-mercaptopropionic acid.
• Formation of Zn-CuNCs by adding Zn(II) salt.
• Characterization using temperature-dependent emission spectra, transmission electron microscopy (TEM), and fluorescence anisotropy.
• Modification of emission using dimethyl sulfoxide (DMSO).

Main Results:

• CuNCs showed bluish-green PL (λem=470 nm, QY≈1.8%).
• Zn-CuNCs exhibited dual emission (blue λem=420 nm, red λem=615 nm) with enhanced QY (≈9.1%).
• Blue emission persisted at high temperatures, while red emission vanished; DMSO altered emission intensities and nanocluster compactness.
• Near-perfect WLE achieved with CIE coordinates (0.33, 0.32).

Conclusions:

• Dual emission in Zn-CuNCs likely arises from locally excited states and through-space/Cu(I) interactions.
• Emission properties are sensitive to temperature and solvent environment.
• Zn-CuNCs offer a promising platform for tunable photoluminescence and white light generation.