Structural, Optical, and Photoluminescence Properties of Cr3+ Ion-Doped ZnO-CdS Nanocomposite

What is it about?

Herein, the influence of trivalent Cr doping on crystal structure, morphology, and optical properties of a ZnO-CdS nanocomposite was studied. X-ray diffraction (XRD) study confirmed the preservation of hexagonal crystal structure of ZnO and CdS with an average grain size of 16 nm. In addition, the lattice cell parameters and internal lattice strain were estimated. Morphological studies and chemical compositional studies were carried out through scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive x-ray spectrophotometry (EDS). UV-vis absorption, electron paramagnetic resonance (EPR), and photoluminescence (PL) spectrophotometry were used to investigate the coordination geometry, bonding nature, and luminescent properties of Cr-doped nanocomposites. The EPR spectrum exhibited a well-resolved signal at g ~ 1.99 arising due to the Cr3+-Cr3+ exchange couple interaction. From the optical absorption study, crystal field parameter (Dq) and Racah parameters (B and C) were calculated as Dq = 1855, B = 450, and C = 3685 cm−1. EPR and UV–vis absorption studies reveal that the Cr3+ ions are positioned in octahedral geometry and bonded covalently with the surrounding ligands. Photoluminescence studies revealed the influence of Cr3+ ions in the ZnO-CdS nanocomposite, an intense emission band at 577 nm corresponding to the transition, 2T2g(F)→4A2g(F). The evaluated correlated color temperature (CCT) of 3562 K signifies yellow emission near warm white light. We believe that these materials will be useful for lighting applications.

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Why is it important?

The influence of trivalent Cr doping on crystal structure, morphology, and optical properties of a ZnO-CdS nanocomposite was studied. X-ray diffraction (XRD) study confirmed the preservation of hexagonal crystal structure of ZnO and CdS with an average grain size of 16 nm. In addition, the lattice cell parameters and internal lattice strain were estimated. Morphological studies and chemical compositional studies were carried out through scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive x-ray spectrophotometry (EDS).

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