Tailoring luminescent and magnetic characteristics of Cu-doped CdSSe quantum dots for optomagnetic applications

ions. Transmission electron microscopy revealed nearly spherical nanoparticles with average sizes increasing from approximately 3.5 to 5.0 nm upon Cu incorporation. The absorption peak exhibits a progressive blue shift, while the optical band gap increases from 2.48 to 2.83 eV as the Cu concentration increases from 0 to 10%. Cu doping creates defect-related radiation centers, leading to strong emission in the long wavelength region. The average lifetime increased sharply from 16.26 ns for undoped CdSSe QDs to 882.57 ns for CdSSe:Cu 10% QDs, demonstrating efficient carrier localization at Cu-related impurity levels. Magnetic measurements revealed that Cu doping significantly altered the magnetism of CdSSe QDs by generating local magnetic moments associated with the 3d state of Cu. This study demonstrates that Cu doping can simultaneously control the luminescence and magnetic properties of CdSSe QDs, making them attractive candidates for advanced optoelectronic and spintronic applications.