CNRL

Firstly, ligand design. We tune the energy level of QD films by varying the surface ligands. By manipulating the strength of the dipole applied to the QD, we can fine-tune the energy level of the QD film. Additionally, we optimize the mobility of QD films by modifying the bulkiness and length of the ligands. Secondly, inorganic core doping. We are developing synthetic methods for doped QDs. Especially, we are focusing on incorporating impurity ions into the QD core during the synthesis stage. The colloidal synthesis is complex, thus well-designed reaction conditions are required. For example, appropriate size and charge of ion, precursor with suitable reactivity, solubility on the reaction solvent, and many other factors critically affect the QD doping. With the successful synthesis of doped QDs, we can control the doping polarity and conductivity of QD films. We are currently exploring this approach on various wavelength ranges. (J. Phys. Chem. C 2023, 127, 9, 4825–4832) 3. Microscopic understanding of the surface of colloidal nanocrystals Nanocrystals possess large surface-to-volume ratios, which make them highly sensitive to their structural, chemical, and electronic environments. The atoms on their surfaces are charge-balanced by surface ligands, but inappropriate ligands can also exhibit structural defects, such as vacancies, under-coordinated or dimerized atoms, which can lead to undesirable properties such as trap states in the band gap etc. The suitable interactions between the surface ligands and the surface can eliminate trap states and tune the absolute energy levels of nanocrystals. Additionally, ligand-surface interactions play a crucial role in determining complementary properties such as dispersibility, stability, and the ability to assemble nanocrystals