Abstract:
Colloidal quasi-two-dimensional cadmium chalcogenide nanoplatelets have attracted
considerable interest due to their narrow excitonic emission and absorption bands, making them
promising candidates for advanced optical applications. In this study, the synthesis of quasi-twodimensional CdSe NPLs with a thickness of 3.5 monolayers was investigated to understand the
effects of synthesis temperature on their stoichiometry, morphology, and optical properties. The
NPLs were synthesized using a colloidal method with temperatures ranging from 170 ◦C to 210 ◦C
and optimized precursor ratios. Total reflection X-ray fluorescence (TXRF) analysis was employed to
determine stoichiometry, while high-resolution transmission electron microscopy (HRTEM) and UVVis spectroscopy and photoluminescence spectroscopy were used to analyze the structural and optical
characteristics. The results showed a strong correlation between increasing synthesis temperature
and the enlargement of nanoscroll diameters, indicating dynamic growth. The best results in terms of
uniformity, stoichiometry, and optical properties were achieved at a growth temperature of 200 ◦C.
At this temperature, no additional optical bands associated with secondary populations or heteroconfinement were observed, indicating the high purity of the sample. Samples synthesized at lower
temperatures exhibited deviations in stoichiometry and optical performance, suggesting the presence
of residual organic compounds.
