| Abstract
| - Investigation of the growth of CdSe nanocrystals (∼160 atoms) to the uniquely stable size of 2nm allows the monitoring of the crystallization process in semiconductor quantum dots. By using acombination of optical techniques, high-resolution transmission electron microscopy (HRTEM), and powderX-ray diffractometry (XRD), new phenomena were explored during the CdSe nanocrystal growth process,which involved significant morphological reconstruction and crystallization of the initially formed amorphousnanoparticles. During the crystallization, the absorption onset of the CdSe quantum dots blue shifted towardhigher energies at 3 eV (414 nm), while the photoluminescence red shifted to lower energies. Furthermore,an apparent increasing Stokes shift was observed during the formation of small CdSe nanoparticles. Onthe other hand, the photoluminescence excitation spectra showed constant features over the reaction time.Additionally, results from HRTEM and XRD studies show that the CdSe nanoparticles were amorphous atearly reaction stages and became better crystallized after longer reaction times, while the particle sizeremained the same during the crystallization process. These observations demonstrate the important roleof the surface on the optical properties of small CdSe quantum dots and facilitated the spectroscopicmonitoring of the crystallization process in quantum dots.
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