Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Microwave-assisted synthesis of water-dispersed CdTe/CdSe core/shell type II quantum dots | Sai and Kong Nanoscale Research Letters 2011 6 399 http content 6 1 399 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Microwave-assisted synthesis of water-dispersed CdTe CdSe core shell type II quantum dots Li-Man Sai and Xiang Yang Kong Abstract A facile synthesis of mercaptanacid-capped CdTe CdSe core shell type II quantum dots in aqueous solution by means of a microwave-assisted approach is reported. The results of X-ray diffraction and high-resolution transmission electron microscopy revealed that the as-prepared CdTe CdSe quantum dots had a core shell structure with high crystallinity. The core shell quantum dots exhibit tunable fluorescence emissions by controlling the thickness of the CdSe shell. The photoluminescent properties were dramatically improved through UV-illuminated treatment and the time-resolved fluorescence spectra showed that there is a gradual increase of decay lifetime with the thickness of CdSe shell. Introduction Semiconducting nanocrystals such as quantum dots QDs have attracted more attention due to their unique optical properties and many potential applications including nanolasers biolabelings and photovoltaics etc. 1 2 . The unique optical properties are featured as narrow emission spectra continuous absorption band high chemical and photobleaching stability and surface functionality. To date QDs have various nanostructured configurations typically as core shell heterostructure QDs where two different semiconductors are incorporated into a single colloidal QD 3 . There are type I and type II core shell QDs with different carrier localizations depending on the band structure offsets between the semiconducting core and the shell 4 . Type I is where both the electrons and holes are confined in the core in contrast type II is where the electrons and holes are separated between the core and the shell giving rise to a significant increase in the exciton lifetime with possible .
