Synthesis of Extremely Small CdSe and Highly Luminescent CdSe/CdS Core–Shell Nanocrystals via a Novel Two‐Phase Thermal Approach

An environmentally harmless method of synthesizing extremely small CdSe and highly luminescent CdSe/CdS core–shell quantum dots (see Figure) with CdSe cores of 1.2–1.5 nm diameter is reported. The CdSe/CdS core–shell quantum dots exhibit 60–80 % quantum yield at room temperature. The emission peak is tunable from 445 to 517 nm (purplish blue to green yellow) by increasing the diameter of the CdSe core and/or the thickness of the CdS shell.