Toward simple and environmentally friendly fabrication of luminescent and water-soluble Fe:CdS nanocrystals

• A simple and environmentally friendly strategy for fabricating highly luminescent Fe:CdS nanocrystals is proposed.
• Tunable optical properties can be realized with different ligand/Cd molar ratios.
• This strategy may open a new synthetic avenue for fabricating functional nanocrystals with excellent properties.

Herein, we demonstrate a simple and environmentally friendly strategy for fabricating luminescent and water-soluble Fe:CdS nanocrystals, which tailors their optical properties by altering the ligand/Cd molar ratio. The Fe:CdS nanocrystals crystallize well, and have cubic sphalerite structure, and the obvious broadening of diffraction peaks is ascribed to their small size nature. The presence of thioglycollic acid on the surface of Fe:CdS nanocrystals was confirmed by the FTIR spectroscopy. The absorption edges of the resulting nanocrystals are blue-shifted compared with the corresponding bulk band gap of CdS, indicating the quantum confinement effect. The molar ratio of ligand/Cd plays a crucial role in determining their final optical properties, and the underlying mechanism for their tunable optical properties is also elucidated. As a consequence, the current investigation not only shows the optical properties of the resulting nanocrystals are simply achieved and experimentally regulated, but also provides a useful synthetic route for producing water-soluble and highly fluorescent nanocrystals with tunable optical properties.