Tuning the UV absorbing ability of CeO2 nanoparticles with F− doping

Ultraviolet (UV) absorbing material is the key to achieving high performance UV shielding device. Because of the large absorption ability on UV light and excellent long-term stability under UV irradiation, CeO2 nanoparticle is considered potential UV absorber for practical applications. However, the CeO2 related materials still face challenges since its UV absorbing capability is non-adjustable, which is unable to meet the changing requirement. In this work, we obtain serial CeO2 nanoparticles with tunable UV absorbing ability through F− doping. Using un-doped CeO2 nanoparticles with size of about 6 nm as starting material and trifluoroacetic acid as F− source, serial F− doped CeO2 marked as CeO2:F1, CeO2:F2, CeO2:F3 and CeO2:F4 are obtained through a post- fluorination strategy. The F− doping rarely changes the size of CeO2, but obviously changes the optical absorbing ability. As the F− content increases, the optical absorption band of the F− doped nanoparticles gradually shifts to short wavelength. Because of the highest F− content, CeO2:F4 sample displays the greatest blue shift with an absorption band of 345 nm. Calculation result reveals that the introduction of F− enlarges the energy band gap of CeO2, leading to the blue shift of the UV absorption band. Finally, serial coated glasses with tunable UV shielding ability are prepared. Using CeO2 nanoparticles or F− doped CeO2 nanoparticles as UV absorber, the optical absorption band of coated glasses could be tuned between 380 nm and 345 nm.