Broadband and high diffuse reflectivity of hollow mesoporous silica nanospheres and their UV light shielding ability for light-labile peroxides

We herein report the optical diffuse reflection properties of hollow mesoporous silica nanospheres (HMSNs). The HMSNs reflect more than 90% of the UV and visible light in the wide range of 240–800 nm and more than 70% of the UV light shorter than 240 nm, which are significantly higher than that of the bulk silica. The high reflectance of the HMSNs mainly arises from multiple scattering, which is caused by the disordered arrangement of nanospheres with thickness up to several hundred nanometers. Besides, the unique microstructure of HMSNs and the comparable size of HMSNs with UV light may also contribute to their high reflection according to the Mie scattering principles. Unlike semiconductor materials which shield UV light by absorbing UV light and generating reactive species, the HMSNs display extremely low absorption in the UV light region. The high UV light reflection properties as well as the specific hollow mesoporous structures of the HMSNs indicate their superior applications in UV light shielding devices.