TY - JOUR AU - Wang, Jinhua AU - Song, Bin AU - Tang, Jiali AU - Hu, Guyue AU - Wang, Jingyang AU - Cui, Mingyue AU - He, Yao PY - 2020 TI - Multi-modal anti-counterfeiting and encryption enabled through silicon-based materials featuring pH-responsive fluorescence and room-temperature phosphorescence JO - Nano Research SN - 1998-0124 SP - 1614 EP - 1619 VL - 13 IS - 6 AB - Optical silicon (Si)-based materials are highly attractive due to their widespread applications ranging from electronics to biomedicine. It is worth noting that while extensive efforts have been devoted to developing fluorescent Si-based structures, there currently exist no examples of Si-based materials featuring phosphorescence emission, severely limiting Si-based wide-ranging optical applications. To address this critical issue, we herein introduce a kind of Si-based material, in which metal-organic frameworks (MOFs) are in-situ growing on the surface of Si nanoparticles (SiNPs) assisted by microwave irradiation. Of particular significance, the resultant materials, i.e., MOFs-encapsulated SiNPs (MOFs@SiNPs) could exhibit pH-responsive fluorescence, whose maximum emission wavelength is red-shifted from 442 to 592 nm when the pH increases from 2 to 13. More importantly, distinct room-temperature phosphorescence (maximum emission wavelength: 505 nm) could be observed in this system, with long lifetime of 215 ms. Taking advantages of above-mentioned unique optical properties, the MOFs@SiNPs are further employed as high-quality anti-counterfeiting inks for advanced encryption. In comparison to conventional fluorescence anti-counterfeiting techniques (static fluorescence outputs are generally used, thus being easily duplicated and leading to counterfeiting risk), pH-responsive fluorescence and room-temperature phosphorescence of the resultant MOFs@SiNPs-based ink could offer advanced multi-modal security, which is therefore capable of realizing higher-level information security against counterfeiting. UR - https://doi.org/10.1007/s12274-020-2781-1 DO - 10.1007/s12274-020-2781-1