The continuously growing importance of information storage, transmission, and authentication impose many new demands and challenges for modern nano-photonic materials and information storage technologies, both in security and storage capacity. Recently, luminescent lanthanide-doped nanomaterials have drawn much attention in this field because of their photostability, multimodal/multicolor/narrowband emissions, and long luminescence lifetime. Here, we report a multimodal nanocomposite composed of lanthanide-doped upconverting nanoparticle and EuSe semiconductor, which was constructed by utilizing a cation exchange strategy. The nanocomposite can emit blue and white light under 365 and 394 nm excitation, respectively. Meanwhile, the nanocomposites show different colors under 980 nm laser excitation when the content of Tb3+ ions is changed in the upconversion nanoparticles. Moreover, the time-gating technology is used to filter the upconversion emission of a long lifetime from Tb3+ or Eu3+, and the possibilities for modulating the emission color of the nanocomposites are further expanded. Based on the advantage of multiple tunable luminescence, the nanocomposites are designed as optical modules to load optical information. This work enables multi-dimensional storage of information and provides new insights into the design and fabrication of next-generation storage materials.
Modulating the emission wavelengths of materials has always been a primary focus of fluorescence technology. Nanocrystals (NCs) doped with lanthanide ions with rich energy levels can produce a variety of emissions at different excitation wavelengths. However, the control of multimodal emissions of these ions has remained a challenge. Herein, we present a new composition of Er3+‐based lanthanide NCs with color‐switchable output under irradiation with 980, 808, or 1535 nm light for information security. The variation of excitation wavelengths changes the intensity ratio of visible (Vis)/near‐infrared (NIR‐II) emissions. Taking advantage of the Vis/NIR‐II multimodal emissions of NCs and deep learning, we successfully demonstrated the storage and decoding of visible light information in pork tissue.
Fluorescence bioimaging has always been a research hotspot in the field of life sciences and medicine. Although many studies focus on the promising second near infrared window (NIR-II) imaging, the NIR-II imaging with deep tissue penetration is limited by the broad emission band widths. Herein, a well-designed lanthanide doped nanocrystal is presented that can modulate the energy migration processes by controlling energy migration pathway and cerium-assisted energy transfer processes, resulting in switchable emission modes of visible and NIR-II that dependent by the excitation wavelengths. Subsequently, the multimode emissions of dumbbell-like nanocrystals are cooperated with deep learning, where the advantages of narrow emission peak of visible fluorescence and deep tissue penetration of NIR-II fluorescence are combined to offer a unique deep learning fluorescence bioimaging. By this new imaging method, fluorescence signals can be obtained with narrow emission peak and high signal-to-noise ratio after penetrating phantom tissue. This study brings a powerful idea for cutting-edge applications of intelligent optical materials, such as in vivo information security.
Information encoding security has always been a research hotspot in the optical field. Although many studies focused on luminescent materials and techniques for information security, the optical information encoding is limited by low information capacity and security. Herein, we present new core‐shell‐shell (CSS) lanthanide‐doped nanocrystals which display multi‐stimuli‐responsive and multimode emission. In the designed CSS nanostructure, the Stokes and anti‐Stokes processes can be both achieved in the same nanocrystals under the excitation of 1532, 980, and 254 nm via self‐excited Er3+ and Ce3+‐sensitized mechanisms. Subsequently, a group of unique multimode emission CSS nanocrystals were designed as optical modules and successfully utilized in multidimensional information encoding, which demonstrates high‐level information encoding capability and security. This work brings a powerful idea for information encoding security designs based on multimode luminesce materials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.