Anchoring Carbon Nanodots onto Nanosilica for Phosphorescence Enhancement and Delayed Fluorescence Nascence in Solid and Liquid States.

Carbon nanodots (CDs) anchored onto inorganic supporter (amorphous nanosilica, SiO2 ) like a core-satellite structure have enhanced the room-temperature phosphorescence (RTP) intensity along with ultralong lifetime of 1.76 s. Special and quite stable structure should account for these superiorities, including hydrogen network, covalent bond, and trap-stabilized triplet-state excitons that are responsible for the generation of phosphorescence. These multiple effects have efficaciously protected CDs from being restrained by the external environment, providing such long-lived emission (LLE) that can subsist not only in powdery CDs-SiO2 but also coexist in aqueous solution, pushing a big step forward in the application prospects of liquid-state phosphorescence. Through construction of CDs-SiO2 compound, electron trap is reasoned between CDs and SiO2 by analyzing thermoluminescent glow curve. Electron trap can capture, store, and gradually release the electrons just like an electron transporter to improve the intersystem crossing (ISC) and reserved ISC, having provided the more stabilized triplet excitons, stronger and longer phosphorescence, and also triggered the formation of thermally activated delayed fluorescence (TADF), offering a new mechanism for exploiting LLE among CD-based field. Moreover, it is more beneficial to the formation of TADF as temperature increases, thus the afterglow color can change with the temperature.

Solid-State Carbon Dots with Red Fluorescence and Efficient Construction of Dual-Fluorescence Morphologies.

Stable solid-state red fluorescence from organosilane-functionalized carbon dots (CDs) with sizes around 3 nm is reported for the first time. Meanwhile, a novel method is also first reported for the efficient construction of dual-fluorescence morphologies. The quantum yield of these solid-state CDs and their aqueous solution is 9.60 and 50.7%, respectively. The fluorescence lifetime is 4.82 ns for solid-state CDs, and 15.57 ns for their aqueous solution. These CDs are detailedly studied how they can exhibit obvious photoluminescence overcoming the self-quenching in solid state. Luminescent materials are constructed with dual fluorescence based on as-prepared single emissive CDs (red emission) and nonfluorescence media (starch, Al2 O3 , and RnOCH3 COONa), with the characteristic peaks located at nearly 440 and 600 nm. Tunable photoluminescence can be successfully achieved by tuning the mass ratio of CDs to solid matrix (such as starch). These constructed dual-fluorescence CDs/starch composites can also be applied in white light-emitting diodes with UV chips (395 nm), and oxygen sensing.

Mesoporous Silica-Encapsulated Gold Nanorods for Drug Delivery/Release and Two-Photon Excitation Fluorescence Imaging to Guide Synergistic Phototherapy and Chemotherapy.

Photothermal therapy is a promising light-based medical treatment that relies on light absorption agents converting light irradiation into localized heat to destroy cancer cells or other diseased tissues. It is critical to enhance the therapeutic effects of cancer cell ablation for their practical applications. This study reports a high-performance combinational therapy for ablating cancer cells, including both photothermal therapy and chemotherapy to improve therapeutic efficiency. The prepared AuNR@mSiO2 loading molecular Doxorubicin (Dox) assemblies were highlighted by merits of facile acquisition, great stability, easy endocytosis, and rapid drug release in addition to improved anticancer capability upon irradiation with a femtosecond pulsed near-infrared (NIR) laser, where AuNR@mSiO2 nanoparticles afforded a high photothermal conversion efficiency of 31.7%. Two-photon excitation fluorescence imaging was introduced into confocal laser scanning microscope multichannel imaging to track the drug location and cell position in real time for monitoring the process of drug delivery in killing human cervical cancer HeLa cells and then to realize imaging-guiding cancer treatment. These nanoparticles exhibit widespread potential in photoresponsive utilizations including photothermal therapy, chemotherapy, one- and two-photon excited fluorescence imaging, and 3D fluorescence imaging and cancer treatment.

Bioinspired Supramolecular Nanotoroids with Aggregation-Induced Emission Characteristics.

Supramolecular toroids have attracted continuous attention because of their fascinating topological structure and important role in biological systems. However, it still remains a great challenge to construct supramolecular functional toroids and clarify the formation mechanism. Herein, we develop a strategy to prepare supramolecular helical fluorescent nanotoroids by cooperative self-assembly of an amino acid and a dendritic amphiphile (AIE-den-1) with aggregation-induced emission characteristics. Mechanistic investigation on the basis of fluorescence and circular dichroism analyses suggests that the toroid formation can be driven by the interactions of AIE-den-1 with amino acid and goes through a topological morphology transformation from nanofibers to left-handed nanotoroids by means of a twist-fused-loop process.

Luminescent properties and energy transfer of luminescent carbon dots assembled mesoporous Al(2)O(3): Eu(3) co-doped materials for temperature sensing.

Owning to the hydrogen-band interactions, blue-light-emitting luminescent carbon dots (CDs) synthesized by one-pot hydrothermal treatment were successfully assembled into Eu3+ doped mesoporous aluminas (MAs). Interesting, dual-emissive CDs/MAs co-doped materials with higher quantum yield (QY), long-term stability, mesoporous structure, high thermal stability, and large surface areas were obtained. Furthermore, the obtained CDs/MAs co-doped materials possessed tunable color, and excellent temperature sensitivity due to the existing of energy transfer between CDs and Eu3+ ion. The energy transfer efficiency (η) and energy transfer probability (P) for CDs/Eu3+ co-doped materials possessed a monotonous tendency with the change of Eu3+ content. More importantly, the dual-emissive colors can be regularly adjusted through regulating their excitation wavelength or relative mass ratio. In addition, the emission intensity of the CDs/MAs co-doped materials gradually decreased with increasing temperature showing the clear temperature dependence, this dual-emissive thermometer was with high sensitivity, owning a great fitted curve in the range from 100 to 360K under a single wavelength excitation.