Novel Multifunctional NIR-II Aggregation-Induced Emission Nanoparticles Assisted Intraoperative Identification and Elimination of Residual Tumor

Incomplete tumor resection is the direct cause of the tumor recurrence and metastasis after surgery. Intraoperative accurate detection and elimination of microscopic residual cancer improve surgery outcomes. In this study, a powerful D1-π-A-D2-R type phototheranostic based on aggregation-induced emission (AIE)-active the second near-infrared window (NIR-II) fluorophore is designed and constructed. The prepared theranostic agent, A1 nanoparticles (NPs), simultaneously shows high absolute quantum yield (1.23%), excellent photothermal conversion efficiency (55.3%), high molar absorption coefficient and moderate singlet oxygen generation performance. In vivo experiments indicate that NIR-II fluorescence imaging of A1 NPs precisely detect microscopic residual tumor (2 mm in diameter) in the tumor bed and metastatic lymph nodes. More notably, a novel integrated strategy that achieves complete tumor eradication (no local recurrence and metastasis after surgery) is proposed. In summary, A1 NPs possess superior imaging and treatment performance, and can detect and eliminate residual tumor lesions intraoperatively. This work provides a promising technique for future clinical applications achieving improved surgical outcomes.

Highly emissive MAPbBr3 perovskite QDs by ligand-assisted reprecipitation: the antisolvent effect

A systematic study of the synthetic procedure to improve quantum efficiency of luminescent hybrid perovskite QDs through ligand-assisted precipitation method is presented. Particularly, the influence of the dielectric constant and dipole moment of the antisolvent on the reaction time and the photophysical properties of the QDs is highlighted. After evaluating the influence of antisolvents and optimizing experimental parameters such as reaction time and Pb excess of the precursor, colloidal crystalline MAPbBr3 QDs with exceptionally high absolute quantum yield up to 97.7% in solution and 69.1% in solid film were obtained. Finally, MAPbBr3 QDs precipitated from anisole were processed like UV-curable nanocomposite as efficient down conversion layer resulting in very narrow green emission LED.

Influence of Chitosan-Based Carbon Dots on Astaxanthin Production of Green Alga Tetraselmis sp.

CDs are carbon fluorescent nanomaterials that have gained significant attention in recent years owing to their unique properties. In this work, we utilized a simple solution to produce CDs with func-tionalized amino groups via a one-step carbonization from a chitosan precursor. This simultaneous approach does not use special reagent for either the formation step or the amino-functionalization step of CDs. The as-prepared amino-functionalized CDs that possesses expected characteristics, such as nano-size distribution, monodispersible, high blue light emission, high absolute quantum yield of 5.52%, and functionalized amino groups on the surface. Furthermore, this work demonstrated the low cytotoxicity and high biocompatibility of the CDs, through the improvements in the astaxanthin production of alga Tetraselmis sp. (more than doubled (up to 0.044 mg/L), relative to the control). Thus, as-prepared CDs have promising properties not only for applications in bioimaging, drug delivery or sensors, but also as promoter in algal biorefinery

Absolute quantum yield measurements of fluorescent proteins using a plasmonic nanocavity

One of the key photophysical properties of fluorescent proteins that is most difficult to measure is the quantum yield. It describes how efficiently a fluorophore converts absorbed light into fluorescence. Its measurement using conventional methods become particularly problematic when it is unknown how many of the proposedly fluorescent molecules of a sample are indeed fluorescent (for example due to incomplete maturation, or the presence of photophysical dark states). Here, we use a plasmonic nanocavity-based method to measure absolute quantum yield values of commonly used fluorescent proteins. The method is calibration-free, does not require knowledge about maturation or potential dark states, and works on minute amounts of sample. The insensitivity of the nanocavity-based method to the presence of non-luminescent species allowed us to measure precisely the quantum yield of photo-switchable proteins in their on-state and to analyze the origin of the residual fluorescence of protein ensembles switched to the dark state.

Pb(Er1/2Nb1/2)O3–Pb(Zn1/3Nb2/3)O3–PbTiO3 Single Crystals with High Curie Temperature

In this work, 0.15Pb(Er1/2Nb1/2)O3–0.63Pb(Zn1/3Nb2/3)O3–0.22PbTiO3 (15PEN–63PZN–22PT) single crystals with a pure perovskite structure are obtained through the flux method. The phase structure, dielectric, ferroelectric properties and upconversion photoluminescence of the crystals are studied. The ternary crystals along the [110] orientation have a high Curie temperature (Tc = 250 °C) and large coercive field (Ec = 11.0597 kV/cm) which are higher than those of crystals reported previously. Furthermore, the PEN–PZN–PT crystals are produced with a strong green light excited by a 980 nm laser. Being in the range 298–478 K, the emission intensity of all peaks decreases with increase in temperature. The absolute quantum yield (QY) for the crystals is 0.00059%. These excellent properties provide new possibilities for multifunctional materials of optoelectronic devices.

Manifestation of Сoncentration Quenching of Fluoroaluminate Glasses Doped with Erbium

Fluoroaluminate glasses of the composition 2Ва (РО3)2–98MgCaSrBaYAl2F14-xErF3, where x=0, 0.1, 0.5, 1.0 mol. % have been prepared by melt quenching technique and characterized by optical absorption, emission spectra and decay curve analysis. Measured transmission spectra indicate the high practical relevance of the composition of glasses under investigation for photonics and optoelectronics products. In the region of 500–700 nm, luminescence spectra with peaks at about 522, 550, and 665 nm were obtained. The positions of the luminescence bands have been described using an erbium ion energy scheme. The concentration dependences of the absolute quantum yield values for the series of Er3+-doped fluoroaluminate glasses were also established. The maximum value of absolute quantum yield was found for a sample with Er3+ concentration 0.21∙1020 сm-3. The main reason for reducing the values of absolute quantum yield is concentration quenching.

Effects of Substituents on the Blue Luminescence of Disilane-Linked Donor‒Acceptor‒Donor Triads

A series of disilane-linked donor‒acceptor‒donor triads (D‒Si‒Si‒A‒Si‒Si‒D) was synthesized to investigate the effects of substituents on the photophysical properties. The triads were prepared by metal-catalyzed diiodosilylation of aryl iodides using a Pd(P(t-Bu)3)2/(i-Pr)2EtN/toluene system that we previously developed. Optical measurements, X-ray diffraction analysis, and density functional theory calculations revealed relationships between the photophysical properties and molecular structures of these triads in solution and in the solid state. The compounds emitted blue to green fluorescence in CH2Cl2 solution and in the solid state. Notably, compound 2 showed fluorescence with an absolute quantum yield of 0.17 in the solid state but showed no fluorescence in CH2Cl2. Our findings confirmed that the substituent adjacent to the disilane moiety affects the conformations and emission efficiencies of compounds in solution and in the solid state.