MINIMIZING EXCITATION LIGHT LEAKAGE AND MAXIMIZING MEASUREMENT SENSITIVITY FOR MOLECULAR IMAGING WITH NEAR-INFRARED FLUORESCENCE

Near-infraredfluorescence(NIRF)imaging involves the separation of weakfluorescence signals from backscattered excitation light.The measurement sensitivity of current NIRF imaging systems is limited by the excitation light leakage through rejectionfilters.In this contribution,the authors demonstrate that the excitation light leakage can be suppressed upon using appropriatefilter combination and permutations.The excitation light leakage and measurement sensitivity were assessed and compared in this study by computing the transmission ratios of excitation to emission light collected and the signal-to-noise ratios in well-controlled phantom studies with differentfilter combinations and permutations.Using appropriatefilter combinations and permutations,we observe as much as two orders of magnitude reduction in the transmission ratio and higher signal-to-noise ratio.

Preparation of NaYF_4:Er^(3+)/TiO_2 composite and up-conversion luminescence properties under visible light excitation

The up-conversion luminescence composite NaYF4：Er3＋/TiO2 is prepared using the sol-gel method. The specimen has good crystallinity and two shapes, i.e., viereck and round, while the sizes of viereck and round particles are both micron-sized. The TiO2 has an anatase structure, while the NaYF4 has a hexagonal phase, which can be hardly obtained through the common sol-gel method. Due to the big particle size and the high crystallinity of pure NaYF4： Er3＋, the composite has a small specific surface area that is less than Degussa P25 TiO2. The NaYF4：Er3＋/TiO2 composite shows several emission peaks at 211, 237, and 251 nm under the excitation of 388 nm, at 395 nm and 411 nm under the excitation of 500 nm, and at 467, 481,492, and 508 nm under the excitation of 570 nm.

S vacancy modulated Zn_(x)Cd_(1-x)S/CoP quantum dots for efficient H_(2) evolution from water splitting under visible light

Energy band structure and interfacial compatibility of heterojunctions are crucial for photocatalysts in promoting photogene rated charge separation and transfer.Here,a combined strategy of vacancy engineering and quantum effect via a facile phosphating process is reported,for the first time,to modulate the energy band structure and the interface of Zn_(x)Cd_(1-x)S/CoP quantum dots(ZCS_(v)/CoP QDs)heterojunction.The combined experimental and theoretical investigation revealed that phosphating process transformed CoO_(x) QDs to CoP QDs,and more importantly,generated considerable amount of sulfur vacancies in ZCS_(v).As a result,a TypeⅡZCS_(v)/CoP QDs heterojunction with compatible interfaces was constructed via in-situ generated P-Zn,P-Cd and S-Co bonds,which facilitated the separation and transfer of the photogenerated charge and thus resulted in a high ability towards hydrogen evolution under visible light(17.53 mmol g^(-1) h^(-1)).This work provides an effective and adaptable strategy to modulate band structure and interfacial compatibility of heterojunctions via vacancy engineering and quantum effect.

Visible Light Excitable SCN^- Selective Fluorescence Probe Derived from Thiophene

An efficient fluorescence probe, 4-methyl-2,6-bis（（thiophen-2-ylmethylimino）methyl）phenol （DFPTMA） and its SCN adduct has been synthesized and characterized by different spectroscopic techniques like ^1H NMR,^13C NMR, QTOF-MS ES^＋, UV-Vis and FTIR spectroscopy. Single crystal X-ray structure of DFPTMA is reported. In presence of SCN-, DFPTMA exhibits significant fluorescence enhancement （λEx, 455 nm, λEm, 504 nm） in aqueous methanol （water-methanol, 1 ： 4, V/V, 0.1 mol/L HEPES buffer, pH 7.4）. Common bio-relevant anions viz. CH3COO^-, NO2, NO7, Cl^-, Br^-, I^-, SO4^2-, HSO4^-, N3^-, HAsO4^2-, Cr2O7^2-, H2PO4, ClO4^-, NCO^-, CN^-, CO3^2-, F^-, PO4^3-, S2-, HS- do not interfere in the recognition of SCN-. Lowest detection limit for SCN^- is 0.88 μmol/L with response time 〈5 min. The SCN assisted enhancement in emission intensity may be attributed to the formation of H-bond which enhances the rigidity of the molecular assembly.

Diversiform gas sensors based on two-dimensional nanomaterials

Two-dimensional(2D)nanomaterials have been widely used in gas sensing due to their large specific surface area,high surface reactivity,and excellent gas adsorption properties.This paper reviews the typical synthesis methods of various types of 2D nanomaterials and summarizes the recent progress in gas sensors based on 2D materials,such as noble metal nanoparticles(NPs),metal oxides(MOS),conductive polymers,other new 2D materials.The methods of doping,modification,and photoexcitation can effectively improve the gas-sensing properties of 2D materials.The sensitive mechanisms of heterojunction,Schottky junction,and photoexcitation in 2D material sensors are discussed in detail.This paper discusses the application prospects of 2D materials in wearable gas sensors,food safety,and self-powered sensing,and provides ideas for further applications in environmental quality monitoring and disease diagnosis.In addition,the opportunities and challenges for gas sensors based on 2D materials are also discussed.

High temperature thermo-photocatalysis driven carbon removal in direct biogas fueled solid oxide fuel cells

Solid oxide fuel cells(SOFCs)can directly convert renewable biogas into electricity with high efficiency at high temperature,however the long-term stability of SOFCs is significantly affected by the carbon deposition on the anode during cell operation.Herein,we report a novel carbon removal approach by high temperature infrared light driven photocatalytic oxidation.Upon the comparison of electrochemical performance of Ni-YSZ anode and TiO_(2)modified Ni-YSZ anode in the state-of-the-art single cell(Ni-YSZ/YSZ/LSCM),the modified anodes exhibit markedly improved peak powder density with simulated biogas fuel(70%CH_(4)+30%CO_(2))at 850℃with less coking after 40 h operation.The high activity and carbon deposition resistance of the modified anode is possibly attributed to the in situ generated hydroxyl radical from the reduced TiO_(x)powder under high temperature infrared light excitation,which is supported by detailed analysis of microstructural information of anodes and the powder-based thermo-photocatalytic experiments.