Formation of the Inclusion Complex of Orange Ⅱ with β-Cyclodextrin and Its Photostability

Inclusion complex of Orange II with β-Cyclodextrin (β-CD) and the anti-photolysis effect under UV-light were investigated. The molar ratio of inclusion complex of β-Cyclodextrin and Orange Ⅱ is 1∶1. The formation constant K=1.236×10 3 L/mol was determined by the UV and Fluorescence spectra respectively, which was quite in accordance with the calculation with a modified Benesi-Hildbrand equation. The inclusion complex was characterized by the IR spectra and the molar ratio of inclusion complex is 1∶1 too. The formation constant K=1.266×10 3 L/mol was determined by 1 H NMR analysis and was nearly the same by UV and fluorescence spectra. The photocatalytic decolorization rate of Orange Ⅱ solutions containing β-CD and TiO_ 2 was smaller by 51.9% than that of the Orange Ⅱ solutions only containing TiO_ 2 , while in the case of direct photolysis of Orange Ⅱ solutions, β-CD can lower the photolysis rate by 48.1% under UV-light. This result indicates β-CD can inhibit the photolysis and photocatalytic decolorization of Orange Ⅱ under UV-light. The β-CD inclusion complex was found to be persistent to UV-light photolysis.

Enhancing photostability and power conversion efficiency of organic solar cells by a “sunscreen” ternary strategy

The field has witnessed the rapid growth in the power conversion efficiency(PCE)of organic solar cells(OSCs)over the past decade,reaching the threshold for practical commercialization.However,a major issue remains that OSC lifetimes are seriously limited by the ultraviolet(UV)-induced photodegradation.Here,inspired by the superior photostability of car paint under sunlight and ambient air,a“sunscreen”molecule,2-(2-hydroxy-5-tert-octylphenyl)benzotriazole(UV329),is used to construct the PM6:Y6 ternary device.The addition of UV329 mainly enhances the ordered stacking of PM6 and increases the light utilization of blend films with the improved crystallization and appropriate phase separation.Accordingly,the ternary device exhibits stronger light response and obviously higher and more balanced carrier mobilities,contributing to higher short-circuit current density,fill factor and PCE.Similar PCE boost is also verified in PM6:BTP-e C9 and PM6:L8-BO systems.The photodegradation of PM6 dominates the photo-degradation process of PM6:Y6 systems,while the UV329 can effectively suppress such degradation,and thus the ternary device can retain nearly 90%of the initial PCE under continuous illumination for 120 min.Moreover,ternary devices also preserve better thermal stability and shelf-life with the enhanced PCE.This work provides a simple yet effective strategy for simultaneously improving PCE and photostability of OSCs.

Covalence bridge atomically precise metal nanocluster and metalorganic frameworks for enhanced photostability and photocatalysis

Metal nanoclusters(NCs)with precise structure and ultrasmall size have attracted great interests in catalysis.However,the poor stability has limited its large-scale use.Herein,we proposed the“covalence bridge”strategy to effectively connect atomically precise metal NCs and metal-organic frameworks.Benefiting from the covalent linkage,the synthesized UiO-66-NH2-Au25(LCys)18 showed outstanding stability after 16 h photocatalysis.Moreover,the covalence bridge created a strong metal-support interaction between the two components and provided an effective charge transport channel and thereby enhanced photocatalytic activity.UiO-66-NH2-Au25(L-Cys)18 displayed an exceptional photocatalytic H2 production rate,which is 21 and 90 times higher than that of UiO-66-NH2/Au25(PET)18(made by physically combination)and bare UiO-66-NH2,respectively.Thermodynamic and kinetic studies demonstrated that UiO-66-NH2-Au25(L-Cys)18 exhibited higher charge transfer efficiency,lower overpotential of water reduction and activation energy barrier compared with its counterparts.

Anaerobic environment as an efficient approach to improve the photostability of fatty acid photodecarboxylase

Fatty acid photodecarboxylase of Chlorella variabilis NC64A(CvFAP) is a novel photoenzyme with great potential in the treatment of waste lipids and production of sustainable aviation fuel. However, the fragile nature of Cv FAP to blue light is an urgent challenge. Herein, we demonstrated anaerobic environment could significantly improve the photostability of Cv FAP for the first time. The decarboxylation of palmitic acid by Cv FAP for 3 h under anaerobic environment increased pentadecane yield by 44.7% as compared to that under aerobic environment. The residual activity of Cv FAP after blue-light preillumination in the absence of palmitic acid for 0.5 h under anaerobic environment was 80.4%, which was 258.7 times higher than that under aerobic environment. Remarkable accumulation of superoxide radical and singlet oxygen in Cv FAP under aerobic environment led to the poor photostability of Cv FAP. Anaerobic environment helped to mitigate the production of superoxide radical and singlet oxygen in Cv FAP, improving the photostability of Cv FAP.

Enhancement strategies of targetability, response and photostability for in vivo bioimaging

Analyses of the physiology and pathology of active biochemical species in their native contexts are critical for early diagnosis and therapy. Optical imaging has emerged as one of the promising modalities for noninvasive and real-time visualization of important biomolecules or biological events, and it has witnessed major advances in the field of imaging in vitro and in vivo. In this review, we present a survey of common approaches and tactics for enhanced targetability, response rate, and photostability in bioimaging applications. Recently developed and representative examples are illustrated on the cellular and tissue levels.

Crosslink-enhanced strategy to achieve multicolor long-lived room temperature phosphorescent films with excellent photostability

Room temperature phosphorescence(RTP)films have recently attracted increasing attention due to their excellent luminescent properties for information encryption,optoelectronic devices,and sensors.However,polyvinyl alcohol(PVA)films with abundant hydrogen bonds to suppress triplet energy dissipation suffered from the humidity induced phosphorescence quenching under storage in the air for a long time.In this work,poly(acrylic acid)(PAA)was selected to crosslink PVA matrix through esterification reactions for preparing water resistant RTP films.The blue,cyan,and orange emissive RTP films were successfully obtained by incorporating three different organic compounds into PVA-PAA crosslinking films.Crosslinking strategy significantly improved the phosphorescence emissions of the doped films,and effectively blocked the absorption of water molecular,leading to the excellent photostability of the developed films.As a proof of concept,the white light phosphorescence film and anti-counterfeiting applications were successfully demonstrated.

A feasible method for comparing the power dependent photostability of fluorescent proteins

A feasible method of combining the concept of fluorescence half-life and the power dependent photo- bleaching rate for characterizing the practical photostability of fluorescent proteins （FPs） was introduced. Furthermore, by using a fluorescent photostability standard, a relative comparison of the photostabilty of FPs from different research groups was proposed, which would be of great benefit for developing novel FPs with optimized emission wavelength, better brightness, and improved photostability. We used rho- damine B as an example to verify this method and evaluate the practical photostability of a far-red FP, mKate-S158C. Experimental results indicated good potential of this method for further study.

Highly efficient organic solar cells with improved stability enabled by ternary copolymers with antioxidant side chains

The stability of organic solar cells(OSCs)remains a major concern for their ultimate industrialization due to the photo,oxygen,and water susceptibility of organic photoactive materials.Usually,antioxidant additives are blended as radical scavengers into the active layer.However,it will induce the intrinsic morphology instability and adversely affect the efficiency and long-term stability.Herein,the antioxidant dibutylhydroxytoluene(BHT)group has been covalently linked onto the side chain of benzothiadiazole(BT)unit,and a series of ternary copolymers D18-Cl-BTBHTx(x=0,0.05,0.1,0.2)with varied ratio of BHT-containing side chains have been synthesized.It was found that the introduction of BHT side chains would have a negligible effect on the photophysical properties and electronic levels,and the D18-Cl-BTBHT0.05:Y6-based OSC achieved the highest power conversion efficiency(PCE)of 17.6%,which is higher than those based active layer blended with BHT additives.More importantly,the unencapsulated device based on D18-Cl-BTBHTx(x=0.05,0.1,0.2)retained approximately 50%of the initial PCE over 30 hours operation under ambient conditions,significantly outperforming the control device based on D18-Cl(90%degradation in PCE after 30 h).This work provides a new structural design strategy of copolymers for OSCs with simultaneously improved efficiency and stability.

HSA shrinkage optimizes the photostability of embedded dyes fundamentally to amplify their efficiency as photothermal materials

Focused on the performance promotion of organic small molecular dyes based photothermal agents via non-chemical modification,we found that heat-assisted binding of human serum albumin(HSA)to the dye causes shrinkage of the protein and encapsulate the dye to form nanoparticles.This revolutionizes the photostability of small molecule dyes which further improves their photothermal conversion effi-ciency and tumor ablation performance as photothermal agents significantly.In this work,the obtained photothermal agent named HSA-P2-T could accumulate in tumor and induce 22℃enhancement of the tumor in xenograft models upon ultra-low dose(0.1 W/cm^(2))laser irradiation,which,as far as we know,is the lowest laser dose used in vivo photothermal therapy.Utilizing HSA-P2-T,we realized tumor ablation upon twice intravenous injections of the nanoparticles and four photothermal treatments.

Fabrication of Semiconductor Polymer Membranes Combined with a Colored Charge Transfer Complexes Used in the Manufacture of Solar Cells as a Source of Alternative Energy

The main task of this article was to prepared of new pigment model in situ solar cells accordance to charge-transfer complexes of rhodamine C(RhC) donor as dye laser gain media with iodine(σ-acceptor) and chloranilic acid, CLA(π-acceptor). The synthesis stoichiometry of these complexes were of 1∶2(donor∶acceptor) with general formulas [(RhC)]I·I3 and [(RhC)(CLA)2]. The discussed data of elemental analysis, conductivity measurements, FT-IR, UV-Vis spectroscopy and photometric titration data visualized the stoichiometry, formula and complexity of the complexes. The physicochemical and spectroscopic analyses obtained suggested that the electron transfer occurred through nitrogen atom in a tertiary amine —N(C2H5)2 of RhC donor with acceptor. The synthesized solid complexes were under go to thermogravimetric analyses to investigate their thermal stability and decomposition steps. The molar conductance measurements revealed that RhC complexes have an electrolytic statement. The thermal stability of rhodamine C complexes was enhanced in comparable with RhC itself. The polymer membranes of poly-methyl methacrylate)(PMMA) combined with the RhC charge(transfer complexes in chloroform solvent have been prepared and characterized by(infrared & electronic) spectroscopy and scanning electron microscopy(SEM) morphological examination. The photo-stability properties of the RhC complexes have been investigated.

RECENT RESEARCH AND DEVELOPMENT OF POLYMER OPTICAL FIBRES

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Liquisolid technique and its applications in pharmaceutics

Most of the newly developed drug candidates are lipophilic and poorly water-soluble. Enhancing the dissolution and bioavailability of these drugs is a major challenge for the pharmaceutical industry. Liquisolid technique, which is based on the conversion of the drug in liquid state into an apparently dry, non-adherent, free flowing and compressible powder,is a novel and advanced approach to tackle the issue. The objective of this article is to present an overview of liquisolid technique and summarize the progress of its applications in pharmaceutics. Low cost, simple processing and great potentials in industrial production are main advantages of this approach. In addition to the enhancement of dissolution rate of poorly water-soluble drugs, this technique is also a fairly new technique to effectively retard drug release. Furthermore, liquisolid technique has been investigated as a tool to minimize the effect of pH variation on drug release and as a promising alternative to conventional coating for the improvement of drug photostability in solid dosage forms. Overall, liquisolid technique is a newly developed and promising tool for enhancing drug dissolution and sustaining drug release, and its potential applications in pharmaceutics are still being broadened.

Synthesis and characterization of new fluorescent nanoparticles

A novel kind of fluorescent nanoparticles（FNPs）has been prepared using a precipitation polymerization method.Methacrylic acid,trimethylolpropane trimethacrylate and azobisisobutyronitrile were used as functional-monomer,cross-linker and initiator, respectively.Compared with other fluorescent nanoparticles,the FNPs have the characteristics including low dye leakage and good photostability.The fluorescence microscopy imaging indicates that the FNPs can be used as fluorescent labels in bioanalysis.

PM567-Doped solid dye lasers based on PMMA

Polymers are a kind of attractive hosts for laser dyes due to their high transparency in both pumping and lasing ranges and superior optical homogeneity. In this paper solid dye samples based on polymethyl methacrylate （PMMA） doped with different concentrations of 1, 3, 5, 7, 8 -pentamethyl-2, 6-diethylpyrromethene-BF2 （PM567） are prepared. The absorption, fluorescence and lasing spectra of the samples are obtained. Wide absorption and fluorescence bands are obtained and a red shift of the maxima of the lasing emission spectra is observed. With the second-harmonic generation of Q-switched Nd：YAC laser （532 nm, -20 ns） pumping the samples longitudinally, the slope efficiencies of the samples are obtained. There is an optimal dye concentration for the highest slope efficiency when the pumping energy is lower than some typical value （-250 mJ）, and the highest slope efficiency 35.6% is obtained in the sample with a dye concentration of 2 × 10^-4 mol/L. Pumping the samples at a rate of 10Hz with a pulse energy as high as 200 mJ （the fluence is 0.2 J/cm^2）, the output energy drops to one-half of its initial value after approximate 15500 pulses and the normalized photostability is 5.17CJ/mol. A kind of solid dye laser which could have some applications is built.

Immunofluorescent Labeling of Human HepG2 Cells with CdTe Quantum Dot Probe Conjugated with Anti-pan CK MAb

A relatively sensitive, specific, and photostable method for the detection of cytokeratin of cancer cells via conjugation with cadmium telluride quantum dots（CdTe QDs） was described. Water soluble CdTe QDs were conjugated to anti-pan-cytokeratin（CK） monoclonal antibody（MAb） through coupling reagent [1-ethyl-3-（3-dimethyla- mino propyl）carbodiimide, EDC] and the conjugates were purified by dialysis. The expression of pan CK protein in HepG2 cells was observed by immunocytochemistry and direct immunofluorescence via QDs-Ab conjugates respectively. Fluorescence intensity and photostability of QDs were compared with those of FITC（fluorescein isothiocyanate）. The results show that the QDs-Ab conjugates recognized specifically pan CK protein in HepG2 cells. Compared with FITC, CdTe QDs had higher brightness and photostability without obvious photobleaching under continuous exciting light illumination for 30 min and after the placement at room temperature for 3 d. The results indicate that conjugates of CdTe quantum dot with anti-pan CK MAb can be used for labeling cancer cells derived from epithelial tissues, which provides the basis for the detection of circulating tumor cells（CTCs）.

Optical, Photophysical, Stability and Mirrorless Lasing Properties of Novel Fluorescein Derivative Dye in Solution

Novel laser dye, allyl 2-(6-(allyloxy)-3-oxo-3H-xanthen-9-yl) benzoate [diallyl-fluorescein] has been synthesized. Its chemical structure was confirmed by 1HNMR, IR, MS and elemental analysis. Its optical properties were experimentally investigated. The amplified spontaneous emission (ASE) efficiency was 0.29% in case of new dye while it was 0.23% in case of fluorescein by pumping the dye samples with a 532 nm (7 ns) pulsed Nd:YAG laser. Also, the thermal and photostability techniques confirmed the higher stability of new laser dye.

Preparation and Characterization of Nanostructured Lipid Carrier Loaded with UVA/UVB Filters

A new photoprotective system based on encapsulating UVA (butyl methoxydibenzoylmethane, BMBM) and UVB (octyl methoxycinnamate, OMC) filters into nanostructured lipid carriers (NLC) has been prepared to develop cosmetic formulations with effective UV protection. BMBM/OMC-loaded NLC was prepared by ultrasonication-homogenisation, and analysed by particle size, zeta potential (ZP), encapsulation efficiency (EE), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Moreover, the UV protection property and photostability were investigated and compared with BMBM/OMC-conventional emulsions. The particle size and ZP of BMBM/OMC-loaded NLC were 310.24 nm and -33.6 mV, EE of BMBM and OMC were 85.46% and 99.32%. SEM, FTIR and DSC analysis confirmed BMBM and OMC entrapped in the lipid matrix core and the structure was stable during storage. Compared with conventional emulsion, BMBM/OMC-loaded NLC displayed perfect photo protection property in whole UV range. The photostability studies showed that the NLC can improve the photostability of sunscreens.

Highly efficient and non-doped red conjugated polymer dot for photostable cell imaging

By introducing a naphthothiadiazole(NT)unit as the main building block,a non-doped and red emissive conjugated polymer poly(9,9-dihexylfluorene-alt-naphthothiadiazole)(PFNT)is readily obtained through a two-step synthesis.Since the NT unit has a large twist angle with its neighboring segment,the aggregation-induced quenching(AIQ)effect of PFNT can be effectively suppressed in the condensed state.As a result,the corresponding PFNT polymer dot(Pdot)exhibits a high fluorescence quantum yield of53.2%with peak emission at 616 nm,which is one of the most efficient red Pdots known.PFNT Pdot shows good biocompatibility and can be employed for living cell fluorescent imaging with high brightness.It also can be used for specific subcellular organelle imaging through immunofluorescence labeling.Furthermore,the PFNT Pdot demonstrates much better photostability for long-time cell fluorescence imaging than commercial red dyes.The high performances of PFNT Pdot make it a promising fluorescent probe for practical bioapplications.

高稳定性铋基钙钛矿纳米晶的可控合成:结构和光物理性质

铋基钙钛矿因毒性低成为铅基钙钛矿的潜在替代品.目前,对铋基钙钛矿纳米晶的化学组成、晶体结构以及光物理过程的研究还缺乏系统性.特别地,紫外-可见吸收光谱和激发态载流子动力学,在已发表的论文中存在相当大的争议.在本文中,我们通过热注入法成功地合成了纯相的Cs_(3)BiBr_(6)和Cs_(3)Bi_(2)Br_(9)纳米晶,并通过调节热注入的温度来精确控制二者的化学组成和结构.在此基础上,系统研究了不同形貌和不同尺寸的Cs_(3)Bi_(2)Br_(9)纳米晶的紫外-可见吸收光谱,澄清了在这方面存在的争议.采用飞秒瞬态吸收光谱系统研究了Cs_(3)Bi_(2)Br_(9)纳米晶的激发态载流子动力学,结果表明载流子在被激发后的3 ps内会发生一个自捕获过程.与配体辅助再沉积法相比,用热注入法制备的Cs_(3)Bi_(2)Br_(9)纳米晶具有更好的光稳定性.基于Cs_(3)Bi_(2)Br_(9)纳米晶的光电探测器具有灵敏的光响应,显示出其在光电探测方面的应用潜力.