Near infrared emissions from both high efficient quantum cutting (173%) and nearly-pure-color upconversion in NaY(WO_(4))_(2):Er^(3+)/Yb^(3+) with thermal management capability for silicon-based solar cells

Raising photoelectric conversion efficiency and enhancing heat management are two critical concerns for siliconbased solar cells.In this work,efficient Yb^(3+) infrared emissions from both quantum cutting and upconversion were demonstrated by adjusting Er^(3+) and Yb^(3+) concentrations,and thermo-manage-applicable temperature sensing based on the luminescence intensity ratio of two super-low thermal quenching levels was discovered in an Er^(3+)/Yb^(3+) codoped tungstate system.The quantum cutting mechanism was clearly decrypted as a two-step energy transfer process from Er^(3+) to Yb^(3+).The two-step energy transfer efficiencies,the radiative and nonradiative transition rates of all interested 4 f levels of Er^(3+) in NaY(WO_(4))_(2) were confirmed in the framework of Föster-Dexter theory,Judd-Ofelt theory,and energy gap law,and based on these obtained efficiencies and rates the quantum cutting efficiency was furthermore determined to be as high as 173%in NaY(WO_(4))_(2):5 mol%Er^(3+)/50 mol%Yb^(3+) sample.Strong and nearly pure infrared upconversion emission of Yb3+under 1550 nm excitation was achieved in Er^(3+)/Yb^(3+)co-doped NaY(WO_(4))_(2) by adjusting Yb^(3+) doping concentrations.The Yb^(3+) induced infrared upconversion emission enhancement was attributed to the efficient energy transfer ^(4)I_(11/2)(Er^(3+))+^(2)F_(7/2)(Yb^(3+))→^(4)I_(15/2)(Er^(3+))+^(2)F_(5/2)(Yb^(3+))and large nonradiative relaxation rate of ^(4)I_(9/2).Analysis on the temperature sensing indicated that the NaY(WO_(4))_(2):Er^(3+)/Yb^(3+)serves well the solar cells as thermos-managing material.Moreover,it was confirmed that the fluorescence thermal quenching of ^(2)H_(11/2)/^(4)S_(3/2) was caused by the nonradiative relaxation of ^(4)S_(3/2).All the obtained results suggest that NaY(WO_(4))_(2):Er^(3+)/Yb^(3+) is an excellent material for silicon-based solar cells to improve photoelectric conversion efficiency and thermal management.

A novel strategy for improving upconversion luminescence of NaYF4：Yb, Er nanocrystals by coupling with hybrids of silver plasmon nanostructures and poly（methyl methacrylate） photonic crystals

与高贵金属的表面 plasmonic 回声(SPR ) 联合 upconversion nanophosphors (UCNP ) 是改进 UCNP 的光效率的一个有希望的方法；然而，完成稳定、可再现、有效的 upconversion 仍然是挑战通过如此的联合的光(UCL ) 改进。在这个工作，我们在场改进 NaYF4 的 UCL 的新奇策略:Yb3+ ， Er3+ UCNP，由联合银并且远地的联合的 SPR 的近地的联合 poly (甲基 methacrylate )(PMMA ) 有 UCNP 的蛋白石 photonic 晶体(OPC ) 。以便控制在 UCNP 和 SPR 之间的有效相互作用距离，由随机分布式的银 nanoparticles ( NP )组成的一部多孔的银电影(> 100 nm )被准备它在一个宽广波长范围上表明了强壮的 SPR ，并且它联合到 UCNP 被发现比一部稠密的电影的强壮得多。在 OPC 的远地的联合， PMMA OPC 的 photonic 站乐队(PSB ) 被调节到 980 nm，确切匹配刺激光。由 modulating， UCNP 的粒子尺寸，和这个事件的方向和刺激力量点亮， 60 褶层的最大的改进被观察，它是为导致金属的 UCL 改进系统的重要进展。

New molecular method to detect denitrifying anaerobic methane oxidation bacteria from different environmental niches

The denitrifying anaerobic methane oxidation is an ecologically important process for reducing the potential methane emission into the atmosphere.The responsible bacterium for this process was Candidatus Methylomirabilis oxyfera belonging to the bacterial phylum of NC10.In this study,a new pair of primers targeting all the five groups of NC10 bacteria was designed to amplify NC10 bacteria from different environmental niches.The results showed that the group A was the dominant NC10 phylum bacteria from the sludges and food waste digestate while in paddy soil samples,group A and group B had nearly the same proportion.Our results also indicated that NC10 bacteria could exist in a high p H environment(pH 9.24)from the food waste treatment facility.The Pearson relationship analysis showed that the p H had a significant positive relationship with the NC10 bacterial diversity(p<0.05).The redundancy analysis further revealed that the p H,volatile solid and nitrite nitrogen were the most important factors in shaping the NC10 bacterial structure(p=0.01)based on the variation inflation factors selection and Monte Carlo test(999 times).Results of this study extended the existing molecular tools for studying the NC10 bacterial community structures and provided new information on the ecological distributions of NC10 bacteria.

Up-conversion fluorescence biosensor for sensitive detection of CA-125 tumor markers

Sensitive and specific bioassays of tumor markers are critical for early cancer detection and treatment.In recent years,lanthanide(Ln3+)doped upconversion nanoparticles(UCNPs)have attracted wide attentions in tumor markers detectio n.Herein,we co mbined NaYF4:Yb,Tm and silver nanoparticles,serving as energy donor and receptor,respectively,to form an up-conversion fluorescence based inhibitory tumor marker biosensor system.The tumor marker CA-125 molecules are labeled with silver NPs,and the energy transfer fluorescent signal can be detected between the UCNPs and the silver NP receptors.The biosensor shows good stability,high sensitivity and selectivity in the tumor marker concentration range from 5 to 100 ng/mL,as well as a detection limit of 120 pg/mL.Due to the advantage of ease of fabrication and operation,low cost and high information capacity,this technology holds great potential for the clinical applications.

Fungal diversity and its mechanism of community shaping in the milieu of sanitary landfill

Land filling is the main method to dispose municipal solid waste in China.During the decomposition of organic waste in landfills,fungi play an important role in organic carbon degradation and nitrogen cycling.However,fungal composition and potential functions in landfill have not yet been characterized.In this study,refuse and leachate samples with different areas and depths were taken from a large sanitary landfill in Beijing to identify fungal communities in landfills.In high-throughput sequencing of ITS region,474 operational taxonomic units(OTUs)were obtained from landfill samples with a cutoff level of 3%and a sequencing depth of 19962.The results indicates that Ascomycota,with the average relative abundance of 84.9%,was the predominant phylum in landfill fungal communities.At the genus level,Family Hypocreaceae unclassified(15.7%),Fusarium(9.9%)and Aspergillus(8.3%)were the most abundant fungi found in the landfill and most of them are of saprotrophic lifestyle,which plays a big role in nutrient cycling in ecosystem.Fungi existed both in landfilled refuse and leachate while both the richness and evenness of fungal communities were higher in the former.In addition,fungal communities in landfilled refuse presented geographic variances,which could be partly attributed to physical habitat properties(pH,dissolved organic carbon,volatile solid,NH_(4)^(+),NO_(2)^(−)and NO_(3)^(−)),while NO_(3)^(−)was considered the most significant factor(p<0.05)in shaping fungal community.

Effects of Bi^(3+) on down-/up-conversion luminescence,temperature sensing and optical transition properties of Bi^(3+)/Er^(3+)co-doped YNbO_(4) phosphors

A series of YNbO_(4):Bi^(3+) and YNbO_(4):Bi^(3+)/Er^(3+) phosphors were prepared by a conventional high temperature solid-state reaction method.The results of XRD and Rietveld refinement confirm that monoclinic phase YNbO_(4)samples are achieved.The down-/up-conversion luminescence of Er^(3+) ions was investigated under the excitation of ultraviolet light(327 nm)and near infrared light(980 nm).Under 327 nm excitation,broad visible emission band from Bi^(3+) ions and characteristic green emission peaks from Er^(3+) ions are simultaneously observed,while only strong green emissions from Er^(3+) ions are detected upon excitation of 980 nm.Remarkable emission enhancement is observed in down-/up-conversion luminescence processes by introducing Bi^(3+) ions into Er^(3+)-doped YNbO_(4)phosphors.Pumped current versus up-conversion emission intensity study shows that two-photon processes are responsible for both the green and the red up-conversion emissions of Er^(3+)ion.Through the study of the temperature sensing property of Er^(3+) ion,it is affirmed that the temperature sensitivity is sensitive to the doping concentration of Bi^(3+) ions.By comparing the experimental values of the radiative transition rate ratio of the two green emission levels of Er^(3+) ions and the theoretical values calculated by Judd-Ofelt(J-O)theory,it is concluded that the temperature sensing property of Er^(3+) ions is greatly affected by the energy level splitting.

320-fold luminescence enhancement of [Ru(dpp)3]Cl2 dispersed on PMMA opal photonic crystals and highly improved oxygen sensing performance

Ru complexes([Ru(dpp)3]Cl2)were spin coated on poly(methyl methacrylate)(PMMA)opal photonic crystals(PhCs),and a,320-fold luminescence enhancement was observed compared to that on glass,which is the largest luminescence enhancement of dye molecules by the modulation of three-dimensional(3D)PhCs reported until now.The enhancement mechanism was carefully examined and it was shown that the luminescence of[Ru(dpp)3]Cl2 depended on the molecule concentration and temperature.It can be concluded that the suppressed non-radiative relaxation among the molecules and the field enhancement both contribute significantly to the luminescence enhancement.The PMMA PhC/Ru complex composites were then tested for their intracellular oxygen sensing and cell imaging properties;these composites effectively improved the limit of detection(LOD)and the brightness of the cell images.