Visualization 1: Highly efficient plasmonic enhancement of graphene absorption at telecommunication wavelengths

Distribution of magnetic field. Originally published in Optics Letters on 01 August 2015 (ol-40-15-3647

Reversible Thermochromic Perovskite-Based Dynamic Optical Encryption and Holographic Inference

Perovskites have attracted extensive attention in the field of nanophotonics with a plethora of applications owing to their high optical constants, tunable band gap, solution processability, and large optical tunability. In this work, we demonstrate perovskite-based dynamic photonic devices for applications of optical encryption and holographic inference by femtosecond laser patterning all-inorganic mixed halide perovskite CsPbIBr2 with thermochromic features. During one cycle of moisture and evaporation treatment, the CsPbIBr2 perovskite pattern undergoes a reversible conversion between a bright red (high-T) phase and a colorless transparent (low-T) phase, accompanied by significant optical state changes, resulting in on/off functionality switch. At a low-T state, the encoded fluorescent or holographic information is hidden, and the function of optical inference is invalid. Conversely, at a high-T state, the encrypted information is reconstructed, and the ability of holographic inference is reactivated. Moreover, the perovskite photonic devices exhibit outstanding operating stability after 10 repeated conversion cycles without prominent performance degradation. Such perovskite photonic devices not only provide a novel approach to realize dynamic control of the desired optical functions but also have huge applicable potential for diverse optical applications, such as optical encryption, optical anticounterfeiting, and optical artificial intelligence

Adsorption Equilibrium of CO₂ and CH₄ and Their Mixture on Sichuan Basin Shale

Adsorption equilibrium isotherms of CO₂, CH₄, and mixtures of CO₂/CH₄ on shale sampled from Nanchuan, southeastern Sichuan Basin, were measured at 278, 298, and 318 K by an accurate gravimetric method. The adsorption equilibrium data of CO₂ and CH₄ were fitted using both the virial model and the Brunauer–Emmett–Teller (BET) model, and the isotherms of CO₂/CH₄ mixtures were fitted by an extended BET model. On the basis of adsorption data, the adsorption selectivity factors for CO₂ over CH₄ (α_CO₂/CH₄) and thermodynamic parameters were estimated. Nanchuan shale was characterized with a high total organic carbon (TOC), having inorganic minerals and wide pore size distribution ranges. The adsorption heat, negative Gibbs free energy change, and negative surface potential of CO₂ are larger than those of CH₄, and the entropy loss of CO₂ is larger than that of CH₄, suggesting that adsorbed CO₂ is in a more highly ordered arrangement than CH₄ on shale. α_CO₂/CH₄ values at different temperatures are all larger than 2.5

Total Synthesis of Aphadilactones A–D

The first total synthesis of aphadilactones A–D, diastereomeric natural products recently isolated from the Meliaceae plant <i>Aphanamixis grandifolia</i> by Yue and co-workers, which possess an unprecedented carbon skeleton, has been achieved. The synthesis features a catalytic asymmetric hetero-Diels–Alder reaction to form the dihydropyran ring, concurrent installation of the lactone and furan moieties via a tandem acid-catalyzed acetal cleavage, oxidation, and cyclization process, and an intermolecular Diels–Alder reaction to forge the target products

Synthesis of ZnO Nanoparticles with Controlled Shapes, Sizes, Aggregations, and Surface Complex Compounds for Tuning or Switching the Photoluminescence

The electronic energy transfer (EET) usually induces the fluorescence self-quenching, but it has been positively used here to tune and/or switch the photoluminescence (PL) of ZnO nanoparticles (NPs). Monodisperse ZnO nanospheres, rods, tripods, and clusters with tunable sizes have been synthesized to reproducibly and finely control the NP aggregation because EET is sensitive to the interparticle separation. The complex reactions between these NPs and their dispersion media have been used to further control the EET for tuning the ZnO PL. By changing the NP concentrations, shapes, and/or the cluster sizes, the band-edge UV PL of the ZnO NPs dispersed in alcohol or water is modified in both intensity and peak position, and new blue emissions with tunable intensity around 418, 435, and 468 nm are induced. As confirmed by the X-ray diffraction patterns and the infrared, PL, absorption, and Raman spectra, the ZnO NPs made here can slowly react with ethanol to form a new composite ZnO–(C₂H₅OH)_<i>n</i>, which changes the EET between NPs and leads to strong blue PL around 435 nm. By simply using different dispersion media (such as ethanol or water) to modify the surface complex compounds of ZnO NPs, the 435 nm blue PL can be turned on or off

Optical/Electrical Integrated Design of Core–Shell Aluminum-Based Plasmonic Nanostructures for Record-Breaking Efficiency Enhancements in Photovoltaic Devices

Recently plasmonics has gained tremendous interest in solar cell research because it is capable of improving sunlight-conversion efficiencies. However, plasmonic photovoltaic nanostructures with both excellent optical properties and high electrical conductivities have not been developed, thus limiting the efficiency breakthrough. In this paper, we present an optical/electrical integrated design for plasmonic photovoltaic nanostructures by synthesizing core–shell nanomaterials: aluminum-coated copper nanoparticles. A copper nanocore was synthesized by chemical methods, and then an aluminum nanoshell was physically deposited on the nanocore surface. Strong light-scattering properties have been demonstrated due to the controllable morphology of the nanoparticles and the UV plasmon response of the aluminum nanoshells. Ultrahigh electrical conductivities have been achieved by the pure metallic nanoshells. Once the aluminum-based core–shell particles were integrated into high-efficiency amorphous silicon solar cells, we demonstrated a tremendous efficiency enhancement of 15.4%, which is 51% higher than that from the state-of-the-art plasmonic technique using silver nanostructures

Supplement 1: Multifocal optical nanoscopy for big data recording at 30 TB capacity and gigabits/second data rate

Originally published in Optica on 20 June 2015 (optica-2-6-567

Synthesis of ZnO Nanoparticles with Controlled Shapes, Sizes, Aggregations, and Surface Complex Compounds for Tuning or Switching the Photoluminescence

The electronic energy transfer (EET) usually induces the fluorescence self-quenching, but it has been positively used here to tune and/or switch the photoluminescence (PL) of ZnO nanoparticles (NPs). Monodisperse ZnO nanospheres, rods, tripods, and clusters with tunable sizes have been synthesized to reproducibly and finely control the NP aggregation because EET is sensitive to the interparticle separation. The complex reactions between these NPs and their dispersion media have been used to further control the EET for tuning the ZnO PL. By changing the NP concentrations, shapes, and/or the cluster sizes, the band-edge UV PL of the ZnO NPs dispersed in alcohol or water is modified in both intensity and peak position, and new blue emissions with tunable intensity around 418, 435, and 468 nm are induced. As confirmed by the X-ray diffraction patterns and the infrared, PL, absorption, and Raman spectra, the ZnO NPs made here can slowly react with ethanol to form a new composite ZnO–(C₂H₅OH)_<i>n</i>, which changes the EET between NPs and leads to strong blue PL around 435 nm. By simply using different dispersion media (such as ethanol or water) to modify the surface complex compounds of ZnO NPs, the 435 nm blue PL can be turned on or off

Investigation on Relaxational Behavior of Alkylammonium Ions Intercalated in Graphite Oxide

Graphite oxide (GO) nanocomposites have been synthesized to contain various concentrations of intercalated alkylammonium ions and characterized with X-ray diffraction, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and differential scanning calorimetry. Depending on their concentration, the alkyl chains may lie parallel to the GO plane one or two layers thick or they form two columns inclined at an angle ∼37° to the plane. Dielectric spectroscopy reveals a relaxation process far below room temperature, attributed to small-angle wobbling around the long molecular axis. The activation energy of this relaxation increases as the intercalate changes from one to two layers, and to dual columns, with increasing interactions among the intercalated molecules. An additional phase transition occurs in composites with high concentrations of intercalate between a rotator-type solid phase to a disordered phase for the confined alkyl chains

shRNA-Mediated Silencing of Y-Box Binding Protein-1 (YB-1) Suppresses Growth of Neuroblastoma Cell SH-SY5Y <i>In Vitro</i> and <i>In Vivo</i>

<div><p>Y-box binding protein-1 (YB-1), a member of cold-shock protein superfamily, has been demonstrated to be associated with tumor malignancy, and is proposed as a prognostic marker in multiple carcinomas. However, the role of YB-1 in neuroblastoma has not been well studied. To investigate the functional role of YB-1 in neuroblastoma, we established a YB-1-silenced neuroblastoma cell strain by inhibiting YB-1 expression using a shRNA knockdown approach. YB-1-silenced neuroblastoma SH-SY5Y cells exhibited a pronounced reduction in cell proliferation and an increased rate of apoptosis <i>in vitro</i> and <i>in vivo</i> xenograft tumor model. At molecular level, YB-1 silencing resulted in downregulation of Cyclin A, Cyclin D1 and Bcl-2, as well as upregulated levels of Bax, cleaved caspase-3 and cleaved PARP-1. We further demonstrated that YB-1 transcriptionally regulated Cyclin D1 expression by chromatin-immunoprecipitation and luciferase reporter assays. In addition, xenograft tumors derived from neuroblastoma SH-SY5Y cell line were treated with YB-1 shRNA plasmids by intra-tumor injection, and YB-1 targeting effectively inhibited tumor growth and induced cell death. In summary, our findings suggest that YB-1 plays a critical role in neuroblastoma development, and it may serve as a potential target for neuroblastoma therapy.</p></div