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Bismuth vanadate (BiVO4) microcrystals enclosed with up to 42 low and high index facets were synthesized through truncation of BiVO4 octahedral crystals via a simple and highly reproducible hydrothermal method. The size and shape of the truncated BiVO4 crystals could be tuned by varying the acid concentration, reaction temperature and reaction period. Compared to the BiVO4 octahedral crystals without truncation, the 42-faceted ones showed an enhanced photocatalytic activity in the degradation of rhodamine B molecules due to the enhanced charge separation on the exposed low and high index facets. This was confirmed at sub-particle level by the photo-deposition of gold and manganese oxide nanoparticles selectively on hot electron and hole accumulated facets, respectively. Our results will provide a guideline for the synthesis of more efficient BiVO4 and many other multinary metal oxide-based photocatalysts. Moreover, the synthesized microcrystals are perfect materials for the study of photocatalytic property of BiVO4 at single and sub-particle level.

A feasible strategy relies on using heteroatom replacement, namely, chemical modification of an organic compound. Here we present this design concept for donor-acceptor complexes, which involves introducing nitrogen atoms to the middle ring of donor molecules to promote short contacts and reduce steric effect of the mixed framework. These nitrogen-modified complexes can possess a shorter molecular distance besides the mixed-stacking pathway, enlarged π-π interactions, or even a scarce 1:2.5 molar ratio through extra acceptor insertion. As a result, the unique 1:2 complex with nitrogen atoms on the different sides demonstrated stable electron field-effect mobility performance, whereas the binary system with no nitrogen replacement or N atoms on the identical sides displayed poor ambipolar properties. These results confirmed that heteroatom replacement was a powerful molecular design tool to fine-tune the molecular packing of organic donor-acceptor complexes and their corresponding electronic properties.

Different from the intermediate nitrile cyclotrimerization reactions, a new nitrile chain reaction is proposed to interpret the condensation and carbonization process of cyano-based ionic liquids [MCNIm][TFSI] which is used as a model precursor. The nitrile chain reaction forms several oligomers including dimers, trimers and tetramers during the condensation process at low temperature. The results show the oligomers are pyrolyzed to small fragments at high temperature undergoing a variety of cross-linking and recombination to produce more stable benzene and pyridine based polycyclic aromatic groups prior to the final mesoporous carbon material formation. The cyano-based ionic liquids and nitrile chain reaction mechanism readily yields mesoporous carbon with a specific surface area of 1050 m2 g−1 and a high co-doping with N and S and a content of graphitized material. In terms of potential applications, the N, S-codoped mesoporous carbon material facilitates excellent bifunctional electrocatalytic activity toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) comparable to the benchmark of those commercial 20 wt% Pt/C and RuO2 catalysts, respectively. Remarkably, our analyses show bis(trifluoromethanesulphonyl)-imide (TFSI) anions display much better thermal stability than imidazolium cations, which suggests future potential for other functional cations with more thermally stable intermediate polymeric structures.

Fluorescence resonance energy transfer (FRET) is a reliable, sensitive, and robust assay method for detection of many biological targets. However, it generally needs an externally-introduced label to form the donor-acceptor pair, which could alter the accuracy of the detection. To address this issue, we report herein the FRET-based reactive copper ion sensors by using in situ fluorescent proteins (FP) of human urine or blood serum as the energy donor. Using Bull Serum Albumin (BSA) as model proteins, the sensor exhibits a remarkably fluorescence enhancement when BSA binds to the surface of copper clusters (Cu NCs) base on electrostatic interaction. Conversely, low fluorescence enhancement is observed without using BSA. As proof-of-principle, this positive approach is directly applied to detect Cu2+ using urine as the energy donor, accompanying with a signal enhancement by two factors and low detection limit of 0.5 μM Cu2+. Moreover, the proposed sensor could be applied in other complex environments, such as blood serum or cell culture medium. Consequently, the effectiveness, simplicity and diversity of our proposed strategy enable the development of a class of probes toward complex human environment for rapid, sensitive, and selective detection of targets.

Since the discovery of surface enhanced Raman scattering (SERS), the choice of SERS-active materials has been limited mainly to metals, especially gold and silver in the visible spectrum. Although non-metals can also be SERS-active by forming nanostructures or composite structures with SERS-active materials, the mechanism behind it is still unclear and there is no perfect technique to study it. In this work, by constructing a SERS structure on a flexible polydimethylsiloxane film, we provide a way to study the effect of non-metallic nanostructures on Raman enhancement by attaching the above film onto flat and nanostructured surfaces. It was found that a nanoporous silicon surface contributes to an additional, up to five times, Raman enhancement. The pore depth and pore size also influence the observed Raman enhancement. These findings will help us not only to understand the mechanism of SERS involving non-metallic nanostructures, but also to design more efficient SERS structures for various applications.

We report valence band electronic structure evolution of graphene oxide (GO) upon its thermal reduction. Degree of oxygen functionalization was controlled by annealing temperatures, and an electronic structure evolution was monitored using real-time ultraviolet photoelectron spectroscopy. We observed a drastic increase in density of states around the Fermi level upon thermal annealing at ~600 oC. The result indicates that while there is an apparent band gap for GO prior to a thermal reduction, the gap closes after an annealing around that temperature. This trend of band gap closure was correlated with electrical, chemical, and structural properties to determine a set of GO material properties that is optimal for optoelectronics. The results revealed that annealing at a temperature of ~500 oC leads to the desired properties, demonstrated by a uniform and an order of magnitude enhanced photocurrent map of an individual GO sheet compared to as-synthesized counterpart., Comment: 9 pages, 4 figures in physica status solidi (a) 2016

In this contribution, we developed a novel type of IDT-based small molecular acceptor, IDT-Tz, using thiazole as π-bridges. Through employing thiazole units as the π-bridges, nitrogen⋯sulfur noncovalent conformational locks were introduced to enhance the rigidity and planarity of the backbone, and thus reduce the reorganization energy, increase the charge transport mobility, and enhance the photovoltaic performance. The differences between the IDT-Tz and IDT-T based solar cells were fully investigated to understand the influences of the nitrogen⋯sulfur noncovalent conformational locks. The organic solar cells based on the IDT-Tz electron acceptor exhibit power conversion efficiencies (PCEs) as high as 8.4%, which is significantly higher than the PCE (4.1%) of the IDT-T based devices. This work demonstrated a novel strategy for enhancing the PCE of organic solar cells through introducing noncovalent conformational locks, which will be promising in designing novel high-performance non-fullerene materials.

Caryota obtusa is an endangered and economically important species of the Arecaceae. The complete chloroplast genome sequence of this species is a circular molecule of 159,882 bp in size, including...

Developing simple and cost-efficient methods for fabricating molecular patterns is of great importance in the field of nanoscience and nanotechnology. Here, a simple and convenient method was developed for fabricating nanopatterns composed of positively charged silane molecules by using silver nanowires as templates. The as-obtained silane pattern copies the shape of the silver nanowires and is only 0.7 nm thick, which can later be used for templated assembly of small molecules and nanoparticles of opposite charges. As a proof of concept, the resultant assembly could be further used for surface-enhanced Raman scattering. ispartof: CHEMISTRY-A EUROPEAN JOURNAL vol:25 issue:45 pages:10561-10565 ispartof: location:Germany status: published

Molecular spectroscopic and intensity modulated photocurrent spectroscopy (IMPS) imaging techniques are used to map morphology-dependent charge recombination in organic polymer/fullerene solar cells. IMPS uses a small (∼10%) sinusoidal modulation of an excitation light source and photocurrent responses are measured while modulation frequencies are swept over several decades (∼1 Hz-20 kHz). Solar cells consisting of either poly(3-hexylthiophene) (P3HT) and poly(2-methoxy-5-(3'-7'-dimethyloctyloxy)-1,4-phenylenevinylene) (MDMO-PPV) blended with a soluble fullerene derivative, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) are used as targets. The morphologies of these polymer/fullerene systems are distinctly different due to PCBM miscibility in various polymer conformers. IMPS responses of both blend solar cells show unique morphology-dependent charge generation, transport and extraction signatures that can be spatially correlated to microscopic variations in local composition and packing by constructing IMPS images along with corresponding molecular spectroscopic imaging over the same scan area. We find that boundaries separating enriched polymer and fullerene domains promote nongeminate charge recombination appearing as positive phase shifts in the IMPS response. These zones are susceptible to degradation and we propose the approaches herein can be used to probe material and device degradation in situ under various conditions, such as oxygen content, temperature and ionizing radiation.

Asymmetrical isomerization with prochiral π-distortion is useful to precisely construct nonplanar arenes as promising wide band gap (>2.2 eV) semiconductors. A series of asymmetrical benzoacridine regioisomers (ADs) were designed and obtained via a two-step procedure including Ullmann C-N coupling, intramolecular Friedel-Crafts ortho -aroylation. Interestingly, crystallization induced enantiomer division (CIED) of four prochiral ADs was observed. The corresponding ten divided enantiomers or diastereoisomers were carefully anatomized and distinguished from their “monozygotic and/or dizygotic twins” in crystals. The precise structures of four ADs were confirmed by 1 H NMR, 13 C NMR, HiRes MALDI-TOF MS, FT-IR and single crystal X-Ray diffraction. According to the absorbance spectra, ADs possess wide optical band gaps (2.90–2.98 eV) in film state and potential ability for high performed electronic devices.

Corollas (or perianths), considered to contribute to pollinator attraction during anthesis, persist after anthesis in many plants. However, their post-floral function has been little investigated within a cost-benefit framework. We explored the adaptive significance of corolla retention after anthesis for reproduction in Fritillaria delavayi, a perennial herb endemic to the alpine areas of the Hengduan Mountains, southwestern China. We examined whether the persistent corollas enhance reproductive success during seed development. Persistent corollas increased fruit temperature on sunny days, and greatly decreased the intensity of ultraviolet-B/C (UV-B/C) radiation reaching fruits. When corollas were removed immediately after pollination, fecundity and progeny quality were adversely affected. Measurements of flower mass and size showed no further corolla growth during fruiting, and respiration and transpiration tests demonstrated that both respiration rate and transpiration rate of corollas were much lower during fruiting than during flowering, indicating a slight additional resource investment in corolla retention after anthesis. Thus, seed production by F. delavayi may be facilitated by corolla retention during seed development at only a small physiological cost. We conclude that corolla retention may be an adaptive strategy that enhances female reproductive success by having a protective role for ripening seeds in the harsh conditions at high elevation.

Exploring low-cost and efficient electrocatalysts based on earth-abundant elements for the hydrogen evolution reaction (HER) is of great importance for the development of clean and renewable energy. In this work, we report a facile self-foaming strategy for synthesis of hierarchically interconnected nitrogen-doped carbon nanosheets (NCNS). The doping N species within the 3D interconnected carbon network affords rich active sites for the HER and facilitates fast charge transfer. As a result, the NCNS exhibit excellent catalytic activity with an onset potential of −65 mV, and a Tafel slope of 81 mV dec−1 with robust stability over 10 h in acidic media. Further analyses suggest that the graphitic N species in the NCNS contribute to their catalytic activity. Such a high catalytic performance makes the NCNS a promising metal-free HER electrocatalyst for practical hydrogen production.

International audience; Polymer semiconductors have recently attracted considerable attention owing to their (i) excellent optical properties, (ii) processability, (iii) inherent tunability of the energetics, and (iv) synthetic versatility. Consequently, researchers have shown great interest in developing eco-friendly polymerization methods to reduce the synthetic cost of such macromolecular materials, including the so-called direct (hetero)-arylation polymerization (DHAP). In addition to reducing the number of synthetic steps, required in conventional cross-coupling polymerizations, DHAP avoids the use of lithiated and/or stannylated intermediates that are highly toxic and/or dangerous. In this contribution, we reviewed a number of conjugated polymers prepared by DHAP for applications in organic electronics, and more precisely for organic photovoltaics and field-effect transistors. Moreover, emphasis has been put on polymerization reaction conditions (i.e., the nature of the catalysts, ligands and solvents) and their impact on the properties of the material. Even though some optimizations still remain, regarding the current trends, it is obvious that DHAP will play a larger role in the design and synthesis of polymer semiconductors.

Performing time-tagged, time-correlated, single-photon-counting studies on individual colloidal nanocrystal quantum dots (NQDs), the evolution of photoluminescence (PL) intensity-fluctuation behaviors in near-infrared (NIR) emitting type II, InP/CdS core-shell NQDs is investigated as a function of shell thickness. It is observed that Auger recombination and hot-carrier trapping compete in defining the PL intensity-fluctuation behavior for NQDs with thin shells, whereas the role of hot-carrier trapping dominates for NQDs with thick shells. These studies further reveal the distinct ramifications of altering either the excitation fluence or repetition rate. Specifically, an increase in laser pump fluence results in the creation of additional hot-carrier traps. Alternately, higher repetition rates cause a saturation in hot-carrier traps, thus activating Auger-related PL fluctuations. Furthermore, it is shown that Auger recombination of negatively charged excitons is suppressed more strongly than that of positively charged excitons because of the asymmetry in the electron-hole confinement in type II NQDs. Thus, this study provides new understanding of how both NQD structure (shell thickness and carrier-separation characteristics) and excitation conditions can be used to tune the PL stability, with important implications for room-temperature single-photon generation. Specifically, the first non-blinking NQD capable of single-photon emission in the near-infrared spectral regime is described.

To build on the research of strategic management we conducted an empirical study in the context of international performance. Three principal strategies, according to Porters generic strategy theory: cost leadership cost-focus and differentiation respectively, were tested in our research model. Quantitative empirical analysis of international strategy on a sample of 58 Chinese firms was conducted to determine strategies that lead to enhanced strategic performance. We utilized survey strategy encompassing questionnaire data collection. The collected data was analyzed using SPSS statistical package. Inference statistics consisting of correlation analysis and multiple regression analysis were performed. Findings of the study suggest that cost leadership and differentiation strategies impact strategic performance significantly, whereas cost-focus does not. A value of appropriate international business strategy is illustrated by supporting a relationship between strategy and international performance. The originality of contributions of the study lies in the fact that the generic business strategies’ impact on strategic performance is tested on an international market on the sample of Chinese firms. These notions enrich existing body of knowledge on strategic management. Therefore, companies conducting their business operations internationally should consider forming and implementing strategies of differentiation and cost leadership to achieve optimal business results.

// Yongqian Gao 1, * , Jinyi Li 2, * , Na Qiao 3, * , Qingsong Meng 3 , Ming Zhang 3 , Xin Wang 3 , Jianghua Jia 3 , Shuwen Yang 3 , Changbao Qu 3 , Wei Li 3 , Dongbin Wang 3 1 Department of Interventional Radiology, Tangshan Gongren Hospital, Hebei Medical University, Tangshan 063000, P.R. China 2 Department of Urology, Icahn School of Medicine at Mount Sinai, New York, 10029, USA 3 Department of Urologic Surgery, The Second Hospital of Hebei Medical University, Shijiazhuang, 050000, China * These authors contributed equally to this work Correspondence to: Dongbin Wang, email: dongbin.wang@outlook.com Keywords: renal cell carcinoma, adrenomedullin, tyrosine kinase inhibitor, ERK Received: April 29, 2016 Accepted: August 13, 2016 Published: August 22, 2016 ABSTRACT Purpose: To evaluate the mechanisms underlying sunitinib resistance in RCC and to identify targets that may be used to overcome this resistance. Results: Reanalysis of transcriptome microarray datasets (GSE64052 and GSE76068) showed that adrenomedullin expression was increased in sunitinib-resistant tumors. And adrenomedullin expression was increased in sunitinib-resistant tumor xenografts, accompanied by upregulation of phospho-ERK levels. However, blocking adrenomedullin inhibited sunitinib-resistant tumor growth. Treatment of RCC cells with sunitinib and ADM22-52 was superior to monotherapy with either agent. Additionally, adrenomedullin upregulated cAMP and activated the ERK/MAPK pathway, promoting cell proliferation, while knockdown of adrenomedullin inhibited RCC cell growth and invasion in vitro . Materials and methods: We searched the Gene Expression Omnibus (GEO) database to find data regarding sunitinib-resistant RCC. These data were subsequently reanalyzed to identify targets that contribute to sunitinib resistance, and adrenomedullin upregulation was found to mediate sunitinib resistance in RCC. Then, we created an RCC mouse xenograft model. Mice were treated with sunitinib, an adrenomedullin receptor antagonist (ADM22-52), a MEK inhibitor (PD98059) and different combinations of these three drugs to investigate their effects on tumor growth. RCC cells (786-0) were cultured in vitro and treated with an ADM22-52 or PD98059 to determine whether adrenomedullin activates the ERK/MAPK pathway. Adrenomedullin was knocked down in 786-0 cells via siRNA, and the effects of this knockdown on cell were subsequently investigated. Conclusions: Adrenomedullin plays an important role in RCC resistance to sunitinib treatment. The combination of sunitinib and an adrenomedullin receptor antagonist may result in better outcomes in advanced RCC patients.

With the rapid decline in cost of sequencing, it is now affordable to examine multiple genes in a single disease-targeted clinical test using next generation sequencing. Current targeted sequencing methods require a separate step of targeted capture enrichment during sample preparation before sequencing. Although there are fast sample preparation methods available in market, the library preparation process is still relatively complicated for physicians to use routinely. Here, we introduced an amplification-free Single Molecule Targeted Sequencing (SMTS) technology, which combined targeted capture and sequencing in one step. We demonstrated that this technology can detect low-frequency mutations using artificially synthesized DNA sample. SMTS has several potential advantages, including simple sample preparation thus no biases and errors are introduced by PCR reaction. SMTS has the potential to be an easy and quick sequencing technology for clinical diagnosis such as cancer gene mutation detection, infectious disease detection, inherited condition screening and noninvasive prenatal diagnosis.

We fabricate poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) thin film solar cells of variable weight/weight (w/w) compositions (i.e., 1:1 to 1:4) to systematically perturb polymer packing (aggregation) properties and assess their impact on local electronic structure and photocurrent generation efficiency. A combination of absorption spectroscopy and resonance Raman spectroscopic and photocurrent imaging techniques are used to quantify and spatially map morphology-dependent cofacial, π−π aggregated P3HT chains and correlate these structures to local photocurrent production characteristics. On average, increasing the PCBM weight fraction results in blue shifts and broadening for absorption and Raman spectra in the dominant P3HT C═C stretching mode region (∼1450−1470 cm−1), whereas symmetric stretching C—C modes show decreased intensities and red shifts. P3HT/PCBM absorption spectra are fitted near the resolved P3HT onset region using a weakly coupled H-aggregate model th...

Resonance Raman−photocurrent imaging (RRPI) is introduced to spatially map the morphology-dependent polymer aggregation state to local photocurrent generation efficiency in poly-(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blend thin film photovoltaic devices. The C═C symmetric stretching mode of P3HT is decomposed into contributions from aggregated (IC═Cagg, ∼1450 cm−1) and unaggregated (IC═Cun, ∼1470 cm−1) chains, and the ratios of their integrated intensities (IC═Cagg/IC═Cun, R) is used as a reporter for the local P3HT aggregation state. Maps of R values and photocurrents are generated for both as-cast and annealed P3HT/PCBM devices that permit direct spatial correlations between the P3HT aggregation state and local photocurrent generation efficiency. Regions of increased P3HT aggregation are observed at both P3HT/PCBM interfaces and in P3HT-rich areas that result in decreased photocurrent generation. Voltage-dependent RRPI studies are also performed at several applie...

The cubic β-In2S3 hollow nanospheres was fabricated via two-step solvothermal approaches using InCl3·4H2O, CS2, and thioacetamide (C2H5NS) as the starting materials. The as-prepared cubic β-In2S3 possessed hollow nanosphere structures, whose outward diameters and shells are −75 and 20 nm, respectively. The samples were characterized by XRD, FESEM, TEM, SAED, and HRTEM. The optical properties of the cubic β-In2S3 hollow nanospheres were also investigated. UV–vis (280 nm) and PL (367 nm) spectra indicate that there exists obvious blue shift compared with the In2S3 bulk materials.

With the rapid decline cost of sequencing, it is now clinically affordable to examine multiple genes in a single disease-targeted test using next generation sequencing. Current targeted sequencing methods require a separate step of targeted capture enrichment during sample preparation before sequencing, and the library preparation process is labor intensive and time consuming. Here, we introduced an amplification-free Single Molecule Targeted Sequencing (SMTS) technology, which combined targeted capture and sequencing in one step. We demonstrated that this technology can detect low-frequency mutations of cancer genes. SMTS has several advantages, namely that it requires little sample preparation and avoids biases and errors introduced by PCR reaction. This technology can be applied in cancer gene mutation detection, inherited condition screening and high-resolution human leukocyte antigen (HLA) typing.

High yield hausmannite (Mn3O4) nanorods with diameters of about 100 nm and lengths up to 15–20 µm have been prepared by vacuum calcining of the precursor (Mn3O4+MnOOH), which was hydrothermally prepared by the reaction of PEG-20000 and KMnO4 at 180 °C for 20 h. Transmission electron microscopy and the selected-area electron diffraction pattern reveal that these Mn3O4 nanorods show single-crystal growth along the [100] direction. The PEG-20000 and the calcination conditions have key effects on the morphology and phase purity of the product. Magnetism measurements show that the blocking temperature for these Mn3O4 nanorods is 41 K, which agrees with the bulk material value, whereas the remnant magnetization and coercivity are 0.89 μB and 6177 Oe respectively.

The alpha-MnO2 nanocrystal nanowires, nanoplates, and nanoflowers have been successfully synthesized by a common hydrothermal treatment of different solutions containing KMnO4 and NH4X (X = Cl-, Ac-, NO3-, SO4(2-), and PO4(3-)) at 140 degrees C for 24 h. The influence of anions on the morphology of final product is discussed. According to our experimental results, we proposed a possible mechanism of the formation of different morphologies of nano-phase alpha-MnO2 and considered that the growing process was due to the initial plate-like MO(x) absorbing different anions and cooperation with them, which contributes to the final morphology of the product.

A two-step synthesis method was developed to fabricate Mn-doped zinc aluminate (ZnAl2O4) nanoparticles, including the first step of ageing, and the second step of crystallization. The effects of preparation conditions, such as ageing temperature, crystallization time, and the pH on the Mn-doped ZnAl2O4 nanoparticles were systematically investigated. The photoluminescence (PL) properties of green phosphor Mn-doped ZnAl2O4 nanoparticles were also discussed. Compared with the bulk sample, the PL spectrum of Mn-doped ZnAl2O4 nanoparticles has distinct blue shift. This procedure provides a facile way for the synthesis of well-crystallized ZnAl2O4:Mn at low temperature.

A large number of one-dimensional bundles of ZnSe nanowires with diameters ranging from 15-20 nm and lengths of up to tens of micrometers have been prepared via the thermal treatment of a ribbon-like precursor (ZnSe-3ethylenediamine), which has been synthesized by a mixed solvothermal route, in an argon atmosphere. The as-obtained precursor has been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), IR spectroscopy, thermogravimetric analysis, and elemental analysis. XRD and high-resolution TEM characterization reveal that the as-synthesized ZnSe nanowires have the single-crystal hexagonal wurtzite structure with the [001] growth direction. The surface chemical composition of ZnSe nanowires has been studied by X-ray photoelectron spectroscopy. The cooperative action of the mixed solvents may be responsible for the formation of the morphology of the resulting products. Room-temperature photoluminescence measurements indicate the as-grown ZnSe nanostructures have a strong emission peak centered at 587 nm and two weak emission peaks centered at 435 and 462 nm. The strong emission from the ZnSe nanostructures reveals their potential as building blocks for optoelectronic devices.

Single-crystalline α -MnO2 nanowires with diameters of 10–30 nm and lengths ranging from 6 to 10 μm have been successfully synthesized by hydrothermal treating a mixed solution of KMnO4 and NH4Cl at 140 °C for 24 h. The final products were characterized by XRD, FESEM, TEM and HRTEM. The effect of anion Cl− in the possible rolling formation mechanism was also briefly discussed.

The manner in which polymer chains pack and organize in thin film structures is crucial to maximizing the efficiency of charge and energy transport processes in solar cell devices. We use new spectroscopic and electrical imaging tools to spatially map and correlate local structure (chain conformation, packing, morphology) to local photocurrent generation efficiency. Both Raman and photoluminescence approaches are used that provide unique insights into important structural attributes and how they vary with film morphology. Simultaneous electrical measurements are then used to establish the roles of specific structural features to photocurrent production.

Resonance Raman spectroscopic imaging is introduced as a physical probe to identify and spatially map morphology-dependent variations of intra- and interchain interactions and order in poly-3-hexylthiophene (P3HT) and [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM) photovoltaic blend thin films. Absorption spectra and C=C symmetric stretching Raman modes of P3HT/PCBM blend films show contributions from two distinct species that are assigned as aggregated and unaggregated P3HT chains with characteristic Raman frequencies of approximately 1450 (I(C=C)(agg)) and approximately 1470 cm(-1) (I(C=C)(un)), respectively. Upon thermal annealing of blend films, the relative concentrations of I(C=C)(agg) and I(C=C)(un) species (R = I(C=C)(agg)/I(C=C)(un)) changes on average from 0.79 +/- 0.20 (as-cast) to 2.45 +/- 0.77 (annealed). It is proposed that R values report on the relative densities of states (DOS) of aggregated and unaggregated species, and resonance Raman imaging is then used to spatially map morphology-dependent variations of R values and uncover subclassifications of these species. From both R and frequency dispersion resonance Raman images of I(C=C)(agg) and I(C=C)(un) species, four distinct types of P3HT chains are identified and mapped in annealed P3HT/PCBM blend thin films: (i) highly aggregated/crystalline, (ii) partially aggregated, (iii) interfacial, and (iv) unaggregated/PCBM rich. The change in aggregation upon annealing is attributed to an increase in planarity of the P3HT chains that is determined from the ratios of C=C/C-C symmetric stretching mode intensities.

The alpha-MnO2 nanocrystal nanowires, nanoplates, and nanoflowers have been successfully synthesized by a common hydrothermal treatment of different solutions containing KMnO4 and NH4X (X = Cl-, Ac-, NO3-, SO4(2-), and PO4(3-)) at 140 degrees C for 24 h. The influence of anions on the morphology of final product is discussed. According to our experimental results, we proposed a possible mechanism of the formation of different morphologies of nano-phase alpha-MnO2 and considered that the growing process was due to the initial plate-like MO(x) absorbing different anions and cooperation with them, which contributes to the final morphology of the product.

Hollow SnO2 nanospheres with diameters ranging from 100–120 nm have been synthesized via a room-temperature wet-chemical route. A possible formation mechanism of the hollow SnO2 nanospheres is brie...