Shell Species Research Articles

Niche overlap and resource partitioning between two intertidal hermit crab species

The gastropod shell influences important aspects of the hermit crab's life; however, the shells are commonly a limited resource. Therefore, different hermit crab species that coexist in intertidal areas are commonly involved in intraspecific and interspecific competition for shells. We assess if differences in shell preference, exploitation ability, or competition by interference can explain the partitioning of shells between the coexisting species Calcinus californiensis and Clibanarius albidigitus. Clibanarius preferred shells of Nerita funiculata among the six gastropod shells tested, while Calcinus did not establish a hierarchy in shell preference. Therefore, the preference for gastropod shell species does not seem to diminish the competition for shells in the wild. Clibanarius identified and attended to chemical cues signalling potential sites of available shells (chemical cues of dead gastropods); Calcinus did not respond to these cues (competition by exploitation). However, Calcinus was more successful in obtaining a new shell by interspecific shell fighting than Clibanarius. Consequently, the use of better quality shells (intact shells) by Calcinus in the wild can be explained by its greater fighting ability compared with Clibanarius. The bias in shell distributions through dominance by shell fighting, more than by exploitation ability, has also been suggested for other hermit crab species of these genera.

Core-shell nickel catalysts for the steam reforming of acetic acid

To obtain a novel catalyst with high resistances to metal sintering and coke formation in the steam reforming of acetic acid, a series of nickel core-shell catalysts were prepared. The effects of the shell thickness, shell species and core particle size on the catalytic activity in the steam reforming of acetic acid were investigated. The prepared Ni@SiO2, Ni@Al2O3, Ni@CeO2 and Ni@TiO2 catalysts were characterized by BET, XRD, H2-TPR, DTG and HRTEM. The prepared core-shell catalysts showed high resistances to nickel sintering, owing to the protection of the shells, in comparison with bare nickel particles. Ni@SiO2 with a thin shell showed a higher activity than the corresponding catalyst with a thick shell due to the thin silica shell allowing the facile diffusion of reactants and products. Because of the important role of the support in steam reforming reactions, the shell species greatly affected the catalytic activity in the steam reforming of acetic acid. It was demonstrated that an alumina shell was best suited for the steam reforming of acetic acid among the studied shells owing to its excellent water dissociation ability. The Ni@Al2O3-i catalyst showed excellent activity with an almost complete conversion and a hydrogen yield up to 91.2% at 750°C due to its much smaller nickel particle size. The coke formed on the spent core-shell catalysts after the activity tests was mainly graphic carbon, and the Ni@Al2O3-i catalyst exhibited a superior coke resistance with the smallest amount of formed coke. HRTEM results of Ni@Al2O3-i indicated the alumina shell had a high hydrothermal stability and further confirmed the high sintering resistance in the steam reforming of acetic acid.

Well-Dispersed Nanoscale Zero-Valent Iron Supported in Macroporous Silica Foams: Synthesis, Characterization, and Performance in Cr(VI) Removal

Well-dispersed nanoscale zero-valent iron (NZVI) supported inside the pores of macroporous silica foams (MOSF) composites (Mx-NZVI) has been prepared as the Cr(VI) adsorbent by simply impregnating the MOSF matrix with ferric chloride, followed by the chemical reduction with NaHB4 in aqueous solution at ambient atmosphere. Through the support of MOSF, the reactivity and stability of NZVI are greatly improved. Transmission electron microscopy (TEM) results show that NZVI particles are spatially well-dispersed with a typical core-shell structure and supported inside MOSF matrix. The N2 adsorption-desorption isotherms demonstrate that the Mx-NZVI composites can maintain the macroporous structure of MOSF and exhibit a considerable high surface area (503 m2·g−1). X-ray photoelectron spectroscopy (XPS) and powder X-ray diffraction (XRD) measurements confirm the core-shell structure of iron nanoparticles composed of a metallic Fe0 core and an Fe(II)/Fe(III) species shell. Batch experiments reveal that the removal efficiency of Cr(VI) can reach 100% when the solution contains 15.0 mg·L−1 of Cr(VI) at room temperature. In addition, the solution pH and the composites dosage can affect the removal efficiency of Cr(VI). The Langmuir isotherm is applicable to describe the removal process. The kinetic studies demonstrate that the removal of Cr(VI) is consistent with pseudo-second-order kinetic model.

Shell and gravel layers caused by storm-induced rip currents during the Medieval Warm Period and Little Ice Age in South Korea

Five shell-gravel layers (2.2–2.9m in elevation, 70cm in thickness) formed by storm-induced rip currents along the southern coast of the Korean Peninsula over the past 1300years are described. The three radiocarbon dates (S1–S3) and the two optically stimulated luminescence (S4 and S5) dates correspond well with the succession of the five shell-gravel layers. The age of S1, CE 720±60, corresponds to the early Medieval Warm Period (MWP). The dates of the three overlying layers (S2–S4), CE 880±110, 950±70, and 995±120, respectively, coincide with the middle MWP. The fifth date of the uppermost shell-gravel layer (S5), CE 1535±40, coincides with the Little Ice Age (LIA) of Western Europe. The characteristics of shell habitats based on 16 shell species from each layer suggest that the first four layers formed in a slightly erosional to dominantly depositional environment during the MWP, whereas the youngest layer formed in a dominantly erosional environment during the LIA. Analyses of grain size distribution, magnetic susceptibility, and geochemistry of the sediments, and gravel morphology indicate that storm activity at this site during the MWP and LIA occurred within active storm periods in the western North Atlantic (WNA). Comparison of the five storm events and related climatic factors suggests that, although the typhoon track type at the site is similar to recurving tracks typical for El Niño conditions in North China and Japan, tracks during the MWP and LIA were likely shifted not only by changes in El Niño conditions but by other climatic factors such as sea surface temperature, the North Pacific High, and the westerly jet stream. However, storm energy under El Niño years during the middle MWP was likely stronger than that produced in normal years during the early MWP.

Anthracene and phenanthrene tropospheric oxidation promoted by the nitrate radical in the gas-phase. Theoretical modelistic study

Polycyclic aromatic hydrocarbons and their oxidized derivatives are ubiquitous environmental pollutants that are toxic to different degrees. The NO3 radical is known to be an important actor in fostering nighttime atmospheric chemistry; hence it could elicit some nocturnal PAH-loss processes. In this study the gas phase pathways open to the initial anthracene and phenanthrene NO3 π−radical adducts in the presence of O2, NO and NO2 are examined by Density Functional Theory to ascertain the mechanistic features of their NO3-initiated oxidative degradation. Unimolecular steps involving the initial adducts (ring closures or fragmentation) present rather high free energy barriers and seem unlikely. Regarding bimolecular reactions, any radical present in the tropospheric environment can give an intrinsically fast radical coupling with the initial adducts, thus producing bifunctional closed shell species. The addition of ground state dioxygen is a relatively fast step that is reversible in some cases, less so in others. It entails subsequent reaction steps, which involve the peroxyl radical intermediate and addition and loss of small species as NO, NO3, NO2 and O2. These steps can either trigger a β−fragmentation with formation of a closed shell dialdehyde or formation of a closed shell nitroxy ketone, bifunctional species that appear to be the most likely products when typical tropospheric concentrations are taken into account.

Rational synthesis of core-shell Fe3O4@thermally crosslinked PANI nanostructures based on a PVP-mediated in-situ polymerization strategy: Towards a stable catalyst support for 12-tungstophosphoric acid

Magnetically recoverable heteropoly acids (HPAs) exhibit high activity for oxidation reactions. However, HPA species immobilized onto magnetic supports commonly suffer from the loss of active species into reaction solutions due to the weak affinity of the supports for active species. Herein, core-shell Fe3O4@thermally crosslinked PANI@Tunstophoric acid (Fe3O4@TC-PANI@TPA) nanostructures were rationally synthesized based on a PVP-mediated surface polymerization strategy and a subsequent thermal treatment process. Uniform PANI shell and TPA species were successively deposited onto Fe3O4 nanoclusters, followed by a thermal crosslinked treatment of PANI shell. Spatial confinement of high dispersed TPA sites within thermally crosslinked PANI shell could largely enhance their solvent tolerance against the loss of active TPA sites accompanied by the dissolution of some non-crosslinked PANI chains during catalytic transformations. As expected, the Fe3O4@TC-PANI@TPA catalyst exhibited high activity, facile magnetic recoverability, and robust stability for green epoxidation of cis-cyclooctene using ethanol as a solvent and H2O2 as an oxidant.

Karyotype differentiation in tellin shells (Bivalvia: Tellinidae)

BackgroundAlthough Tellinidae is one of the largest and most diverse families of bivalves, its taxonomy is utterly chaotic. This is mainly due to the morphological diversity and homoplasy displayed by their shells and to the scarcity of the molecular phylogenetic studies performed on them. A molecular cytogenetic analysis of four tellin shell species, Bosemprella incarnata, Macomangulus tenuis, Moerella donacina and Serratina serrata, was performed. To molecularly characterize the analyzed specimens, the sequence of a fragment of the mitochondrial cytochrome c oxidase subunit I (COI) was also studied.ResultsThe karyotypes of the four species were composed of different amounts of bi-armed and telocentric chromosomes. The chromosomal mapping of 45S and 5S rDNA and H3 histone gene clusters by fluorescent in situ hybridization also revealed conspicuous differences on the distribution of these DNA sequences on their karyotypes. Vertebrate type telomeric sequences were located solely on both ends of each chromosome in all four tellin shells.ConclusionWe present clear evidence of the valuable information provided by FISH signals in both analyzing chromosome evolution in Tellinidae and as a further tool in identifying tellin shell specimens for molecular phylogenies.

Invertebrate shells (mollusca, foraminifera) as pollution indicators, Red Sea Coast, Egypt

To assess the degree of pollution and its impact on the environment along the Red Sea Coast, the most abundant nine species of recent benthic foraminifera and three species of molluscan shells have been selected for the analysis of Fe, Mn, Zn, Cu, Pb, Ni, Co, and Cd concentrations. The selected foraminiferal species are: Textularia agglutinans, Amphispsorus hemprichii, Sorites marginalis, Peneroplis planatus, Borelis schlumbergeri, Amphistegina lessonii, Ammonia beccarii, Operculina gaimairdi, and Operculinella cumingii. The selected molluscan shells are: Lambis truncata and Strombus tricornis (gastropods) and Tridacana gigas (bivalves). The inorganic material analysis of foraminifera and molluscs from the Quseir and Safaga harbors indicates that foraminifera tests include higher concentrations of heavy metals such as Fe and Mn than molluscan shells. These results are supported by the black tests of porcelaneous foraminifera and reflect iron selectivity. The Cd and Pb concentrations in molluscan shells are high in the El Esh Area because of oil pollution at this site. The Cu, Zn, and Ni concentrations in the studied invertebrates are high at Quseir Harbor and in the El Esh Area because of the strong influence of terrigenous materials that are rich in these metals. The heavy metal contamination is mostly attributed to anthropogenic sources.

The difference between a rock and a biological hard place: epibionts in the rocky intertidal

In dynamic environments such as the rocky marine intertidal zone, epibiosis may promote the survival of some organisms. We compared the species composition and prevalence of the epibiotic community on different species of molluscan shells to those on neighboring rock at three sites and two tidal heights per site on San Juan Island, Washington (48°N, 123°W; summer 2014). Across all three sites and both tidal heights examined, the algal species dominating the bedrock did not match the dominant epibiotic species. Most epibiotic species were from a subset of the less common bedrock species. Within the lower tidal height, many potential host shells lacked epibionts, but the bedrock was heavily colonized. Our findings suggest that shells do not represent a microhabitat that is more beneficial to settlers than the surrounding bedrock. Epibiosis is unlikely to elevate local species diversity in this ecosystem because the few epibionts were generally from a subset of the species on the bedrock. Smooth-shelled limpets had a significantly greater prevalence of epibiosis in the lower than in the higher tidal height, but the prevalence of epibiosis did not differ significantly between tidal heights for carnivorous, spired-shell species. This variation among basibionts in pattern of prevalence across tidal heights suggests that the carnivorous snails are more likely than the limpets to range across intertidal heights.

Distinctive morphology effects of porous-spherical/yolk-shell/hollow Pd-nitrogen-doped-carbon spheres catalyst for catalytic reduction of 4-nitrophenol

Pd-nitrogen-doped-carbon nanocatalysts (Pd-C/N) with different morphologies, such as porous spheres, yolk-shell and hollow structures, had been synthesized and compared. The yolk-shell Pd-nitrogen-doped-carbon nanocatalysts (YS-Pd-C/N) and hollow Pd-nitrogen-doped-carbon nanocatalysts (H-Pd-C/N) were prepared through different etch time using SiO2 spheres as hard-templates. The as-prepared catalysts were characterized thoroughly by TEM, BET, XRD, FT-IR, and XPS. Importantly, the catalysts have moderate BET specific surface area in the range from 200 to 300m2g−1 and pore volume between 0.2 and 0.3cm3g−1. The reduction of 4-nitrophenol is chosen as a model reaction to research the morphology effects of these prepared Pd-C/N catalysts with the same chemical compositions. Interestingly, H-Pd-C/N exhibited the best catalytic performance, which could be attributed to its high nitrogen content, the uniform distribution of abundant active sites, as well as the synergistic effect of graphitic C/N shell and Pd species for the catalytic reaction. Especially, the unique hollow morphology and porous shell of H-Pd-C/N made it to be a nanoreactor, which was beneficial to improve the catalytic activities. In addition, H-Pd-C/N nanocatalysts exhibited favorable stability in the recycling reactions.

Effects of elevated pCO2 on crab survival and exoskeleton composition depend on shell function and species distribution: a comparative analysis of carapace and claw mineralogy across four porcelain crab species from different habitats

Elevated concentration of carbon dioxide (elevated pCO2) that cause reduced pH is known to influence calcification in many marine taxa, but how elevated pCO2 influences cation composition of mineralized structures is less well studied. To a large extent, the degree to which elevated pCO2 impacts mineralized structures is influenced by physiological adaptation of organisms to environments where low pH is routinely experienced. Here, we test the hypotheses that elevated pCO2 will differently impact the relative concentrations of divalent cations (Ca2+, Mg2+, Sr2+, and Mn2+) in four closely related species of porcelain crabs distributed across intertidal zone gradients. Cation composition of carapace and claw exoskeleton was determined using inductively coupled plasma mass spectrometry following 24-day exposures to pH/pCO2 levels of 8.0/418 and 7.4/1850 µatm during the intermoult period. Reduced pH/elevated pCO2 caused a 13–24% decrease of carapace [Ca2+] across all species, and species-specific responses in carapace and claw [Mg2+], [Sr2+] and [Mn2+] were observed. During a 24-day exposure, reduced pH/elevated pCO2 reduced survival probability in low-intertidal but not mid-intertidal species. Overall, the effect of reduced pH/elevated pCO2 on exoskeleton mineral composition was muted in mid-intertidal species relative to low-intertidal species, indicating that extant adaptation to the variable intertidal zone may lessen the impact of ocean acidification (OA) on maintenance of mineralized structures. Differences in responses to reduced pH/elevated pCO2 among closely related species adds complexity to predictive inferences regarding the effects of OA.

Morphological Variation and Speciation of Acavidae Family: A Case Study from Fossil and Living Species of Batadombalena Cave Pre-historic Site in Sri Lanka

Abstract A sufficient knowledge on prehistoric culture and habitat of earliest Homo sapiens (Balangoda man) is available in Batadomba-lena cave, a noticeable rock shelter in lowland rainforest of southwestern Sri Lanka goes upto Pleistocene and Holocene eras. Late Pleistocene inhabitants of Batadombalena cave’s foraged for a broad spectrum of plant and mainly arboreal animal resources such as, monkeys, squirrels and rainforest snails etc. Archaeo-faunal evidence would help to describe the prehistoric man eating behavior as well as availability of nature pre-historic flora, fauna and environmental status. The family Acavidae is very sensitive to climatic variations, hence used as a bio-indicator to describe the variations of paleo-climatic nature. This study examined the morphological features of 20 samples of Acavidae family (living/fossil samples of Acavus superbus, and sub fossil samples of Oligospira waltoni) collected from soils by digger method in 2005 and compared with 20 samples from the same area at presently available. The shell characters of snails such as, height, width, diameter of mouth, thickness of lip, and angular of axis were measured and subjected to multivariate analysis to understand how climatic variability and nature of paleo-diet contribute survival of Acavidae species. Results showed that Acavus superbus living species had large shell characteristics than the sub fossils. Results of similar study in the same climatic status in 2000 showed that the shell measurements of Acavus superbus are relatively larger than both living and sub fossils in Batadobalena cave. Ordination diagram derived from species shell characteristics showed that Acavus superbus living species grouped as scattered /diffuse clusters, while sub fossil species grouped as a single cluster at the center of the ordination diagram. It is imply a trend of speciation /diversification of Acavus species from Pleistocene era to date. Multivariate analyses prove that, a strong positive correlation of species characteristics, such as height (r = 0.62), thickness of lip (r = 0.544) and angular of axis (r = 0.744), and a strong negative relationship (r = 0.832) for shell width for the species were observed. Our results are useful to compare with other fossil snails to see whether the climate change influence for changing body size. In conclusion, palaeo-environment, and present environment variation has been occurred in minimum way without much changes to observed Acavidae species compositions present and past.

Proteomic characterization of oyster shell organic matrix proteins (OMP).

Oysters are economically and ecologically important bivalves, with its calcareous shell and delicious meat. The shell composition is a blend of inorganic crystals and shell proteins that form an organic matrix which protects the soft inner tissue of the oyster. The objective of the study was to compare the composition of organic matrix proteins (OMP) of two phylogenetically related species: the Hong Kong oyster (Crassostrea hongkongensis) and the Portuguese oyster (Crassostrea angulata) which differ in their shell hardness and mechanical properties. C. hongkongensis shells are comparatively stronger than C. angulata. Modern shotgun proteomics has been used to understand the nature of the OMP and the variations observed in the mechanical properties of these two species of oyster shells. After visualizing proteins on the one (1DE) and two-dimensional electrophoresis (2DE) gels, the protein spots and their intensities were compared using PDQuest software and 14 proteins of C. hongkongensis were found to be significantly different (student׳s t-test; p<0.05) when compared to the C. angulata. Furthermore, shell OMP separated on 1DE gels were processed using Triple TOF5600 mass spectrometry and 42 proteins of C. hongkongensis and 37 of C. angulata identified. A Circos based comparative analysis of the shell proteins of both oyster species were prepared against the shell proteome of other shell forming gastropods and molluscs to study the evolutionary conservation of OMP and their function. This comparative proteomics expanded our understating of the molecular mechanism behind the shells having different hardness and mechanical properties.

Gastropod shell utilisation pattern by the hermit crab Clibanarius symmetricus (Anomura: Diogenidae) in an Equatorial Amazon estuary

ABSTRACTClibanarius symmetricus is a diogenid hermit crab that is highly abundant in rocky intertidal environments, including the rock outcrops of Amazon estuaries. This study characterises the C. symmetricus shell utilisation pattern in the Marapanim River estuary, Pará, Equatorial Amazon, based on the hypothesis that occupancy patterns would differ, in relation to biometry and diversity of occupied shells, from those of other regions in the range of this species due to the distinct and unique environmental characteristics of equatorial estuaries. Monthly samplings were carried out from August 2006 to July 2007, in the upper and lower areas of the mid-littoral during low tides. A total of seven gastropod species were found as shells occupied by hermit crabs: 93.33% were Thaisella trinitatensis shells, 2.00% Nassarius vibex, 2.00% Neritina virginea, 1.33% Natica marochiensis, 0.67% Parvanachis obesa, and, occasionally, Littorina flava and Phalium granulatum shells, each with only one occurrence (0.33%). Juveniles [cephalothoracic shield length (CL) of less than 3.6 mm] occupied a higher variety of shells, while adults occupied shells with larger meristic variation. Males occupied larger shells. The length of the animal was influenced by shell measurements (total width, aperture width and weight). Clibanarius symmetricus showed occupancy patterns generally similar to those of specimens of the same species previously studied in the Brazilian subtropical region, and this occupancy is explained by shell availability, shell size and weight, and hermit size. However, this study showed lower occupied shell species diversity, and the species with highest occupancy frequency (T. trinitatensis) was not reported in any previous studies on this hermit crab. In addition, the studied population differed in occupancy patterns, with differences between males and females, and between juveniles and adults.

Electron spin resonance spectroscopy of empty and endohedral fullerenes

Fullerene derivatives exhibit many interesting structural, electronic, and chemical properties, largely determined by the carbon cage's ability to accept electrons. Electron spin resonance spectroscopy is a very sensitive and important technique to detect open shell species and to determine HOMO and LUMO density distributions. Here we present a short overview of the most significant and informative reports of electron spin resonance studies of empty and endohedral fullerenes, classified on the basis of the entrapped moiety, cage size symmetry, and on the techniques used to generate the paramagnetic states. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Deciphering Selectivity in Organic Reactions: A Multifaceted Problem.

Computational chemistry has made a sustained contribution to the understanding of chemical reactions. In earlier times, half a century ago, the goal was to distinguish allowed from forbidden reactions (e.g., Woodward-Hoffmann rules), that is, reactions with low or high to very high activation barriers. A great achievement of computational chemistry was also to contribute to the determination of structures with the bonus of proposing a rationalization (e.g., anomeric effect, isolobal analogy, Gillespie valence shell pair electron repulsion rules and counter examples, Wade-Mingos rules for molecular clusters). With the development of new methods and the constant increase in computing power, computational chemists move to more challenging problems, close to the daily concerns of the experimental chemists, in determining the factors that make a reaction both efficient and selective: a key issue in organic synthesis. For this purpose, experimental chemists use advanced synthetic and analytical techniques to which computational chemists added other ways of determining reaction pathways. The transition states and intermediates contributing to the transformation of reactants into the desired and undesired products can now be determined, including their geometries, energies, charges, spin densities, spectroscopy properties, etc. Such studies remain challenging due to the large number of chemical species commonly present in the reactive media whose role may have to be determined. Calculating chemical systems as they are in the experiment is not always possible, bringing its own share of complexity through the large number of atoms and the associated large number of conformers to consider. Modeling the chemical species with smaller systems is an alternative that historically led to artifacts. Another important topic is the choice of the computational method. While DFT is widely used, the vast diversity of functionals available is both an opportunity and a challenge. Though chemical knowledge helps, the relevant computational method is best chosen in conjunction with the nature of the experimental systems and many studies have been concerned with this topic. We will not address this aspect but give references in the text. Usually, a computational study starts with the validation of the method by means of benchmark calculations vs accurate experimental data or state-of-the-art calculations. Finally, computational chemists can bring more than the sole determination of the reaction pathways through the analysis of the electronic structure. In our case, we have privileged the NBO analysis, which has the advantage of describing interactions on the basis of terms and concepts that are shared within the chemical community. In this Account, we have chosen to select representative reactions from our own work to highlight the diversity of situations than can be addressed nowadays. These include selective activation of C(sp(3))-H bonds, selective reactions with low energy barriers, involving closed shell or radical species, the role of noncovalent interactions, and the importance of considering side reactions.

Systematic synthesis of polyimide@inorganics core-shell microspheres via ion-exchange and interfacial reaction

Uniform and stable core-shell microspheres composed of a polyimide (PI) core and thin metal/oxide/sulphide shells were prepared by an interfacial reaction of metal-ion-doped polymeric cores in reduction or in the air or sodium sulphide solutions, respectively. The silver shells on polyimide microspheres were prepared by the introduction of silver ions into ion-exchangeable surface-modified polyimide, and subsequently an in situ reduction of the silver ions in solution. Oxides shells such as SnO2, Co3O4, NiO, CuO or ZnO were prepared by thermally treating the ion-doped microspheres in air, while amorphous sulphides shells such as CuS, ZnS, CoS or Ag2S were prepared by an interfacial reaction of metal-ion-doped microspheres in its corresponding sodium sulphide solutions. The adhesion properties between the copper sulphide and PI substrates are demonstrated superior. This simple strategy is promising in the fabrication of a whole range of inorganic shells on polyimide microspheres, which may offer tailor-designed multi-functionalities based on the distinctive species of these inorganic shells.

A New Species of Cone Shell (Gastropoda: Conidae) from the Saharan Coast of Northwestern Africa

A new species of Lautoconus (Conidae: Puncticulinae) is described from the intertidal rocky environments of Dahkla Bay, central Western Sahara. The new species is most similar to L. guanche from the Canary Islands, but differs in having a stockier, more darkly-colored, and lowerspired shell. The new species, here named L. saharicus n. sp., is endemic to Dahkla Bay and the Dahkla area of Western Sahara, roughly 400 km south of the Canary Islands.

Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles.

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large extinction coefficients which can be tuned across the visible spectrum. Research into the plasmonic enhancement of optical transitions has become popular, due to the possibility of altering and in some cases improving photo-absorption or emission properties of nearby chromophores such as molecular dyes or quantum dots. The electric field of the plasmon can couple with the excitation dipole of a chromophore, perturbing the electronic states involved in the transition and leading to increased absorption and emission rates. These enhancements can also be negated at close distances by energy transfer mechanism, making the spatial arrangement of the two species critical. Ultimately, enhancement of light harvesting efficiency in plasmonic solar cells could lead to thinner and, therefore, lower cost devices. The development of hybrid core/shell particles could offer a solution to this issue. The addition of a dielectric spacer between a gold nanoparticles and a chromophore is the proposed method to control the exciton plasmon coupling strength and thereby balance losses with the plasmonic gains. A detailed procedure for the coating of gold nanoparticles with CdS and ZnS semiconductor shells is presented. The nanoparticles show high uniformity with size control in both the core gold particles and shell species allowing for a more accurate investigation into the plasmonic enhancement of external chromophores.

Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large extinction coefficients which can be tuned across the visible spectrum. Research into the plasmonic enhancement of optical transitions has become popular, due to the possibility of altering and in some cases improving photo-absorption or emission properties of nearby chromophores such as molecular dyes or quantum dots. The electric field of the plasmon can couple with the excitation dipole of a chromophore, perturbing the electronic states involved in the transition and leading to increased absorption and emission rates. These enhancements can also be negated at close distances by energy transfer mechanism, making the spatial arrangement of the two species critical. Ultimately, enhancement of light harvesting efficiency in plasmonic solar cells could lead to thinner and, therefore, lower cost devices. The development of hybrid core/shell particles could offer a solution to this issue. The addition of a dielectric spacer between a gold nanoparticles and a chromophore is the proposed method to control the exciton plasmon coupling strength and thereby balance losses with the plasmonic gains. A detailed procedure for the coating of gold nanoparticles with CdS and ZnS semiconductor shells is presented. The nanoparticles show high uniformity with size control in both the core gold particles and shell species allowing for a more accurate investigation into the plasmonic enhancement of external chromophores.