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Several analytical approaches have been developed for the determination of emerging pollutants (EPs), including pharmaceuticals and personal care products (PPCPs) in environmental matrices. This paper reviews the sample preparation and instrumental methods proposed in the last few years (2012–2018) to assess PPCPs in sewage sludge. Three main steps are examined: extraction, clean-up and analysis. Sample preparation is critical as target compounds are normally found at low concentrations in complex matrices. Most procedures include sewage sludge pretreatment mostly through ultrasound-assisted extraction (UAE) although other novel techniques such as QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) or MSPD (matrix solid-phase dispersion) have been also employed. In one report, no differences in extraction efficiency were detected among the most commonly used extraction techniques such as ultrasound, microwave and pressurized liquid. Clean-up usually involves a conventional method such as solid phase extraction (SPE). This step is needed to appreciably reduce matrix suppression, and is followed by an instrumental analysis using techniques of preference such as gas chromatography (GC) or liquid chromatography (LC), mostly coupled to mass spectrometry (MS). A fully automated on-line system that includes extraction, chromatographic separation, and mass spectrometry in one-stage is here presented as a novel way of determining PPCPs in sewage sludge. This review also discusses the advantages and limitations of the different techniques used. Miniaturizing analytical techniques and the use of novel solid and liquid phase materials are emerging as efficient options that fulfill the principles of so-called "green chemistry". Image 1 • A critical review on the determination of PPCPs in sewage sludge is presented. • Analytical methodologies are discussed involving extraction, clean-up and instrumental analysis. • UAE represents more than a half of the publications using extraction techniques. • LC-MS/MS is the analysis technique more used to determinate PPCPs in sludge. • Miniaturization and automation of analytical techniques is becoming a trend to analyze environmental. [ABSTRACT FROM AUTHOR]

Nanostructured films consisting of single Si nanoparticles (NPs) and Er3+ ions layers separated by nanometer-scale Al2O3 layers of controlled thickness have been prepared in order to tune the energy transfer between Si NPs and Er3+ ions. The amorphous Si NPs with an effective diameter of ∼4.5 nm are formed during growth and are able to sensitize the Er3+ ions efficiently with no postannealing treatments. The characteristic distance for energy transfer from Si NPs to Er3+ ions in Al2O3 is found to be in the 1 nm range. It is shown that in the nanostructured films, it is possible to achieve an optimized configuration in which almost all the Er3+ ions have the potential to be excited by the Si NPs. This result stresses the importance of controlling the dopant distribution at the nanoscale to achieve improved device performance. [ABSTRACT FROM AUTHOR]

Analysis of the optical properties of bulk Cu(In1-xGax)3Se5 mixed crystals synthesized from the elements as a function of the Ga content is presented. Measurements of the complex dielectric function [variant_greek_epsilon](ω)=[variant_greek_epsilon]1(ω)+i[variant_greek_epsilon]2(ω) were performed at room temperature in the photon energy range of 0.8–4.7 eV using a variable angle of incidence ellipsometer. The spectral dependence of the complex refractive index, the absorption coefficient, and the normal-incidence reflectivity were also derived. The structure observed in the dielectric functions attributed to the interband transitions E0, E1A, and E1B has been modeled using a modification of the Adachi’s model. The results are in excellent agreement with the experimental data over the entire range of photon energies. The model parameters, including the energies corresponding to the lowest direct gap and higher critical points, have been determined using the simulated annealing algorithm. The values of E0 and E1A are found to increase linearly with the increasing Ga content. [ABSTRACT FROM AUTHOR]

The complex dielectric functions, [variant_greek_epsilon](ω)=[variant_greek_epsilon]1(ω)+i[variant_greek_epsilon]2(ω), of CuIn3Se5 and CuIn5Se8 crystals with different Cu contents have been determined in the 0.8–4.7 eV photon energy range by using spectroscopic ellipsometry. The spectral dependence of the real, [variant_greek_epsilon]1(ω), and imaginary, [variant_greek_epsilon]2(ω), parts of [variant_greek_epsilon](ω), as well as the complex refractive index, the absorption coefficient, and the normal-incidence reflectivity, has been modeled by using a modification of Adachi’s model. The results are in excellent agreement with the experimental data over the entire range of photon energies. The model parameters, including the energies corresponding to the lowest direct gap, E0, and to higher critical points, have been determined by using the simulated annealing algorithm. [ABSTRACT FROM AUTHOR]

Spectral dependence of the real [variant_greek_epsilon]1(ω) and imaginary [variant_greek_epsilon]2(ω) parts of the complex dielectric function, complex refractive index, absorption coefficient, and normal-incidence reflectivity of CuGa5Se8 crystals with slightly different Cu contents are modeled using Adachi’s model for interband transitions. The results are in good agreement with the experimental data over the entire range of photon energies. The model parameters are determined using the simulated annealing algorithm. [ABSTRACT FROM AUTHOR]

Er–Tm codoped a-Al2O3 thin films prepared by alternate pulsed laser deposition show a broad photoluminescence band with two characteristic peaks at 1540 and at 1640 nm, respectively, related to Er3+ and Tm3+ emissions. Two series of films have been prepared. For the first series, the Tm concentration [Tm] has been increased while keeping constant the Er concentration [Er]. The results show that the photoluminescence intensity at 1640 nm (I1640) to that at 1540 nm (I1540) decreases and that at 1640 nm (I1640) increases, i.e., the (I1640/I1540) ratio increases as [Tm] is increased. For [Tm]/[Er]=3, a fairly flat emission spectrum (I1640/I1540∼1) with a full width at half maximum of 230 nm is achieved. For the second series both [Tm] and [Er] are increased while keeping the [Tm]/[Er] ratio constant. The I1640/I1540 ratio tends to be constant with a full width at half maximum of 150 nm. The lifetime values decrease in all cases as [Tm] increases. The evolution of the I1640/I1540 and lifetimes as a function of [Tm] as well as the analysis of the latter considering Er as a donor and Tm as an acceptor evidence that there is an efficient energy transfer from Er3+ to Tm3+. These results suggest that enhanced performance with a flat broadband emission useful for planar integrated devices is achievable by further dopant engineering in the nanoscale. [ABSTRACT FROM AUTHOR]

Spectral dependence of the pseudodielectric function [variant_greek_epsilon](E)=[variant_greek_epsilon]1(E)+i[variant_greek_epsilon]2(E) as well as of the complex refractive index, extinction coefficient, absorption coefficient, and normal-incidence reflectivity of Cu2In4Se7 and CuGa3Se5 ordered vacancy compound crystals are modeled in the 0.8–4.4 eV photon energy range using a modification of Adachi’s model [T. Kawashima et al. J. Appl. Phys. 84, 5202 (1998)] for optical properties of semiconductors. Model parameters are determined using the acceptance-probability-controlled simulated annealing method. Excellent agreement with experimental data is obtained; the relative errors for the real [variant_greek_epsilon]1 and for imaginary [variant_greek_epsilon]2 part of the dielectric function are equal to 0.9%–1.5% and 3.2%–4.1% for the studied compounds. [ABSTRACT FROM AUTHOR]

The dielectric function ε(ω) of polycrystalline bulk samples of the quaternary chalcopyrite semiconductors Ag1-xCuxInSe2 with x=0.0, 0.2, 0.4, 0.6, 0.8, 1.0 has been determined by spectroscopic ellipsometry in the energy range from 0.5 to 4.7 eV at room temperature. Accurate values of refractive indices n and extinction coefficients k representative of bulk materials are obtained from the data. The value of the main energy gap is very sensitive to the composition and varies from 1.225 to 1.009 eV as x increases (Cu content). The structures observed in ε(ω) have been analyzed by fitting the numerically differentiated experimental spectrum ssecond derivatived to analytical line shapes. As a result, the energies corresponding to different electronic transitions have been determined as a function of the composition, and they have been identified within the electronic band structure of chalcopyrites. [ABSTRACT FROM AUTHOR]

Nanocomposite thin films formed by Ag nanocrystals embedded in an amorphous aluminum oxide (Al[sub 2]O[sub 3]) host were prepared by alternating-target pulsed laser deposition. Spectroscopic ellipsometry was used to determine the effective refractive index (n=n+ik). When the Ag volume fraction is over 2%, the linear optical properties of the nanocomposite films differ from those of the pure dielectric host. The extinction coefficient shows a maximum around 435 nm that is related to the surface plasmon resonance. Near this wavelength, the real part of the refractive index undergoes anomalous dispersion, leading to a significant increase of the n value of the composite compared to that of the matrix. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Erbium doped Al[sub 2]O[sub 3] films with concentrations up to 6×10[sup 20] Er cm[sup -3] have been prepared in a single step process by pulsed-laser deposition. Alternate ablation of Al[sub 2]O[sub 3] and Er targets has been used to control the in-depth distribution and in-plane concentration of Er[sup 3+] ions independently. The characteristic Er[sup 3+] photoluminescence response at 1.53 μm has been studied as a function of the Er[sup 3+] distribution. It is found that lifetime values can be greatly increased by increasing the Er[sup 3+]–Er[sup 3+] in-depth separation above 3 nm. This result can be related to a reduced Er[sup 3+]–Er[sup 3+] energy migration process. The in-plane Er[sup 3+] concentration was increased by either increasing the number of pulses on the Er target or the laser energy density for ablation. By the latter method in-plane concentrations as high as 1.1×10[sup 14] Er cm[sup -2] per layer (corresponding to 2×10[sup 20] Er cm[sup -3]) were achieved, while keeping lifetime values as high as 6 ms. This result is explained in terms of shallow Er[sup 3+] implantation during deposition. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We demonstrate that optical extinction spectroscopy can be used to determine the effective shape of Cu nanocrystals (NCs) embedded in a transparent amorphous Al[sub 2]O[sub 3] host both produced by pulsed laser deposition. The axial ratio of the NCs was extracted from the positions of the surface plasmon modes of the optical extinction spectra of the nanocomposite film. Comparison to the results obtained by grazing incidence small angle x-ray scattering shows excellent agreement. Thus, optical spectroscopy can be used as a simple, easily accessible, and versatile tool for the characterization of the NCs that form nanocomposite films. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents a study reporting on the optical characterization by spectroscopic ellipsometry (SE), of composite films with Bi nanocrystals in Ge (Bi:Ge films) and Al2O3 (Bi:Al2O3 films) hosts produced by pulsed laser deposition (PLD) in vacuum. Methodology used to conduct the study; Details on Bi:Ge films; Findings of the study.

Provides information on a study that used of molecular beam epitaxy in the incorporation and optical activation of erbium in silicon to focus on the effect of oxygen on the erbium-related luminescence.

Presents a study which examined the crystallization kinetics of amorphous germanium films under nanosecond laser irradiation. Analysis of the presence of relaxation processes in the amorphous phase; Implications of real time reflectivity measurements and Raman spectroscopy for amorphous regrowth; Reflectivity transients obtained at increasing pulse energy densities.

Studies the room-temperature luminescence from erbium-implanted oxygen-doped silicon epitaxial films grown by molecular beam epitaxy. Purpose of the optical doping of silicon with erbium; Details on the experiment; Discussion on the results of the study.

Presents information pertaining to the production of the active rare-earth Er3+ -Yb3+ co-doped phosphate glass films using pulsed laser deposition in a single step. Description of the films; Reference to the density of the films obtained under the conditions of photoluminescence intensity; How luminescent emission can be excited.

Presents a study which analyzed the solid-liquid transition induced in antimony by laser irradiation by means of real time reflectivity measurements. Principle behind the real time reflectivity procedure; Materials and methods used; Results.

Materials, and particularly glasses, with a tailor-made spectral optical response that can be switched in a controlled way using external stimuli excitation are of interest for the development of active optical devices, such as active filters or all-optical switching components. Based on the dielectric functions of solid and liquid bismuth (Bi), it is expected that both solid and liquid Bi nanostructures will show optical resonances with relevant different features in the near ultraviolet to near infrared. In addition, Bi has a low melting point that enables the solid–liquid phase change under moderate heating. Profiting of these singular properties we present and review in this paper the main results that have been obtained in our laboratory concerning the thermo-optical response of bulk germanate glasses and amorphous Al 2 O 3 thin films with embedded Bi nanoparticles (NPs). In both materials the optical transmission as a function of the temperature shows broad hysteresis loops. The optical contrast and width of these cycles depend on the Bi content and NP size. From the successful modelling of the optical properties of the Bi NPs-doped glasses, it is proposed that the observed material thermo-optical response arises from the change in the dielectric function of the Bi NPs upon melting, which induces relevant changes in the resonant optical behaviour of the Bi NPs. These results suggest that glasses with embedded Bi NPs are promising for the design of spectral-selective thermo-optical devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • A comparison of three different analytical proposals for the analysis of PPCPs in sewage sludge was presented. • A clean-up step was essentially preceded by the extraction technique UAE. • A direct injection of the UAE extract with no prior clean-up in LC-MS/MS provided the best performance. • The resulting analytical method was validated and successfully applied in dewatered digested sludge samples. • Acetaminophen reported concentrations above 1,000 ng g−1. This paper presents a comparison of three different analytical proposals for the determination of 60 pharmaceuticals and personal care products (PPCPs) in solid urban sewage sludge. Two fast sample pretreatments, i.e., online solid-phase-extraction (online SPE) and direct injection (DI), were tested against the conventional offline solid phase extraction (offline SPE). In all cases, subsequently, extracts underwent ultra-high-performance-liquid chromatography coupled to tandem-mass-spectrometry (UHPLC-MS/MS), simultaneously operating in both positive and negative electrospray ionization (ESI) mode. In addition, as solid matrices, clean-up steps were necessarily preceded by ultra-sound-assisted extraction (UAE) in all cases. Matrix-matched quantification was combined with internal standard providing high reliability to all three approaches. Best performance was observed for the fully automatized and non-pretreated DI method, showing limits of detection below 30 ng g−1 for many of the target compounds, and recoveries between 80 and 120%. Finally, the best working method was validated and applied to the analysis of PPCPs in different dewatered digested sludge samples from the wastewater treatment plant (WWTP) in Valladolid (Spain). Acetaminophen was found at concentrations above 1,000 ng g−1. [ABSTRACT FROM AUTHOR]

This work shows the influence of conditioning the Bi target previous to the pulsed laser deposition of Bi nanocomposite films on their optical and thermo-optical properties. The nanostructured films prepared by alternate pulsed laser deposition at room temperature in vacuum consist of Bi nanostructures (NSs) with different characteristic sizes that are organized in layers and embedded in an amorphous AlO host. Preablation of the Bi target prior to deposition leads to higher Bi concentration and Bi NSs with larger average sizes. As a result a lower optical transmission and an enhanced thermo-optical contrast are observed. [ABSTRACT FROM AUTHOR]

Abstract: Alternate pulsed laser deposition from the host (Al2O3) and dopant (Er, Yb) targets has been used to prepare artificially nanostructured films in which the rare earth ion–ion separation is controlled in the nanometer scale in order to control energy transfer between ions. One series of films was prepared in the standard on-axis configuration, i.e. a static substrate being centred with respect to the plasma expansion axis. A second series of films was prepared by rotating the substrate with respect to a shifted axis parallel to the plasma expansion one (off-axis configuration). The latter configuration leads to films with enhanced thickness and Er related photoluminescence intensity uniformity. More interestingly, the Er related photoluminescence lifetime in as-grown films increases up to 2.5ms, which is much higher than the maximum value of 1ms obtained for the on-axis configuration films. This enhancement is discussed in terms of a decrease of defect density when using the off-axis configuration. [Copyright &y& Elsevier]

The near-infrared emission from calcium boroaluminate (CABAL) glasses codoped with Er3+ and Tm3+ has been investigated. It is shown that by controlling the [Tm]/[Er] concentration ratio a fairly flat emission with a bandwidth of 370 nm can be achieved in the wavelength range from 1.4 to 2.0 μm. The broadband emission is formed by three bands centered at 1.4, 1.5 and 1.8 μm, which are related to the emission from the Tm3+: 3 H4→3 F4, Er3+: 4 I13/2→4 I15/2 and Tm3+: 3 F4→3 H6 transitions, respectively. Compared to Er-only doping and Tm-only doping at the same concentration, codoping with both ions leads to a reduction of the intensity and lifetime of the Er-related band at 1.53 μm and to an intensity enhancement of the two Tm-related emission bands at 1.46 and 1.80 μm. This is a result of energy transfer (ET) processes between Er3+ and Tm3+ ions that are relevant when determining the emission spectrum shape. Two dominant ET processes are identified, both consisting of transferring the energy of the Er3+ first excited level (4 I13/2) in the first case to the Tm3+ first excited level (3 F4), which is excited to the third excited level (3 H4), and in the second case to the Tm3+ ground state (3 H6) which is excited to the first excited level (3 F4). [ABSTRACT FROM AUTHOR]

Abstract: The role played by the laser fluence on the Al2O3 target when depositing VO x :Al2O3 nanocomposite thin films by alternate ablation from ceramic alumina (Al2O3) and metallic vanadium (V) targets in vacuum has been studied. The fluence and number of pulses on the V target to prepare the nanoparticles has been maintained constant, while the fluence used to grow the Al2O3 host has been varied from 1.3 to 3.9Jcm−2. The optical properties of the films, namely in-situ reflectivity during growth and extinction coefficient, evidence that the properties of the nanoparticles change as a function of the laser fluence on the Al2O3 host. Transmission electron microscopy analysis shows the formation of vanadium oxide nanoparticles with average diameters in the range of 4.6nm. Structural analysis of the nanoparticles shows that they are mainly crystalline. Phases of VO x with average [O]/[V] ratios from 1.7 to 2.2 have been identified with the most commonly observed being V3O5. This is in agreement with low heat of formation of this oxide. It is shown that the oxidation of the nanoparticles induced during the deposition of Al2O3 is very efficient since no metallic V nanoparticles are formed even for the lowest fluence used. [Copyright &y& Elsevier]

Abstract: The formation and optical response of VO x nanoparticles embedded in amorphous aluminium oxide (Al2O3) thin films by pulsed laser deposition is studied. The thin films have been grown by alternate laser ablation of V and Al2O3 targets, which has resulted in a multilayer structure with embedded nanoparticles. The V content has been varied by changing the number of pulses on the V target. It is found that VO x nanoparticles with dimensions around 5nm have been formed. The structural analysis shows that the vanadium nanoparticles are oxidized, although probably there is not a unique oxide phase for each sample. The films show a different optical response depending on their vanadium content. Optical switching as a function of temperature has been observed for the two films with the highest vanadium content, at transition temperatures of about −20°C and 315°C thus suggesting the presence of nanoparticles with compositions V4O7 and V2O5, respectively. [Copyright &y& Elsevier]

Abstract: Amorphous Al2O3 films doped with Er, Tm and Yb have been prepared by pulsed laser deposition. A broadband emission in the range 1400–1700nm with two peaks around 1540 and 1640nm has been observed, both in the Er-Tm and Er-Tm-Yb codoped films. The Tm-related photoluminescence (PL) intensity at 1640nm is enhanced when codoping with Yb thus suggesting the existence of multiple energy transfer processes from Yb to Er and Er to Tm. The Er–Tm–Yb codoped film exhibits a broadband emission with a full-width half-maximum of 184nm similar to that of the film codoped with Tm and Er but having higher Tm to Er concentration ratio and higher PL lifetime values. [Copyright &y& Elsevier]

Landraces and bean (Phaseolus vulgaris L.) cultivars grown in Mexico are diverse, as are consumer preferences and agroecological production environments. Mexican common bean cultivars were analyzed using amplified fragment length polymorphism (AFLP) finger-printing to examine the genetic relationships within and among races, based on the genotyping of 112 bred cultivars developed in Mexico. Molecular analysis of dry bean germplasm will be useful to corroborate previous cultivar characterizations and establish the genetic basis of improved germplasm, to facilitate the use of that diversity, and to implement the use of markers in selection. Germplasm included 111 cultivars belonging to Mesoamerica (25), Jalisco (39), Durango (28), and Nueva Granada (19) races, which are commonly cultivated throughout the bean-producing areas of Mexico. A Mexican P. coccineus species cultivar (Blanco Tlaxcala) was also included for comparison. Broad genetic diversity was found within bean races, and diversity values between races were similar. Most of the Nueva Granada germplasm was clearly different from that of alt other races, whereas the P. coccineus cultivar was distinct from all P. vulgaris cultivars. A based on the AFLP analysis did not clearly match with that made on the basis of racial classification. This mismatch was probably due to genetic recombination between Andean (Nueva Granada) and Mesoamerican (Jalisco, Durango, and Mesoamerica) gene pools. Utilization of contrasting parents for specific crosses has also contributed to broadening the genetic basis of common bean. [ABSTRACT FROM AUTHOR]

Abstract: Pulsed laser deposition has been used to prepare nanostructured rare-earth-doped films. Alternate deposition from the host (Al2O3) and dopant (Er, Yb) targets has been used to obtain artificially structured films in which the rare-earth ion–ion separation is controlled in the nanometer scale (0.5–9nm). In the case of Er3+–Er3+ interactions, it has been found that self-quenching is greatly reduced for separations larger than 3nm. The control of the laser fluence used for Er ablation is also important, and higher fluences lead to higher luminescence efficiencies. The Er and Yb co-doped films have been designed with the Er3+ and Yb3+ ions distributed either in the same layer or in different layers separated from 1 to 3nm. The emission intensity in these co-doped films can be up to two orders of magnitude higher than that reported for films doped only with Er. The results evidence that structuring the rare-earth distribution in the nanometer scale is a very efficient means to reduce rare-earth clustering. Finally, it will also be shown that nanostructuring offers a valuable method to analyze ion–ion interactions such as energy transfer mechanisms. [Copyright &y& Elsevier]

The synthesis by pulsed laser deposition of a bismuth nano-plane embedded in an amorphous germanium matrix is reported. The structural changes were studied by Raman spectroscopy as a function of temperature. Upon heating, the Bi nano-plane melts and, as the sample is cooled, it re-crystallizes at a temperature well below the melting point. The results show a broad melting–solidification hysteresis cycle (170 K) that is compared to the ones obtained earlier on nanoparticles. Furthermore, a metal-induced crystallization effect was also observed in the germanium matrix. [ABSTRACT FROM AUTHOR]

Thin films of Zn have been prepared by pulsed laser deposition with a KrF excimer laser (248 nm). The laser energy density (E.D.) on the target has been varied in the 1 to 5 J/cm2 range. The results show that as the E.D. increases the material distribution changes. For low E.D.(≤ 1.6 J/cm2) the maximum of the distribution is at the substrate center, for intermediate E.D. it is displaced to the side, and a clear minimum appears at the center of the substrate for the higher E.D. (≥4.5 J/cm2). The growth velocity at the center of the substrate reaches a maximum value for E.D. of 2.8 J/cm2, and decreases for higher E.D. as a result of the competition between deposition and self-sputtering. Virtually a zero growth velocity is obtained for E.D. above 4.5 J/cm2. The self-sputtering process is most likely responsible for the increase of the film surface roughness as a function of the laser E.D. The low cohesive energy for metal Zn, compared to other metals (Fe, Ag, Cu) is correlated with the high efficiency of the self-sputtering for this material. [ABSTRACT FROM AUTHOR]

Structural properties as a function of temperature of bismuth nanocrystals embedded in amorphous germanium thin films, synthesised by laser ablation are investigated by Raman spectroscopy and X-ray diffraction. In addition to temperature anharmonic effects, Raman spectroscopy results reveal a melting solidification hysteresis, which takes place below the melting point of bulk bismuth. Furthermore, preliminary X-ray diffraction results suggest that the nanocrystals change in structure upon heating until melting occurs. However, the nanocrystals recover their original structure once the sample is cooled at room temperature. [Copyright &y& Elsevier]

Nanocomposite thin films formed by Cu nanocrystals (NCs) embedded in an amorphous aluminium oxide (Al[sub 2] O[sub 3] ) host have been prepared by alternate pulsed laser deposition. Spectroscopic ellipsometry is used to determine the effective refractive index (n=n+ik). The extinction coefficient is non-negligible and shows a broad absorption band related to the surface plasmon resonance. In the neighbourhood of this wavelength, the real part of the refractive index undergoes an anomalous dispersion, leading to a significant increase of the n value of the composite compared to that of the host. When the Cu content is low enough, about 2 at. %, the use of an effective medium approach combined with a regression method allows us to determine the metal content and film thickness from the ellipsometric measurements. For larger concentrations this approach is no longer valid. [ABSTRACT FROM AUTHOR]

Pulsed laser deposition in vacuum has been used to develop metal-oxide nanocomposite films with well controlled structural quality. Results for the copper—aluminium oxide (Cu:Al[sub 2]O[sub 3]) system are used to illustrate the main morphological and structural features of these films. High resolution transmission electron microscopy (TEM) analysis shows that the films consist of Cu nanocrystals with average dimensions that can be controlled between 2 nm and 10 nm embedded in an amorphous Al[sub 2]O[sub 3] matrix. It is observed that the in-plane shape of the nanocrystals evolves from circular to elongated, and the number of nanocrystals per unit area decreases as their size increases. This evolution is explained in terms of nucleation at the substrate surface and coalescence during the later stages of growth. The thermal stability of the films has been studied by in situ TEM annealing and no transformation could be observed up to about 800 °C when partial crystallization of the Al[sub 2]O[sub 3] starts. [ABSTRACT FROM AUTHOR]

Abstract. The processes leading to the formation of Cu:Al[sub 2]O[sub 3] composite films on Si (001) with a well defined nanostructure by alternate pulsed laser deposition (a-PLD) in vacuum are investigated. Alternately amorphous Al[sub 2]O[sub 3] layers and Cu nanocrystals nucleated on the Al[sub 2]O[sub 3] surface are formed, according to the PLD sequence. The Al[sub 2]O[sub 3] deposited on the Cu nanocrystals fills in the space between them until they are completely buried, and subsequently, a continuous dense layer with a very fiat surface (within 1 nm) is developed. The nucleation process of the nanocrystals and their resulting oblate ellipsoidal shape are discussed in terms of the role of the energetic species involved in the PLD process and the metal-oxide interface energy. [ABSTRACT FROM AUTHOR]

Abstract. Bi nanoclusters embedded in an amorphous Ge matrix have been produced by alternate pulsed laser deposition in a vacuum. The resulting thin films have been analyzed by high resolution electron microscopy, and the images show that the Ge matrix is amorphous and that Bi nanocrystals are formed. The size of the nanoclusters was easily changed within the range 2 nm to 25 nm by varying the number of pulses on the Bi target. Both the dependence of the nanocrystal size on the number of laser pulses on the Bi target and the results of tilting experiments in the electron microscope show that the nanocrystals have an oblate ellipsoidal shape with a much shorter axis in the direction of the film normal. This particular shape is related to their growth mechanism after nucleation at the substrate. [ABSTRACT FROM AUTHOR]

This work describes the design, optimization and validation of an analytical method for the simultaneous determination of 14 pharmaceuticals and personal care products (PPCPs) in sewage sludge. A thorough optimization of the sample pre-treatment was carried out. As a result, microwave-assisted extraction (MAE) was combined with an in-situ clean-up stage and a filtration step. A combination of MilliQ® water/MeOH 95:5 (v/v) adjusted to pH 9 turned out to be the optimal solvent mixture for extraction. The instrumental part of the method presents a significant novelty based on a fully automated sample preparation for the analysis of PPCPs. It consisted of a direct immersion solid phase microextraction followed by on-fiber derivatization, online coupled to gas chromatography - mass spectrometry (DI-SPME-On-fiber derivatization - GC-MS). An isotope dilution approach was used for quantifying, which conferred high reliability to the method. This methodology was validated for 10 compounds with good analytical performance, limit of detection below 20 ng g−1 and absolute recovery in the range of 30–70% for most of the compounds. It supposes an ecological analytical alternative for many routine analysis laboratories around the world. The developed method was applied to different real samples generated in both a pilot-scale thermal hydrolysis treatment plant and an anaerobic digester operated in mesophilic conditions. Salicylic acid and naproxen were found at concentrations above 1000 ng g−1. Image 1 • A method for the determination of PPCPs in sewage sludge was optimized and validated. • Microwave-assisted extraction combined with in-situ clean-up and filtration were presented. • Online-DI-SPME-On-Fiber-Derivatization-GC-MS was used for analysis of PPCPs in sludge samples. • The analytical method was successfully applied to different real samples. • PPCPs were detected in concentration between 48 and 9355 ng g−1. [ABSTRACT FROM AUTHOR]

Abstract: This work reports optical transmission changes in layered Bi nanostructures (NSs) upon heating–cooling cycles up to temperatures above the melting temperature. The nanostructured films prepared by pulsed laser deposition consist of Bi NSs with different characteristic sizes that are organised in layers and embedded in an amorphous Al2O3 host. The spectral dependence of the optical transmission as well as its changes upon heating are reported. The combination of Bi NSs layers with more than one characteristic size allows controlling the width of the melting–solidification transition. Eventually, it is shown how a multiple temperature thermo-optical film can be designed and prepared. [Copyright &y& Elsevier]

Thin films of amorphous aluminum oxide (Al2O3) co-doped with Er3+ and Tm3+ have been synthesized by alternate pulsed laser deposition. When pumped at 794 nm a broad emission band over 1400–1700 nm is observed. Two peaks related to the 1540 nm band from Er3+ and to the 1640 nm band from Tm3+ are clearly distinguished. The photoluminescence intensity ratio of the 1640–1540 nm emissions has been controlled by modifying the Tm concentration. A spectrum with a fairly flat profile and a full width at half maximum of 230 nm is obtained for an Er concentration of 7.2×1019 cm-3 and a [Tm]/[Er] concentration ratio of 3. It is found that the Er3+ to Tm3+ energy transfer processes play an important role in the definition of the luminescent response. The large width of the emission band and the excellent optical and thermomechanical properties of the Er–Tm co-doped Al2O3 signal this system as a potential candidate for the development of broadband integrated optical amplifiers. [ABSTRACT FROM AUTHOR]

Thin films of amorphous aluminum oxide (a-Al[sub 2]O[sub 3]) codoped with Er[sup 3+] and Yb[sup 3+] ions have been in-depth nanostructured by distributing the rate earth (RE) ions in layers separated in the 0–3 nm range. The Yb to Er concentration ratio is varied from 0 to 3.6. The photoluminescence (PL) response at 1.53 μm exhibits an increase of up to two orders of magnitude with respect to that of films doped only with Er. The PL intensity is improved when Yb[sup 3+] and Er[sup 3+] ions are in separate layers and the results show that efficient Yb[sup 3+] to Er[sup 3+] energy transfer can be achieved for separations up to 3 nm. Furthermore, it is shown that designing an adequate RE distribution, for the same total RE content and Yb to Er concentration ratio, can enhance the PL intensity by a further factor of two. It is shown that the Er[sup 3+] PL response is improved because of a reduction of the RE clustering and an improvement of the energy transfer from Yb[sup 3+] to Er[sup 3+] ions. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The refractive index of nanometric (<100 nm) chlorinated-silicon nitride films with embedded silicon quantum dots, prepared by remote plasma enhanced chemical vapor deposition was investigated by spectroscopic ellipsometry. The complex refractive indexes and thicknesses of the films were obtained from the ellipsometric measurements using the Cauchy model. The chemical composition of the bulk of the films, including the hydrogen, chlorine, and oxygen content, was measured by elastic forward analysis (EFA) and X-ray photoelectron spectroscopy (XPS). The EFA and XPS results indicate that the films are composed of nearly stoichiometric silicon nitride (Si3N4) with different amounts of hydrogen, chlorine, and oxygen, and that their top surface is oxidized. Based on the composition results the refractive index of the films was fitted using the effective medium approximation considering the system: Si substrate+Si3N4+Si+voids+top ultrathin oxidized surface layer. [ABSTRACT FROM AUTHOR]

Describes how erbium (Er)-doped aluminum oxide films have been deposited in a single-step process by pulsed laser deposition using independent ablation of aluminum oxide and Er targets. Control of the Er[sup 3+] ions in-depth distribution; Characteristic Er[sup 3+] photoluminescence at 1.54 micrometer.

Presents the thin films comprising of metal copper nanocrystals embedded in an aluminum oxide matrix by pulsed laser deposition. Preparation of the films in vacuum on glass substrates at room temperature; Thickness and nanocrystal contents of the material; Third-order susceptibility and electronic nonlinear refractive index of the films.

Thin Al2O3 films are grown and in situ doped with erbium by pulsed laser deposition in a single step process, by alternate ablation from Al2O3 and Er targets. The as-deposited films have an Er step dopant profile throughout the film thickness, whose concentration depends on the number of pulses at the Er target. The as-grown films are optically active, as evidenced by the photoluminescence spectrum centered at 1.533 μm, corresponding to intra-4f transitions in Er3+. The photoluminescence intensity increases upon annealing due to an increase of the luminescence lifetime. This is most likely a result of a decrease in the nonradiative decay channels, related to annealing of defects in the Al2O3 film. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Evaluates the growth of heteroepitaxial Si[sub 0.8]Ge[sub 0.2] thick films on silicon(100) by an all-laser assisted technique. Application of pulsed laser deposition technique; Use of argon fluoride excimer laser; Induction of melting and rapid solidification.

Presents a photoluminescence characterization of hydrogenated amorphous silicon doped with erbium by ion implantation. Temperature range used in thermal annealing; Mediation of erbium cations by photocarriers; Luminescence quenching factor in oxygen codoping.

Examines the luminescence quenching in erbium-doped hydrogenated amorphous silicon. Observation of the room-temperature photoluminescence after thermal annealing; Effect of oxygen codoping on the luminescence quenching; Correlation between quenching and the decrease of luminescence intensity.

Investigates the segregation and trapping of erbium during silicon (100) molecular beam epitaxy. Formation of silicide precipitates; Result of growing silicon in a certain oxygen background pressure; Absence of erbium segregation on silicon (111).

Melt-quenched borosilicate glasses, co-doped with Bi and V ions, exhibited broad visible spectrum emissions. Bi ions primarily existed as Bi3+, acting as network modifiers, lowering the glass transition temperature linearly with increasing Bi content. V5+ ions adopted tetrahedral coordination as [VO 4 ]3- units. Photoluminescence of Bi ions is shifted from blue to longer wavelengths with higher Bi content, associated with the stabilization of Bi2+ and the presence of Bi3+ in different local environments. Combined with V ions, the glasses emitted light covering the entire visible spectrum, offering the potential for white LED applications with correlated color temperatures ranging from 6135 to 4010 K. The highest QY was 11.9 and 8.0 % upon excitation at 325 and 340 nm. [ABSTRACT FROM AUTHOR]

The dielectric functions of Cu2ZnGeS4 bulk crystals grown by the Bridgman method were measured over the energy range 1.4 to 4.7 eV at room temperature using variable angle spectroscopic ellipsometry. The observed structures in the dielectric functions were adjusted using the Adachi's model and attributed to interband transitions E0, E1A, and E1B at Γ:(000), N(A):2π/a(0.5 0.5 0.5), and T(Z):2π/a(0 0 0.5) points of the first Brillouin zone, respectively. The model parameters (threshold energy, strength, and broadening) have been determined using the simulated annealing algorithm. The decrease in the first gap, E0, has been attributed to a higher Ge-S hybridization. The spectral dependence of the complex refractive index, the absorption coefficient, and the normal-incidence reflectivity were also derived. [ABSTRACT FROM AUTHOR]

The optical performance of europium (Eu) doped SiAlON thin films and its preparation by pulsed laser deposition are studied. The undoped SiAlON films show a high refractive index (2.34) close to that of silicon nitride. After doping with Eu the oxygen content increases in the films and leads to the formation of an oxynitride with a refractive index of 1.87 and excellent transparency in the visible-near infrared. Upon excitation at 355 nm the films show a broad band (FWHM of 200 nm) emission in the visible range (400–750 nm) that is associated to the emission of the Eu in the 2+ oxidation state. Enhancement of the emission together with a blue spectral shift has been found when the films are annealed at low temperature (600 °C). These films show promising properties for the development of Si compatible thin films integrated emitters. [ABSTRACT FROM AUTHOR]

ZnO is a semiconductor with a great interest, but it has several deficiencies which limit its use in technologic applications. One important limitation is having the band gap in the UV which reduces its use in optical devices. To solve this problem, in this work, composites based in ZnO with goethite and graphene oxide (GO) by sol-gel are prepared. The obtained samples (powders and thin films) were characterized microstructurally (DTA, XRD, micro-Raman, FE-SEM), optically (transmittance and photoluminescence) and magnetically (SQUID). The ZnO band gap of multifunctional composites shows a red-shift towards visible range (E g ∼3.01 eV) with high transmittance ∼85% (thickness of 362 nm) over the visible wavelength range. A long-range magnetic order at room temperature appears in these nanocomposites (Ms = 1.60·10 −2 emu/g). The combination of both dopants allows modifying the functional properties of ZnO, opening a great field of applications in ZnO composites, such as spintronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]