Search

Summary Although it still contributes to less than 2% of the worldwide electricity generation, photovoltaics (PVs) is on the way to becoming a key energy technology for a global future renewable energy infrastructure. We present projections of worldwide CO2 emissions of the future PV industry, finding that these emissions will likely surpass those caused by the global shipping or aviation sector. As an alternative, we propose a fully printed PV reverse manufacturing concept that minimizes the carbon footprint to the ultimate lower limit of the glass substrate fabrication. This so called “in situ” approach is based on a perovskite absorber that is highly durable and encapsulated with glass solder between float glass substrates, reducing the CO2-footprint of conventional PV modules by 1/20th. Yielding a certified stabilized efficiency of 9.3%, this record efficiency for glass-solder-encapsulated perovskite PV paves the way for future solar cells with the lowest carbon footprints.

This paper introduces the successful implementation of a fibre-optic sensing system for direct and distributed strain measurement within the shotcrete lining of a conventional tunnel drive. The shotcrete lining of the top-heading and the invert are equipped with two layers (rock side and cavity side) of fibre-optic sensing cables installed in circumferential and longitudinal direction. All cables are measured autonomously for several weeks to capture the strain evolution inside the lining from the day of the construction to a posterior, well-hardened state. An additional follow-up measurement is conducted 2 months afterwards. The measurements enable an assessment of the strain distribution inside the lining with a spatial resolution in the range of some centimetres and a measurement resolution of up to 1 µm/m. Besides the conventional monitoring targets used for displacement recordings, measurement equipment like strain gages and pressure cells are also installed in the cross-section under investigation. Back-calculated strain from absolute displacements and the readings from the strain gages show good agreement with the results of the conducted fibre-optic measurements and verify the suitability of the used system.

Tremendous efforts have been dedicated toward minimizing the open-circuit voltage deficits on perovskite solar cells (PSCs), and the fill factors are still relatively low. This hinders their further application in large scalable modules. Herein, we employ a newly designed ammonium salt, cyclohexylethylammonium iodide (CEAI), for interfacial engineering between the perovskite and hole-transporting layer (HTL), which enhanced the fill factor to 82.6% and consequent PCE of 23.57% on the target device. This can be associated with a reduction of the trap-assisted recombination rate at the 3D perovskite surface, via formation of a 2D perovskite interlayer. Remarkably, the property of the 2D perovskite interlayer along with the cyclohexylethyl group introduced by CEAI treatment also determines a pronounced enhancement in the surface hydrophobicity, leading to an outstanding stability of over 96% remaining efficiency of the passivated devices under maximum power point tracking with one sun illumination under N-2 atmosphere at room temperature after 1500 h.

The electrically insulating space layer takes a fundamental role in monolithic carbon-graphite based perovskite solar cells (PSCs) and it has been established to prevent the charge recombination of electrons at the mp-TiO2/carbon-graphite (CG) interface. Thick 1 μm printed layers are commonly used for this purpose in the established triple-mesoscopic structures to avoid ohmic shunts and to achieve a high open circuit voltage. In this work, we have developed a reproducible large-area procedure to replace this thick space layer with an ultra-thin dense 40 nm sputtered Al2O3 which acts as a highly electrically insulating layer preventing ohmic shunts. Herewith, transport limitations related so far to the hole diffusion path length inside the thick mesoporous space layer have been omitted by concept. This will pave the way toward the development of next generation double-mesoscopic carbon-graphite-based PSCs with highest efficiencies. Scanning electron microscope, energy dispersive X-ray analysis, and atomic force microscopy measurements show the presence of a fully oxidized sputtered Al2O3 layer forming a pseudo-porous covering of the underlying mesoporous layer. The thickness has been finely tuned to achieve both electrical isolation and optimal infiltration of the perovskite solution allowing full percolation and crystallization. Photo voltage decay, light-dependent, and time-dependent photoluminescence measurements showed that the optimal 40 nm thick Al2O3 not only prevents ohmic shunts but also efficiently reduces the charge recombination at the mp-TiO2/CG interface and, at the same time, allows efficient hole diffusion through the perovskite crystals embedded in its pseudo-pores. Thus, a stable V OC of 1 V using CH3NH3PbI3 perovskite has been achieved under full sun AM 1.5 G with a stabilized device performance of 12.1%.

This work addresses the alignment of a light spot onto photovoltaic laser power converters for power-by-light applications. A model to compare the alignment tolerances of different cell designs by means of the maximum acceptable misalignment is introduced. Monolithic interconnected multi-segment cells, which are commonly used as high-voltage devices, suffer from poor current matching for misaligned light spots. We show that the maximum acceptable misalignment of circular pie-shaped high-voltage devices decreases quickly with increasing number of series connected segments. A lower limit for the precision of the alignment procedure is only 5.1% of the cell radius. This precision requirement is three times higher than for single-segment cells (15.7%).

Photovoltaics (PV) is on the way to become a global key energy technology. As PV is replacing fossil fuel based technology, it contributes to reduce the global CO2-emissions. However, it should be kept in mind that the fabrication of PV modules is connected with CO2 emission. To fulfil the Paris climate goals, the global PV industry needs to grow in such a way that it will have a significant share in global carbon emissions. Research-driven approaches to reduce the carbon footprint of PV have strong impact on this development. We identify the glass substrate and encapsulation as the ultimate lower boundary for carbon footprint for long-term stable grid connected PV technologies. By the in-situ concept for perovskite solar cells we introduce a holistic design approach guided by this lower limit for photovoltaic modules with a low carbon footprint of only 5% of current silicon PV. The feasibility of this idea is demonstrated by the fabrication of an efficient pre-encapsulated perovskite in-situ cell. The device shows record efficiencies of certified, stabilized 9.3 %. This is the highest reported efficiency of such solar cells with lowest carbon footprint.

The United Nations Sustainable Development Goals (SDGs) and their interactions in developing countries in general, and in Egypt specifically, form the basis of our review. Issues of energy and water supply, linked to agriculture in rural areas, combine several of the SDGs. The current status and the challenges for solar photovoltaic (PV) electricity production and water supply technologies in rural areas are critically described and an outlook on future developments is provided. The framework of the water–energy–food nexus approach and its relation to the SDGs globally in the MENA region and in Egypt is presented and recommendations are given on institutional governance and research and development to overcome the silo mentality and enhance sector collaboration on all levels as prerequisite to achieving the SDGs. The latest technical developments in PV and water technologies and their opportunities for rural development are outlined. Combined technical solutions are highlighted with examples from Egypt. Specifically, installed systems in various rural locations are presented, and their advantages and shortcomings are discussed. The review provides a context for the studies presented in the Special Section on Solar Energy Solutions for Electricity and Water Supply in Rural Areas, Journal of Photonics for Energy , Volume 9, Issue 4.

Single junction photovoltaic devices composed of direct bandgap III-V semiconductors such as GaAs can exploit the effects of photon recycling to achieve record-high open circuit voltages. Modeling such devices yields insight into the design and material criteria required to achieve high efficiencies. For a GaAs cell to reach 28 % efficiency without a substrate, the Shockley-Read-Hall (SRH) lifetimes of the electrons and holes must be longer than 3 s and 100 ns respectively in a 2 μm thin active region coupled to a very high reflective (>99%) rear-side mirror. The model is generalized to account for luminescence coupling in tandem devices, which yields direct insight into the top cell’s non-radiative lifetimes. A heavily current mismatched GaAs/GaAs tandem device is simulated and measured experimentally as a function of concentration between 3 and 100 suns. The luminescence coupling increases from 14 % to 33 % experimentally, whereas the model requires an increasing SRH lifetime for both electrons and holes to explain these experimental results. However, intermediate absorbing GaAs layers between the two sub-cells may also increasingly contribute to the luminescence coupling as a function of concentration.

An elegant solution for the power supply of sensor electronics is the application of power-by-light technology. With this technology several challenges related to conventional copper wiring are inherently overcome; benefits are galvanic isolation, the suppression of electromagnetic interference, and the possibility to combine power and bidirectional data transmission in a single fiber link. In order to power sensor electronics efficiently, a supply voltage in the range 3 to 12 V is typically required. This paper deals with the photovoltaic laser power converter used to convert the transmitted optical power back into electricity. The advanced cell concepts of multi-junction and multi-segment cells are discussed which both aim at an increased output voltage on the device level, thereby eliminating the need for additional DC/DC conversion. Modeling and experimental results of GaAs based cells are presented, namely of single-junction 2- to 12-segment cells as well as of a dualjunction single-segment structure. A discussion of the pros and cons of the different concepts is given, focusing on the consequences of misalignment and temperature changes.

Objectives: Intracranial infections due to multidrug- resistant (MDR) gram-negative pathogens are associated with increased morbidity and mortality. As therapeutic options are limited and systemic drug penetration into the infection focus is difficult, intraventricular therapy has been described. Methods: We report on a patient with intracranial abscess caused by MDR Acinetobacter baumannii. Results: He was treated with high doses of intravenous and intraventricular colistin resulting in microbiological clearance and clinical cure. Therapy was controlled by therapeutic drug monitoring (TDM) of serum and liquor colistin levels. About 100 cases with intraventricular or intrathecal colistin are reported in literature but data on TDM are sparse. Conclusions: This is one of the first cases providing data on TDM for locally administered high dose colistin therapy for the treatment of intracranial abscess formations. Based on these findings, increasing the intraventricular application interval paralleled with intravenous colistin could possibly be sufficient to achieve appropriate therapeutic drug levels. Further studies are needed to support alternative dosing strategies in similar cases.

For aligning DNA sequences that differ only by sequencing errors, or by equivalent errors from other sources, a greedy algorithm can be much faster than traditional dynamic programming approaches and yet produce an alignment that is guaranteed to be theoretically optimal. We introduce a new greedy alignment algorithm with particularly good performance and show that it computes the same alignment as does a certain dynamic programming algorithm, while executing over 10 times faster on appropriate data. An implementation of this algorithm is currently used in a program that assembles the UniGene database at the National Center for Biotechnology Information.

Modeling single junction solar cells composed of III–V semiconductors such as GaAs with the effects of photon recycling yields insight into design and material criteria required for high efficiencies. For a thin-film single junction GaAs cell to reach 28.5% efficiency, simulation results using a recently developed model which accounts for photon recycling indicate that Shockley–Read–Hall (SRH) lifetimes of electrons and holes must be longer than 3 and 1 μs, respectively, in a 2-μm thin active region, and that the native substrate must be removed such that the cell is coupled to a highly reflective rear-side mirror. The model is generalized to account for luminescence coupling in tandem devices, which yields direct insight into the top cell’s nonradiative lifetimes. A heavily current mismatched GaAs/GaAs tandem device is simulated and measured experimentally as a function of concentration between 3 and 100 suns. The luminescence coupling increases from 14% to 33% experimentally, whereas the model requires increasing electron and hole SRH lifetimes to explain these results. This could be an indication of the saturating defects which mediate the SRH process. However, intermediate GaAs layers between the two subcells may also contribute to the luminescence coupling as a function of concentration.

Large numbers of MS/MS peptide spectra generated in proteomics experiments require efficient, sensitive and specific algorithms for peptide identification. In the Open Mass Spectrometry Search Algorithm (OMSSA), specificity is calculated by a classic probability score using an explicit model for matching experimental spectra to sequences. At default thresholds, OMSSA matches more spectra from a standard protein cocktail than a comparable algorithm. OMSSA is designed to be faster than published algorithms in searching large MS/MS datasets. Keywords: protein identification • algorithm • bioinformatics • mass spectrometry • proteomics • significance testing

In addition to maintaining the GenBank(R) nucleic acid sequence database, the National Center for Biotechnology Information (NCBI) provides data analysis and retrieval resources for the data in GenBank and other biological data made available through NCBI's website. NCBI resources include Entrez, PubMed, PubMed Central, LocusLink, the NCBI Taxonomy Browser, BLAST, BLAST Link (BLink), Electronic PCR, OrfFinder, Spidey, RefSeq, UniGene, HomoloGene, ProtEST, dbMHC, dbSNP, Cancer Chromosome Aberration Project (CCAP), Entrez Genomes and related tools, the Map Viewer, Model Maker, Evidence Viewer, Clusters of Orthologous Groups (COGs) database, Retroviral Genotyping Tools, SARS Coronavirus Resource, SAGEmap, Gene Expression Omnibus (GEO), Online Mendelian Inheritance in Man (OMIM), the Molecular Modeling Database (MMDB), the Conserved Domain Database (CDD) and the Conserved Domain Architecture Retrieval Tool (CDART). Augmenting many of the web applications are custom implementations of the BLAST program optimized to search specialized data sets. All of the resources can be accessed through the NCBI home page at: http://www.ncbi.nlm.nih.gov.

In addition to maintaining the GenBank(R) nucleic acid sequence database, the National Center for Biotechnology Information (NCBI) provides data analysis and retrieval resources for the data in GenBank and other biological data made available through NCBI's Web site. NCBI resources include Entrez, PubMed, PubMed Central (PMC), LocusLink, the NCBITaxonomy Browser, BLAST, BLAST Link (BLink), Electronic PCR (e-PCR), Open Reading Frame (ORF) Finder, References Sequence (RefSeq), UniGene, HomoloGene, ProtEST, Database of Single Nucleotide Polymorphisms (dbSNP), Human/Mouse Homology Map, Cancer Chromosome Aberration Project (CCAP), Entrez Genomes and related tools, the Map Viewer, Model Maker (MM), Evidence Viewer (EV), Clusters of Orthologous Groups (COGs) database, Retroviral Genotyping Tools, SAGEmap, Gene Expression Omnibus (GEO), Online Mendelian Inheritance in Man (OMIM), the Molecular Modeling Database (MMDB), the Conserved Domain Database (CDD), and the Conserved Domain Architecture Retrieval Tool (CDART). Augmenting many of the Web applications are custom implementations of the BLAST program optimized to search specialized data sets. All of the resources can be accessed through the NCBI home page at: http://www.ncbi.nlm.nih.gov.

Gene expression quantifying techniques promise to shape our understanding of the distribution and regulation of the products of transcription in normal and abnormal cell types. cDNA microarray (DeRisi 1997), high-density oligo DNA array (Wodicka 1997) and serial analysis of gene expression (Velculescu 1995) techniques have all been developed to quickly and efficiently survey genome-wide transcript expression. However, each of these techniques has the potential to produce, in a single experiment, vast amounts of data which must be sifted and ordered for useful information to become apparent. Additional challenges are met when attempts are made to compare, merge and contrast data from experiments conducted under differing conditions and locales. As a prototype for the handling, analysis and exchange of gene expression data in the public forum, we have undertaken the production of a public repository and resource for a particular set of gene expression data, i.e., serial analysis of gene expression (SAGE) data. This repository was designed initially to archive SAGE data produced through the Cancer Genome Anatomy Project (CGAP) (Strausberg 1997; http://www.ncbi.nlm.nih.gov/cgap) but is now capable of accepting submissions of SAGE sequence data from any source, without fee or restriction on dissemination or use. It is our goal to provide free and open access to raw SAGE sequence data, precomputed tag extractions, and several modest analysis tools. This resource currently contains over two million tags from 47 SAGE libraries. We call this resource SAGEmap. Its two online components are available via the World Wide Web (http://www.ncbi.nlm.nih.gov/sage) and anonymous FTP (ftp://ncbi.nlm.nih.gov/pub/sage).