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Please cite this article as: A. Romero, C. Jiménez, J. González, P. López-Varo, M.J. Deen, J.A. Jiménez-Tejada, Compact modeling of the effects of illumination on the contact region of organic phototransistors, Organic Electronics, (2019), 70, 113-121., A good modeling of degrading effects in an electronic device, such as the contact region of organic phototransistors (OPTs), can be favorably used to better describe and optimize the performance of the whole device. Furthermore, a proper design of the contacts can enhance the exciton dissociation and the extraction of photogenerated charge in the device. In this work, a compact model for OPTs is developed. This model is valid for all the operation regimes of the transistors. It includes a model for the contact region of the device that incorporates the effects of illumination. The compact model and the contact region model are validated with published experimental data from several OPTs under different illumination conditions. The tool used to validate the model is an evolutionary parameter extraction procedure developed in a previous work. The results show that both photoconductive and photovoltaic effects impact the intrinsic region of the transistor, as well as the electrical behavior of the contact region. The parameters used in the contact region model are linked to these photovoltaic and photoconductive effects., This work was supported by projects MAT2016-76892-C3-3-R and TIN2015-67020-P funded by the Spanish Government and European Regional Development Funds (ERDF) and by “Beca de Iniciación a la Investigación para estudiantes de Grado” given by the University of Granada.

López Varo, Pilar et al., Solar energy conversion using semiconductors to fabricate photovoltaic devices relies on efficient light absorption, charge separation of electron-hole pair carriers or excitons, and fast transport and charge extraction to counter recombination processes. Ferroelectric materials are able to host a permanent electrical polarization which provides control over electrical field distribution in bulk and interfacial regions. In this review, we provide a critical overview of the physical principles and mechanisms of solar energy conversion using ferroelectric semiconductors and contact layers, as well as the main achievements reported so far. In a ferroelectric semiconductor film with ideal contacts, the polarization charge would be totally screened by the metal layers and no charge collection field would exist. However, real materials show a depolarization field, smooth termination of polarization, and interfacial energy barriers that do provide the control of interface and bulk electric field by switchable spontaneous polarization. We explore different phenomena as the polarization-modulated Schottky-like barriers at metal/ferroelectric interfaces, depolarization fields, vacancy migration, and the switchable rectifying behavior of ferroelectric thin films. Using a basic physical model of a solar cell, our analysis provides a general picture of the influence of ferroelectric effects on the actual power conversion efficiency of the solar cell device, and we are able to assess whether these effects or their combinations are beneficial or counterproductive. We describe in detail the bulk photovoltaic effect and the contact layers that modify the built-in field and the charge injection and separation in bulk heterojunction organic cells as well as in photocatalytic and water splitting devices. We also review the dominant families of ferroelectric materials that have been most extensively investigated and have provided the best photovoltaic performance., The research leading to these results has received funding from the European Union Seventh Framework Program [FP7/2007–2013] under grant agreement 316494 and from MINECO of Spain under project TEC2013-47283-R and Grant FPU12/02712. F.R. acknowledges funding and partial salary support for work on multiferroic materials from NSERC, through an EWR Steacie Memorial Fellowship.

Special issue Integrated study of a deep submarine canyon and adjacent open slopes in the Western Mediterranean Sea: an essential habitat.-- 13 pages, 7 figures, 2 tables, To characterize the temporal and spatial variability of total mass fluxes in the Blanes submarine canyon and the nearby southern open slope, eight near-bottom sediment traps were deployed at 300, 900, 1200 and 1500m along the canyon axis, and at 900, 1200, 1500 and 1800m of water depth on the southern open slope from November 2008 to November 2009. The results obtained show that mass fluxes were higher into the canyon, ranging from 0.05 to 82.67gm-2d-1, compared with those from the open slope that ranged from 0.01 to 9.91gm2d-1. Both environments were highly influenced by atmospheric forcing and showed increased total mass fluxes during autumn and winter months. The spatial distribution of total mass fluxes and major constituents (organic matter, carbonate, opal and lithogenics) highlights the contrasts amongst the two physiographic domains in the study area (canyons vs. open slope). The temporal evolution of particle fluxes shows three distinct situations succeeding each other along the year. These are determined by: (1) storms in autumn and winter, driving 60% of the annual total mass flux in Blanes Canyon and 44% in the open slope stations, and also 60% and 40% of the annual OC flux in Blanes Canyon and the southern open slope, respectively; (2) open sea convection in late winter and spring, which is accompanied by a phytoplankton bloom and drives 13% of the settling OC in the canyon and 34% in the open slope; and (3) dust inputs and resuspension by bottom trawling in late spring and -summer months, driving 17% of the annual OC flux in the canyon and 18% in the slope. © 2013 Elsevier Ltd., This research has been supported by Spanish and EU funded projects PROMETEO (CTM2007-66316-C02-01/MAR), DOS MARES (CTM2010-21810-C03-01), GRACCIE-CONSOLIDER (CSD2007-00067), PERSEUS (GA 287600) and REDECO (CTM2008-04973-E/MAR) RTD projects. University of Barcelona researchers are supported by grant 2009 SGR 1305 of Generalitat de Catalunya. P.L.F. benefited from a Spanish FPI Grant (BES-2008-009374)

Chemical analysis of the secondary metabolite pattern of the gorgonian Echinogorgia complexa , collected along South Indian coasts, showed the presence of two new tricyclic guaiane furanosesquiterpenes, iso -echinofuran ( 3 ) and 8,9-dihydro-linderazulene ( 4 ), co-occurring with the known echinofuran ( 5 ) and structurally related to the pigment linderazulene ( 1 ). The unprecedented molecules 3 and 4 were characterized by spectral methods, mainly by NMR techniques. Compounds 3 – 5 displayed moderate activity in the mitochondrial respiratory chain inhibition assay.