Examinando por Autor "del Pozo, Gonzalo"

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Analysing impact of oxygen and water exposure on roll-coated organic solar cell performance using impedance spectroscopy
(Elsevier, 2018-12-28) Arredondo, Belén; Romero, Beatriz; Beliatis, MJ; del Pozo, Gonzalo; Martin-Martin, Diego; Blakesley, JC; Dibb, G; Krebs, FC; Gevorgyan, SA; Castro, Fernando
In this work we study the degradation of roll-coated flexible inverted organic solar cells in different atmospheres. We demonstrate that impedance spectroscopy is a powerful tool for elucidating degradation mechanisms; it is used here to distinguish the different degradation mechanisms due to water and oxygen. Identical cells were exposed to different accelerated degradation environments using water only, oxygen only, and both water and oxygen simultaneously, all of them enhanced with UV light. The photocurrent is dramatically reduced in the oxygen-degraded samples. Impedance measurements indicate that this phenomenon is attributed to defects introduced by absorption of oxygen, which results in an increase of the acceptor impurity (NA) at the cathode interface obtained from a Mott-Schottky analysis. Simultaneously, at the anode interface where PEDOT:PSS is not shielded by the substrate, the nature of degradation differs for the water and oxygen degraded samples. While oxygen + UV light decreases the conductivity of the PEDOT:PSS layer, water + UV light changes the PEDOT:PSS work function inducing a depletion region at the anode.
Apuntes IEE-IOI(Vicálvaro)
(2023-12-19) del Pozo, Gonzalo
Apuntes de la asignatura al completo
Ejercicios Resueltos y exámenes
(2023-12-19) del Pozo, Gonzalo
Guía IEE-IOI(Vicálvaro) Completa
(2023-12-19) del Pozo, Gonzalo
Guía completa de la asignatura de IEE del grado de Ingeniería en Organización Industrial
Guía IEE-IOI(Vicálvaro) Completa
(2023-12-19) del Pozo, Gonzalo
Colección de problemas resueltos y enunciados de exámenes de cursos anteriores
High stable CsFAPbIBr perovskite solar cells with dominant bulk recombination at real operating temperatures
(Royal Society of Chemistry, 2023-05-02) Romero, Beatriz; Delgado, silvia; Glowienka; Chang, Cheng-Tsung; del Pozo, Gonzalo; Arredondo, Belén; Martin-Martin, Diego; Contreras, Pedro; Galagan, Yulia
Mixed-cation mixed-halide perovskite solar cells have been characterized in DC at different temperatures (from -20 degrees C up to 50 degrees C) and the time evolution of the device efficiency has been assessed using different degradation protocols (indoors and outdoors). The completely planar p-i-n structure is ITO/CuNiOx/PTAA/CsFAPbIBr/PCBM/PEI/Ag. Pristine current-voltage characteristics barely show hysteresis, at any temperature. Open circuit voltage decreases with temperature at a rate of -1.5 mV degrees C-1, and the obtained PCE temperature coefficient is lower than -0.001% K-1, which is an outstanding value for this emerging photovoltaic technology. Cells have been degraded under different protocols: indoors using different light/dark cycles and outdoors in a high temperature and high irradiation location. Cells show no significant decrease of the efficiency after more than 350 h of indoor light cycling and the estimated T-80 obtained for the sample degraded outdoors under high irradiation and high temperature conditions is similar to 15 days.
Identification of Degradation Mechanisms in Slot-Die-Coated Nonfullerene ITO-Free Organic Solar Cells Using Different Illumination Spectra
(ACS, 2020-07-27) Arredondo, Belén; del Pozo, Gonzalo; Hernández-Balaguera, Enrique; Martin-Martin, Diego; López-Gonzalez, Maria del Carmen; Romero, Beatriz; Lopez-Fraguas, Eduardo; Vergaz, Rcardo; Quintana, Xabier; Lamminaho, Jani; Destouesse, Elodie; Ahmadpour, Mehrdad; Turkovic, Vida; Madsen, Morten
In this work, we have studied degradation mechanisms of nonfullerene-based organic solar cells with PET/Ag/ZnO/ PBDTB-T:ITIC/PEDOT:PSS/CPP PEDOT:PSS device structure. We compare pristine and degraded samples that were subjected to outdoor degradation following the standard ISOS-O2 protocol. The ideality factors for different incident wavelengths obtained from open-circuit voltage vs irradiation level and current density-voltage (J-V) measurements at different temperatures indicate that for aged samples recombination is governed by the Shockley-Read-Hall mechanism occurring in a region near the anode. Samples were also characterized using impedance spectroscopy (IS) and fitted to an electrical model. Impedance parameters were used to obtain mobility, indicating a clear degradation of the active layer blend for aged samples. The change in the chemical capacitance also reveals a worsening in carrier extraction. Finally, two-dimensional (2D) numerical simulations and fits to experimental J-V curves confirm the existence of a layer near the anode contact with poorer mobility and a decrease in the anode work function (WF) for the degraded samples.
Visible Light Communication system using an organic emitter and a perovskite photodetector
(Elsevier, 2019-10-01) Lopez-Fraguas, Eduardo; Arredondo, Belén; Vega-Colado, Cesar; del Pozo, Gonzalo; Najafi, Mehrdad; Martin-Martin, Diego; Galagan, Yulia; Sanchez-Pena, José Manuel; Vergaz, Rcardo; Romero, Beatriz
The past few years have seen a great increase in the development of Visible Light Communication systems (VLC), mainly triggered by the wide variety of situations they can be used in. These communication systems have traditionally employed inorganic light emitters and photodetectors. In this work, we present a VLC system using an organic emitter and a perovskite photodetector, both fabricated using low cost processing techniques. Perovskite devices have been widely studied as photovoltaics cells since they have achieved great efficiencies, and, in the recent years, there is also an intense research of these devices as photodetectors. In this work, we have fabricated and characterized a perovskite photodetector with layer structure ITO/PTAA/Perovskite/PCBM/ BCP/Cu, and integrated it in a visible communication system to successfully link an audio signal.