A5008175438- Chalcogenide Semiconductor Thin Films
- Quantum Dots Synthesis And Properties
- Copper-based nanomaterials and applications
- Semiconductor materials and interfaces
- Phase-change materials and chalcogenides
- Electron and X-Ray Spectroscopy Techniques
- Robotics and Sensor-Based Localization
- Advanced Materials Characterization Techniques
- Silicon and Solar Cell Technologies
- solar cell performance optimization
- Ion-surface interactions and analysis
- Crystal Structures and Properties
- Thin-Film Transistor Technologies
- Indoor and Outdoor Localization Technologies
- X-ray Spectroscopy and Fluorescence Analysis
- Video Surveillance and Tracking Methods
- Glycosylation and Glycoproteins Research
- 3D Surveying and Cultural Heritage
- Semiconductor Quantum Structures and Devices
- UAV Applications and Optimization
- Advanced Electron Microscopy Techniques and Applications
- Advanced SAR Imaging Techniques
- Solid-state spectroscopy and crystallography
- Advanced Thermoelectric Materials and Devices
- Metal Extraction and Bioleaching
Instituto de Óptica "Daza de Valdés"
2023-2024
Universidad Autónoma de Madrid
2014-2023
Center for Advanced Aerospace Technologies
2020-2023
Universidad Complutense de Madrid
1987-2022
Helmholtz-Zentrum Berlin für Materialien und Energie
2008-2018
Physikalisch-Technische Bundesanstalt
2014
Universidad de Sevilla
2013
Technische Universität Berlin
2010
German Orient Foundation
2008-2009
Hartford Financial Services (United States)
2008
A series of Cu(In,Ga)Se2 (CIGS) thin film solar cells with differently prepared heterojunctions has been investigated by admittance spectroscopy, capacitance-voltage (CV) profiling, and temperature dependent current-voltage (IVT) measurements. The devices different CdS buffer layer thicknesses, an In2S3 or a Schottky barrier junction, all show the characteristic step at shallow energies between 40 160 meV, which often referred to as N1 defect. No correlation thickness capacitance is found....
Abstract The performance‐boosting effect of alkali treatments is well known for chalcogenide thin‐film solar cells based on Cu(In,Ga)Se 2 (CIGS) and Cu ZnSn(S,Se) 4 (CZTSSe–kesterite) absorbers. In contrast to heavier elements, lithium expected alloy with the kesterite phase leading solid solution (Li x 1− ) (LCZTSSe), which offers a way tuning semiconductor bandgap by changing ratio Li/(Li+Cu). Here presented an experimental series solution‐processed LCZTSSe fraction Li/(Li+Cu) ranging from...
Abstract Serious games have proven to be a powerful tool in education engage, motivate, and help students learn. However, the change student knowledge after playing is usually measured with traditional (paper) prequestionnaires–postquestionnaires. We propose combination of game learning analytics data mining techniques predict based on in‐game interactions. tested this approach case study for which we conducted preexperiments–postexperiments 227 previously validated serious first aid...
ABSTRACT In order to transfer the potential for high efficiencies seen Cu(In,Ga)Se 2 (CIGSe) thin films from co‐evaporation processes cheaper large‐scale deposition techniques, a more intricate understanding of CIGSe growth process high‐quality material is required. Hence, mechanism chalcopyrite‐type when varying Cu content during multi‐stage studied. Break‐off experiments help understand intermediate stages thin‐film formation. The film structure and morphology are studied by X‐ray...
This work presents results from high-resolution scanning transmission electron microscopy and energy-loss spectroscopy on twin boundaries (TBs) nontwin grain (GBs) in Cu(In,Ga)Se(2) thin films. It is shown that the atomic reconstruction different for symmetries of boundaries. We are able to confirm model proposed by Persson Zunger [Phys. Rev. Lett. 91, 266401 (2003)] Se-Se-terminated Σ3 {112} TBs, showing Cu depletion In enrichment two planes closest TB. On contrary, without detected a...
This paper discusses the advantages of pulsed laser atom-probe tomography (APT) to analyze Cu(In,Ga)Se <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -based solar cells. Electron backscatter diffraction (EBSD) was exploited for site-specific preparation APT samples at selected grain boundaries. approach is very helpful not only determine location boundaries but also classify them as well. We demonstrate that correlative transmission...
Abstract Grain boundaries (GBs) in polycrystalline Cu(In,Ga)Se 2 thin films exhibit only slightly enhanced recombination, as compared with the grain interiors, allowing for very high power‐conversion efficiencies of more than 20% corresponding solar‐cell devices. This work highlights specific compositional and electrical properties GBs by application appropriate subnanometer characterisation techniques: inline electron holography, energy‐loss spectroscopy, atom‐probe tomography. It is found...
The present work shows results on elemental distribution analyses in Cu(In,Ga)Se2 thin films for solar cells performed by use of wavelength-dispersive and energy-dispersive X-ray spectrometry (EDX) a scanning electron microscope, EDX transmission photoelectron, angle-dependent soft emission, secondary ion-mass (SIMS), time-of-flight SIMS, sputtered neutral mass, glow-discharge optical emission Auger electron, Rutherford backscattering spectrometry, microscopy, Raman depth profiling, mapping,...
The abbreviations used are: MAP, microtubule-associated protein; MES, 2-(N-morpholino)ethanesulfonic acid; EGTA, [ethylenebis(oxyethylenenitrilo)]tetraacetic PIPES, 1,4-piperazinediethanesulfonic SDS, sodium dodecyl sulfate; PMSF, phenylmethylsulfonyl fluoride; S-tubulin, subtilisin-digested tubulin.lanski et al. ( 16).Tubulin depleted of MAPS was obtained by phosphocellulose chromatography as described Weingarten (17).Proteolytic Digestion-Tubulin, sometimes labeled with 3H in the tyrosine...
There are still open questions regarding the nature of positive effect presence Na on performance Cu(In,Ga)Se2 based, chalcopyrite thin film solar cells, especially at low processing temperatures. Studying devices fabricated from low-temperature coevaporated absorbers polyimide substrates by admittance and J-V-T measurements, characteristic properties identified for different amounts present during growth. A roll-over behavior can be directly correlated with Na-content. X-ray photoelectron...
The unusual optoelectronic properties of chalcopyrite grain boundaries (GBs) have become the subject an intense debate in recent years. In this work we investigate defect density at GBs Cu(In,Ga)Se2 by scanning tunneling spectroscopy. Contrary to our expectation, results give evidence for a reduced deep level defects and point increased levels resonance with lower conduction band GBs. Our findings imply low recombination activity GBs, thus can explain impact on efficiency based solar cells.
Metastabilities in Cu(In,Ga)Se2 (CIGS)-based solar cells induced by red light illumination, blue and voltage bias treatment are investigated admittance spectroscopy, capacitance-voltage profiling, thermally stimulated capacitance, temperature dependent current-voltage (IVT) measurements. It is found that the characteristic N1-admittance response exhibits changes activation energy after soaking forward treatment, whereas no significant change of observed reverse treatment. A roll-over effect...
Abstract We report a total‐area efficiency of 15.9% for flexible Cu(In,Ga)Se 2 thin film solar cells on polyimide foil (cell area 0.95 cm ). The absorber layer was grown by multi‐stage deposition process at maximum nominal temperature 420°C. Na added via evaporation NaF prior to the leading an enhanced V oc and FF. Growth conditions device characterization are described. Copyright © 2011 John Wiley & Sons, Ltd.
Abstract This paper provides an overview of the physical vapor technologies used to synthesize Cu 2 ZnSn(S,Se) 4 thin films as absorber layers for photovoltaic applications. Through years, CZT(S,Se) have been fabricated using sequential stacking or co-sputtering precursors well co-evaporation elemental sources, leading high-efficient solar cells. In addition, pulsed laser deposition composite targets and monograin growth by molten salt method were developed alternative methods kesterite...
Cross section electron-beam induced current (EBIC) and illumination-dependent voltage (IV) measurements show that charge carrier transport in Cu(In,Ga)Se2 (CIGSe)/CdS/ZnO solar-cells is generation-dependent. We perform a detailed analysis of CIGSe solar cells with different CdS layer thicknesses varying Ga-content the absorber layer. In conjunction numerical simulations, EBIC IV data are used to develop consistent model for defect distributions focus on heterojunction region. The best...
ABSTRACT Thin film Cu(In , Ga)Se 2 (CIGSe) solar cells deposited on flexible steel foil substrates by coevaporation are investigated. Iron diffusion from the substrate material into CIGSe absorber layers is studied secondary ion mass spectroscopy (SIMS) for different maximum growth temperatures and cell back‐contact configurations. The optimization of temperature, introduction a barrier layer at back contact, adjustment sodium doping lead to device efficiencies above 14%. Defect means...
Abstract Polycrystalline CuIn 1− x Ga Se 2 (CIGS) thin films were deposited by the non‐vacuum, near‐atmospheric‐pressure selenization of stacked metallic precursor layers. A study was carried out to investigate influence significant factors absorber on solar cells performance. An efficiency enhancement obtained for Cu/(In+Ga) atomic ratios between 0·93 and 0·95. The slope observed energy bandgap grading showed a strong V OC short circuit current density J SC . increase content in active...