Wolfram Witte
YOU?
Author Swipe
Progress Toward Efficient Wide‐Gap Cu (In,Ga)(S,Se) <sub>2</sub> Thin‐Film Solar Cells Open
In this paper, wide‐gap Cu (In,Ga)(S,Se) 2 thin‐film solar cells are studied in view of their performance, limitations, and opportunities for further optimization. To this end, a wide variety of properties is investigated. This includes th…
Progress Toward Efficient Wide‐Gap Cu (In,Ga)(S,Se)$_2$ Thin‐Film Solar Cells Open
In this paper, wide-gap Cu (In,Ga)(S,Se)$_2$ thin-film solar cells are studied in view of their performance, limitations, and opportunities for further optimization. To this end, a wide variety of properties is investigated. This includes …
View article: Sodium Induced Beneficial Effects in Wide Bandgap Cu(In,Ga)S <sub>2</sub> Solar Cell With 15.7% Efficiency
Sodium Induced Beneficial Effects in Wide Bandgap Cu(In,Ga)S <sub>2</sub> Solar Cell With 15.7% Efficiency Open
This study underscores the pivotal role of sodium (Na) supply in optimizing the optoelectronic properties of wide bandgap (~1.6 eV) Cu(In,Ga)S 2 (CIGS) thin‐film absorbers for high‐efficiency solar cells. Our findings demonstrate that the …
Role of light and heavy alkalis in Cu(In,Ga)Se <sub>2</sub> absorbers Open
In this work, we investigate the distribution of single- and co-doped alkali elements—sodium (Na), potassium (K), and rubidium (Rb)—within the bulk and grain boundaries (GBs) of Cu(In,Ga)Se ₂ (CIGSe) thin-film solar cells, and examine thei…
Assessment of transparent conductive oxides as back contacts for inline-fabricated Cu(In,Ga)Se<sub>2</sub> solar cells Open
The integration of transparent back contacts (TBCs) into Cu(In,Ga)Se 2 (CIGS) and (Ag,Cu)(In,Ga)Se 2 thin-film solar cells presents significant opportunities for enhancing device performance and enabling applications such as bifacial and t…
Explainable Artificial Intelligence Driven Methodology for Accelerated Research of Complex Systems: Case Study of Thin‐Film Photovoltaic Kesterite‐Based Technology Open
Materials research increasingly targets systems of higher structural and compositional complexity, which hinders their understanding and slows down technological development. To address this, an explainable artificial intelligence (XAI)‐dr…
View article: Sodium induced beneficial effects in wide bandgap Cu(In,Ga)S2 solar cell with 15.7% efficiency
Sodium induced beneficial effects in wide bandgap Cu(In,Ga)S2 solar cell with 15.7% efficiency Open
This study underscores the pivotal role of sodium (Na) supply in optimizing the optoelectronic properties of wide bandgap (~1.6 eV) Cu(In,Ga)S2 (CIGS) thin film absorbers for high efficiency solar cells. Our findings demonstrate that the s…
Structural analyses and photovoltaic device simulations in two and three dimensions applied to Ag-alloyed Cu(In,Ga)Se<sub>2</sub> solar cells Open
The present study reports on the structural changes and related photovoltaic properties resulting from the addition of Ag in Cu(In,Ga)Se 2 (CIGS)-based thin-film solar cells analysed using two-dimensional (2D) and three-dimensional (3D) an…
Impact of a Thin Sacrificial Mo Layer on the Formation of the Wide Band Gap ACIGSe Absorber/ITO Thin-Film Solar Cell Interface Open
The effect of a thin sacrificial Mo interlayer on the device performance of a thin-film solar cell based on a wide band gap (1.46 eV) (Ag, Cu)(In, Ga)Se2 (ACIGSe)/indium tin oxide (ITO) layer stack and its influence on the chemical composi…
View article: X‐Ray and Electron Spectroscopy of the CdS/(Ag,Cu)(In,Ga)Se<sub>2</sub> Interface With RbF Treatment
X‐Ray and Electron Spectroscopy of the CdS/(Ag,Cu)(In,Ga)Se<sub>2</sub> Interface With RbF Treatment Open
The chemical and electronic structure of the CdS/(Ag,Cu)(In,Ga)Se 2 (CdS/ACIGSe) interface for thin‐film solar cells, involving an absorber with a bulk [Ag]/([Ag]+[Cu]) (AAC) ratio of 0.06, a state‐of‐the‐art RbF post‐deposition treatment …
Impact of a RbF post-deposition treatment on the chemical structure of wide-gap CuIn0.1Ga0.9Se2 thin-film solar cell absorber surfaces Open
A detailed characterization of the impact of a RbF post-deposition treatment (RbF-PDT) on the chemical structure of a wide-gap Cu(In, Ga)Se2 thin-film solar cell absorber surface with a high Ga/(Ga + In) (GGI) ratio of 0.9 is presented. Us…
Ordered Vacancy Compound Formation at the Interface of Cu(In,Ga)Se<sub>2</sub> Absorber with Sputtered In<sub>2</sub>S<sub>3</sub>‐Based Buffers: An Atomic‐Scale Perspective Open
The design of a Cd‐free and wider‐bandgap buffer layer is stringent for future Cu(In,Ga)Se 2 (CIGSe) thin‐film solar cell applications. For that, an In 2 S 3 buffer layer alloyed with a limited amount of O (well below 25 mol%) has been pro…
Effect of Ga Variation on the Bulk and Grain‐Boundary Properties of Cu(In,Ga)Se<sub>2</sub> Absorbers in Thin‐Film Solar Cells and Their Impacts on Open‐Circuit Voltage Losses Open
Polycrystalline widegap Cu(In,Ga)Se 2 (CIGSe) absorbers for top cells in photovoltaic tandem devices can be synthesized via [Ga]/([Ga] + [In]) (GGI) ratios of > 0.5. However, the power conversion efficiencies of such high‐GGI devices are s…
Role of Ag Addition on the Microscopic Material Properties of (Ag,Cu)(In,Ga)Se<sub>2</sub> Absorbers and Their Effects on Losses in the Open‐Circuit Voltage of Corresponding Devices Open
Ag alloying of Cu(In,Ga)Se 2 (CIGSe) absorbers in thin‐film solar cells leads to improved crystallization of these absorber layers at lower substrate temperatures than for Ag‐free CIGSe thin films as well as to enhanced cation interdiffusi…
Influence of oxygen content on the properties of In2(OxS1−x)3 used as buffer material in Cu(In,Ga)Se2 solar cells Open
We investigate magnetron-sputtered In2(OxS1−x)3 compounds acting as an alternative buffer system to the solution-grown CdS or Zn(O,S) buffer layers in Cu(In,Ga)Se2 (CIGS) thin-film solar cells. The influence of the oxygen content on the so…
Rb Diffusion and Oxide Removal at the RbF-Treated Ga<sub>2</sub>O<sub>3</sub>/Cu(In,Ga)Se<sub>2</sub> Interface in Thin-Film Solar Cells Open
We report on the chemical structure of Cu(In,Ga)Se2 (CIGSe) thin-film solar cell absorber surfaces and their interface with a sputter-deposited Ga2O3 buffer. The CIGSe samples were exposed to a RbF postdeposition treatment and an ammonia-b…
Chemical phases in the solution-grown Zn(O,S) buffer of post-annealed Cu(In,Ga)Se2 solar cells investigated by transmission electron microscopy and electroreflectance Open
Thin-film solar cells with Cu(In,Ga)Se2 (CIGS) absorber layers have been intensively studied due to their high power conversion efficiencies. CIGS solar cells with Zn(O,S) buffer layers achieved record efficiencies due to their reduced par…
Metastable Defects Decrease the Fill Factor of Solar Cells Open
Cu(In,Ga)Se2-based solar cells exceed power conversion efficiencies of 23%. However, the fill factor of these solar cells, with best values around 80%, is relatively low (Si reaches 84.9%) mostly due to diode factors greater than 1. Recent…
Improvement of Quantitative STEM/EDXS Analyses for Chemical Analysis of Cu(In,Ga)Se2 Solar Cells with Zn(O,S) Buffer Layers Open
Energy-dispersive X-ray spectroscopy (EDXS) in a transmission electron microscope is frequently used for the chemical analysis of Cu(In,Ga)Se2 (CIGS) solar cells with high spatial resolution. However, the quantification of EDXS data is com…
Effects of material properties of band‐gap‐graded Cu(In,Ga)Se<sub>2</sub> thin films on the onset of the quantum efficiency spectra of corresponding solar cells Open
Polycrystalline Cu(In,Ga)Se 2 (CIGSe) thin‐film solar cells exhibit gradual onset in their external quantum efficiency ( EQE ) spectra whose shape can be affected by various CIGSe material properties. Apart from influences on the charge‐ca…
Metastable defects decrease the fill factor of solar cells Open
Cu(In,Ga)Se2 based solar cells exceed power conversion efficiencies of 23 %. Yet, the fill factor of these solar cells, with best values around 80 %, is relatively low (Si reaches 84.9%) mostly due to diode factors greater than one. Recent…
Using the inelastic background in hard x-ray photoelectron spectroscopy for a depth-resolved analysis of the CdS/Cu(In,Ga)Se2 interface Open
The inelastic background of hard x-ray photoelectron spectroscopy data is analyzed to paint a depth-resolved picture of the CdS/Cu(In,Ga)Se2 (CdS/CIGSe) layer structure. The CdS/CIGSe interface is the central component in next-generation c…
Improved quantitative chemical analyses of Cu(In,Ga)Se<sub>2</sub> solar cells performed by STEM/EDXS Open
An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.
How band tail recombination influences the open‐circuit voltage of solar cells Open
The power conversion efficiency of solar cells strongly depends on the open‐circuit voltage which, in turn, depends on the recombination activity within the device. A possible source of detrimental charge carrier recombination is band tail…
Effects of Sputtered In<sub>x</sub>S<sub>y</sub> Buffer on CIGS with RbF Post-Deposition Treatment Open
Indium sulfide (In x S y ) is an attractive candidate to be used as a buffer layer for Cu(In,Ga)Se 2 (CIGS) thin-film solar cells and modules. In x S y sputtering would be the preferred deposition method of choice as it allows for much hig…
Microscopic origins of performance losses in highly efficient Cu(In,Ga)Se2 thin-film solar cells Open
Thin-film solar cells based on polycrystalline absorbers have reached very high conversion efficiencies of up to 23-25%. In order to elucidate the limiting factors that need to be overcome for even higher efficiency levels, it is essential…
Electrostatic potential fluctuations and light‐soaking effects in Cu(In,Ga)Se<sub>2</sub> solar cells Open
In Cu(In,Ga)Se 2 (CIGS) thin‐film solar cells, laterally inhomogeneous distributions of point defects may induce electrostatic potential fluctuations and thus reduce the open‐circuit voltage ( V oc ). In the present work, we investigate po…
Influence of Substrate Temperature during InxSy Sputtering on Cu(In,Ga)Se2/Buffer Interface Properties and Solar Cell Performance Open
Indium sulfide (InxSy)—besides CdS and Zn(O,S)—is already used as a buffer layer in chalcopyrite-type thin-film solar cells and modules. We discuss the influence of the substrate temperature during very fast magnetron sputtering of InxSy b…