Andreas W. Bett
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View article: Towards a template for epitaxial lift-off based on porous n-Si with reduced doping concentration: Increasing homogeneity and surface quality by photo-assisted etching
Towards a template for epitaxial lift-off based on porous n-Si with reduced doping concentration: Increasing homogeneity and surface quality by photo-assisted etching Open
Porous templates for the epitaxial lift-off approach (ELO) are mainly fabricated based on highly-doped p＋-Si (10-20 mcm). The pore morphology (i.e. porosity and layer homogeneity) realizable on this material is suitable for the application…
View article: Energy Research at the Fraunhofer Institute for Solar Energy Systems (2023)
Energy Research at the Fraunhofer Institute for Solar Energy Systems (2023) Open
The Fraunhofer Institute for Solar Energy Systems ISE, with a staff of about 1400, is one of the largest solar research institutes worldwide. The institute enables and contributes to achieving the energy transition which aims eventually fo…
View article: Spectrometric determination of current matching in perovskite/silicon tandem solar cells
Spectrometric determination of current matching in perovskite/silicon tandem solar cells Open
In two-terminal monolithic perovskite/silicon tandem solar cells, top and bottom cells are interconnected in series. To maximize the current of the entire tandem solar cell, current matching of the two sub-cells is needed. Thus, it is nece…
View article: Silicon concentrator cells designed for a direct mounting on compound parabolic concentrator
Silicon concentrator cells designed for a direct mounting on compound parabolic concentrator Open
A linear concentrator system consisting of a parabolic trough mirror and three-dimensional compound parabolic concentrators (CPCs) as the secondary stage was developed at Fraunhofer ISE. For this linear concentrator system and particularly…
View article: Pushing the Boundaries of Photovoltaic Light to Electricity Conversion: A GaAs Based Photonic Power Converter with 68.9% Efficiency
Pushing the Boundaries of Photovoltaic Light to Electricity Conversion: A GaAs Based Photonic Power Converter with 68.9% Efficiency Open
We present recent results achieved in the field of photonic power conversion, i.e. monochromatic light to electricity conversion, using photovoltaic cells. Based on a thin film processing approach we leverage photon recycling and optical r…
View article: 68.9% Efficient GaAs‐Based Photonic Power Conversion Enabled by Photon Recycling and Optical Resonance
68.9% Efficient GaAs‐Based Photonic Power Conversion Enabled by Photon Recycling and Optical Resonance Open
For solar cells operating under the broad‐band solar spectrum, the photovoltaic conversion efficiency is fundamentally limited by transmission and thermalization losses. For monochromatic light, these losses can be minimized by matching th…
View article: Integrated series/parallel connection for photovoltaic laser power converters with optimized current matching
Integrated series/parallel connection for photovoltaic laser power converters with optimized current matching Open
In this paper, we present a stepped architecture optimized for current matching in high‐voltage laser power converter photovoltaic (PV) cells. The integrated series/parallel connection in stepped PV cells combines the advantages of well‐kn…
View article: Terawatt-scale photovoltaics: Transform global energy
Terawatt-scale photovoltaics: Transform global energy Open
Improving costs and scale reflect looming opportunities
View article: Cover Image, Volume 27, Issue 3
Cover Image, Volume 27, Issue 3 Open
The cover image is based on the Research Article Comprehensive Electrical Loss Analysis of Monolithic Interconnected Multi-Segment Laser Power Converters by Rok Kimovec et al., https://doi.org/10.1002/pip.3075.
View article: Challenges in the design of concentrator photovoltaic (CPV) modules to achieve highest efficiencies
Challenges in the design of concentrator photovoltaic (CPV) modules to achieve highest efficiencies Open
Concentrator photovoltaics (CPV) is a special high efficiency system technology in the world of PV-technologies. The idea of CPV is to use optical light concentrators to increase the incident power on solar cells. The solar cell area is co…
View article: Comprehensive electrical loss analysis of monolithic interconnected multi‐segment laser power converters
Comprehensive electrical loss analysis of monolithic interconnected multi‐segment laser power converters Open
A method for distributed electrical modeling of complete photovoltaic monolithic interconnected modules (MIMs) with complex geometrical and electrical features is developed and applied to study electrical power losses of a six‐segment GaAs…
View article: Photonic structures for III-V//Si multijunction solar cells with efficiency >33%
Photonic structures for III-V//Si multijunction solar cells with efficiency >33% Open
Silicon based multi-junction solar cells are a promising option to overcome the theoretical efficiency limit of a silicon solar cell (29.4%). With III-V semiconductors, high bandgap materials applicable for top cells are available. For the…
View article: Component cell–based restriction of spectral conditions and the impact on CPV module power rating
Component cell–based restriction of spectral conditions and the impact on CPV module power rating Open
One approach to consider the prevailing spectral conditions when performing CPV module power ratings according to the standard IEC 62670‐3 is based on spectral matching ratios (SMRs) determined by the means of component cell sensors. In th…
View article: Analysis of the performance of an on-axis mirror module design compared to a FLATCON® module
Analysis of the performance of an on-axis mirror module design compared to a FLATCON® module Open
In this paper, the development of a HCPV mirror module design with passive heat dissipation and a geometrical concentration of 1000x is discussed. To benchmark the mirror module, the expected performance is compared to the well-known lens …
View article: Operation & maintenance – The key for reliable performance in a CPV power plant
Operation & maintenance – The key for reliable performance in a CPV power plant Open
The 44.19 MWp concentrator photovoltaic (CPV) power plant CPV 1 in Touwsrivier, South Africa is three years in operation. Lessons learnt for optimizing the power production are presented. The plant configuration is described and the key st…
View article: Multi-Segment Photovoltaic Laser Power Converters and Their Electrical Losses
Multi-Segment Photovoltaic Laser Power Converters and Their Electrical Losses Open
The electrical power losses of small area six-segment monolithic interconnected GaAs laser power converter are analyzed based on a variety of measurements and an experimentally validated numerical 2.5-dimensional distributed electrical mod…
View article: Status of Four-Junction Cell Development at Fraunhofer ISE
Status of Four-Junction Cell Development at Fraunhofer ISE Open
\nFour-junction solar cells are being developed for space applications as they promise higher efficiencies compared to the present GaInP/GaInAs/Ge triple-junction industry standard. There are multiple technological routes to achieve four-j…
View article: Performance and failure analysis of concentrator solar cells after intensive stressing with thermal, electrical, and combined load
Performance and failure analysis of concentrator solar cells after intensive stressing with thermal, electrical, and combined load Open
In this work, we investigated the impact of intensive heat loads on concentrator solar cells assemblies. As test samples, we employed lattice-matched and lattice-mismatched triple-junction solar cells made of GaInP/GaInAs/Ge. The thermal l…
View article: On the temperature dependence of dual‐junction laser power converters
On the temperature dependence of dual‐junction laser power converters Open
Dual‐junction GaAs laser power converters optimized for one monochromatic wavelength are presented, and their temperature dependence is experimentally evaluated. External quantum efficiency and irradiance‐dependent current–voltage measurem…