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Dive into the research topics where F. Frühauf is active.

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Featured researches published by F. Frühauf.


IEEE Journal of Photovoltaics | 2016

An Improved Method to Measure the Point Spread Function of Cameras Used for Electro- and Photoluminescence Imaging of Silicon Solar Cells

Otwin Breitenstein; F. Frühauf; Anthony Teal

When silicon solar cells are investigated by electro- or photoluminescence (PL) imaging using a silicon-based camera, photon scattering in the detector chip leads to a certain degree of blurring of the images, which can be removed by image deconvolution. The necessary point spread function (PSF) was originally measured directly by evaluating fine light spots, but this procedure needed the evaluation of several images. It was shown recently that evaluating an image with a sharp contrast edge in the middle may lead to a PSF spreading over longer distances by evaluating only one image. Here, we show that the previous backwards substitution method for obtaining this PSF does still lead to residual errors. An alternative method to derive the PSF from a measured contrast edge image is introduced here. It uses an iterative method, which leads to most precise results. In addition to the local deconvolution, nonlocal (homogeneous) light scattering is corrected. The correct reconstruction of the dark part of the image used for obtaining the PSF is a proof for the accuracy of this PSF.


IEEE Journal of Photovoltaics | 2016

Effective Diffusion Length and Bulk Saturation Current Density Imaging in Solar Cells by Spectrally Filtered Luminescence Imaging

Otwin Breitenstein; F. Frühauf; David Hinken; Karsten Bothe

Most methods for interpreting electroluminescence (EL) or photoluminescence (PL) images of solar cells evaluate the local diode voltages but not the local luminescence intensity itself. One exception is the Fuyuki approximation, which assumes that the local value of the luminescence signal is proportional to the local effective diffusion length. This dependence has been derived for infinitely thick solar cells and neglects self-absorption of the luminescence photons. However, for real solar cells and imaging conditions, with increasing diffusion length, the luminescence signal approaches a limiting value; hence, the Fuyuki approximation no longer holds. In this paper, we compare EL and PL images of multicrystalline solar cells using different kinds of light filtering and find that gentle shortpass filtering is useful for avoiding optical artifacts. Based on earlier calculations, a physically founded formula for the dependence of the gently shortpass-filtered luminescence signal on the bulk diffusion length, for a given rear surface recombination velocity, is presented. Since this formula only barely allows us to calculate the diffusion length from the luminescence signal, a simplified approximate formula is proposed, and its accuracy is checked. This method is tested on EL and Voc PL images of solar cells. We find that for a typical industrial multicrystalline Albackside solar cell, the obtained effective diffusion length images correlate well with such images obtained by spectral LBIC image evaluation. In addition, the saturation current density images correlate well with such images obtained by dark lock-in thermography, which show a much lower spatial resolution. The main limitation of the proposed method is that it is basically approximate and needs some fitting parameters.


Solar Energy Materials and Solar Cells | 2016

Laplacian photoluminescence image evaluation employing image deconvolution

F. Frühauf; Otwin Breitenstein


Solar Energy Materials and Solar Cells | 2016

Improved empirical method for calculating short circuit current density images of silicon solar cells from saturation current density images and vice versa

Otwin Breitenstein; F. Frühauf; M. Turek


Solar Energy Materials and Solar Cells | 2017

Finite element simulation of inhomogeneous solar cells based on lock-in thermography and luminescence imaging

F. Frühauf; Johnson Wong; Jan S. Bauer; Otwin Breitenstein


Solar Energy Materials and Solar Cells | 2016

Description of the local series resistance of real solar cells by separate horizontal and vertical components

F. Frühauf; Yassine Sayad; Otto Breitenstein


Solar Energy Materials and Solar Cells | 2017

Quantitative local current-voltage analysis and calculation of performance parameters of single solar cells in modules

Jan S. Bauer; F. Frühauf; Otwin Breitenstein


Energy Procedia | 2016

Local Solar Cell Efficiency Analysis Performed by Injection-dependent PL Imaging (ELBA) and Voltage-dependent Lock-in Thermography (Local I-V)☆

Otwin Breitenstein; F. Frühauf; Jan S. Bauer; Florian Schindler; Bernhard Michl


Solar Energy Materials and Solar Cells | 2017

DLIT- versus ILIT-based efficiency imaging of solar cells

F. Frühauf; Otwin Breitenstein


Solar Energy Materials and Solar Cells | 2017

Alternative luminescence image evaluation – Comparison with lock-in thermography

Otwin Breitenstein; F. Frühauf

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Johnson Wong

National University of Singapore

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AnYao Liu

Australian National University

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Anthony Teal

University of New South Wales

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Daniel Macdonald

Australian National University

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Keith R. McIntosh

Australian National University

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