The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Bart Vermang - One of the best experts on this subject based on the ideXlab platform.
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dielectric based Rear Surface passivation approaches for cu in ga se2 solar cells a review
Applied Sciences, 2019Co-Authors: Gizem Birant, Jessica De Wild, Marc Meuris, Jef Poortmans, Bart VermangAbstract:This work received funding from the European Union’s H2020 research and innovation program under grant agreement No. 715027
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Rear Surface Optimization of CZTS Solar Cells by Use of a Passivation Layer With Nanosized Point Openings
IEEE Journal of Photovoltaics, 2016Co-Authors: Bart Vermang, Olivier Donzel-gargand, Christopher Frisk, Jonathan Joel, Pedro Salomé, Jérôme Borme, Sascha Sadewasser, Charlotte Platzer-björkman, Marika EdoffAbstract:Previously, an innovative way to reduce Rear interface recombination in Cu(In,Ga)(S,Se)2 (CIGSSe) solar cells has been successfully developed. In this work, this concept is established in Cu2 (Zn,Sn)(S,Se)4 (CZTSSe) cells to demonstrate its potential for other thin-film technologies. Therefore, ultrathin CZTS cells with an Al2 O3 Rear Surface passivation layer having nanosized point openings are fabricated. The results indicate that introducing such a passivation layer can have a positive impact on open-circuit voltage (VOC ; +17%rel.), short-circuit current (JSC ; +5%rel.), and fill factor (FF; +9%rel.), compared with corresponding unpassivated cells. Hence, a promising efficiency improvement of 32%rel. is obtained for the Rear passivated cells.
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highly reflective Rear Surface passivation design for ultra thin cu in ga se2 solar cells
Thin Solid Films, 2015Co-Authors: Marika Edoff, Bart Vermang, Viktor Fjallstrom, Jorn Timo Watjen, Fredrik Rostvall, Rickard Gunnarsson, Iris Pilch, Ulf Helmersson, Raja Venkata Ratan KotipalliAbstract:Al2O3 Rear Surface passivated ultra-thin Cu(In,Ga)Se2 (CIGS) solar cells with Mo nano-particles (NP) as local Rear contacts are developed to demonstrate their potential to improve optical confinement in ultra-thin CIGS solar cells. The CIGS absorber layer is 380 nm thick and the Mo NP are deposited uniformly by an up-scalable technique and have typical diameters of 150 to 200 nm. The Al2O3 layer passivates the CIGS Rear Surface between the Mo NP, while the Rear CIGS interface in contact with the Mo NP is passivated by [Ga]/([Ga] + [In]) (GGI) grading. It is shown that photon scattering due to the Mo NP contributes to an absolute increase in short circuit current density of 3.4 mA/cm2; as compared to equivalent CIGS solar cells with a standard back contact.
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improved Rear Surface passivation of cu in ga se _ bf 2 solar cells a combination of an al _ bf 2 o _ bf 3 Rear Surface passivation layer and nanosized local Rear point contacts
IEEE Journal of Photovoltaics, 2014Co-Authors: Bart Vermang, Viktor Fjallstrom, Marika EdoffAbstract:An innovative Rear contacting structure for copper indium gallium (di) selenide (CIGS) thin-film solar cells is developed in an industrially viable way and demonstrated in tangible devices. The idea stems from the silicon (Si) industry, where Rear Surface passivation layers are combined with micron-sized local point contacts to boost the open-circuit voltage (VOC) and, hence, cell efficiency. However, compared with Si solar cells, CIGS solar cell minority carrier diffusion lengths are several orders lower in magnitude. Therefore, the proposed CIGS cell design reduces Rear Surface recombination by combining a Rear Surface passivation layer and nanosized local point contacts. Atomic layer deposition of Al2O3 is used to passivate the CIGS Surface and the formation of nanosphere-shaped precipitates in chemical bath deposition of CdS to generate nanosized point contact openings. The manufactured Al2O3 Rear Surface passivated CIGS solar cells with nanosized local Rear point contacts show a significant improvement in VOC compared with unpassivated reference cells.
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development of Rear Surface passivated cu in ga se2 thin film solar cells with nano sized local Rear point contacts
Solar Energy Materials and Solar Cells, 2013Co-Authors: Bart Vermang, Viktor Fjallstrom, Jonas Pettersson, P M P Salome, Marika EdoffAbstract:For the first time, a novel Rear contacting structure for copper indium gallium (di)selenide (CIGS) thin film solar cells is discussed theoretically, developed in an industrially viable way, and demonstrated in tangible devices. The proposed cell design reduces back contacting area by combining a Rear Surface passivation layer and nano-sized local point contacts. Atomic layer deposition (ALD) of Al2O3 is used to passivate the CIGS Surface and the formation of nano-sphere shaped precipitates in chemical bath deposition (CBD) of CdS to generate point contact openings. The Al2O3 Rear Surface passivated CIGS solar cells with nano-sized local Rear point contacts show a significant improvement in open circuit voltage (VOC) compared to unpassivated reference cells. Comparing the passivated devices to solar cell capacitance simulator (SCAPS) modeling indicates that this increase is attributed to a decrease in Rear Surface recombination of a few orders.
Rolf Brendel - One of the best experts on this subject based on the ideXlab platform.
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inductively coupled plasma chemical vapour deposited alox siny layer stacks for applications in high efficiency industrial type silicon solar cells
Solar Energy Materials and Solar Cells, 2013Co-Authors: Thorsten Dullweber, Christopher Kranz, Jan Schmidt, B Beier, Boris Veith, Bjorn Roos, Oliver Hohn, Torsten Dippell, Rolf BrendelAbstract:Abstract Passivated emitter and Rear cells (PERC) are considered to be the next generation of industrial-type screen-printed silicon solar cells. Deposition methods for Rear passivation layers have to meet both the high-throughput and low-cost requirements of the PV industry in combination with high-quality Surface passivation properties. In this paper, we evaluate and optimise a novel deposition technique for AlO x passivation layers by applying an inductively coupled plasma (ICP) plasma-enhanced chemical vapour deposition (PECVD) process. The ICP AlO x deposition process enables high deposition rates up to 5 nm/s as well as excellent Surface recombination velocities below 10 cm/s after firing. A fixed negative charge of −4×10 12 cm −2 is measured for ICP AlO x single layers with an interface state density of 11.0×10 11 eV −1 cm −2 at midgap position. When applied to PERC solar cells the ICP AlO x layer is capped with a PECVD SiN y layer. We achieve independently confirmed conversion efficiencies of up to 20.1% for large-area (15.6×15.6 cm 2 ) PERC solar cells with screen-printed metal contacts and ICP AlO x /SiN y Rear side passivation on standard boron-doped Czochralski-grown silicon wafers. The internal quantum efficiency reveals an effective Rear Surface recombination velocity S Rear of (90±30) cm/s and an internal Rear reflectance R b of (91±1)% which demonstrates the excellent Rear Surface passivation of the ICP AlO x /SiN y layer stack.
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wet chemical polishing for industrial type perc solar cells
Energy Procedia, 2013Co-Authors: Christopher Kranz, Sabrina Wyczanowski, Ulrike Baumann, Katrin Weise, Cornelia Klein, F Delahaye, Thorsten Dullweber, Rolf BrendelAbstract:Abstract Industrial PERC cell process flows typically apply the polishing of the Rear side after texturing as well as the edge isolation after POCl3 diffusion. In this paper, we present a novel single step polishing process which we apply post double sided texturing and diffusion in order to remove the Rear emitter and to reduce the Rear Surface roughness. One challenge is to minimize the etch back of the front side emitter during Rear side polishing due to the reactive gas phase of the polishing process. By optimizing the polishing process, we are able to limit the increase of the emitter sheet resistance below 5 Ω/sq. However, the wet cleaning post polishing contributes an additional 20 Ω/sq emitter sheet resistance increase which is subject to further optimization. We compensate the emitter sheet resistance increase due to wet cleaning by applying a 45 Ω/sq POCl3 diffusion instead of a 60 Ω/sq diffusion. The resulting PERC solar cells with polished Rear Surface post texture and diffusion show conversion efficiencies up to 19.6% which is comparable to the reference PERC cells which apply a Rear protection layer instead of a polishing process.
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impact of the Rear Surface roughness on industrial type perc solar cells
World Conference on Photovoltaic Energy Conversion, 2012Co-Authors: Rolf Brendel, Sabrina Wyczanowski, Katrin Weise, Cornelia Klein, Thorsten Dullweber, Karsten Bothe, S Dorn, Christopher KranzAbstract:Screen-Printed PERC solar cells are a promising candidate for next-generation industrial-type solar cells. Industrial PERC cell process flows typically involve wet chemical polishing of the Rear side in order to reduce the Surface roughness and to improve the conversion efficiency. In this paper, we show that Al2O3/SiNx passivation stacks achieve an excellent Surface recombination velocity below 10 cm/s even for small polishing removal of 5 µm corresponding to rough Surfaces. In contrast, SiOx/SiNy passivation stacks exhibit a strong increase of the Surface recombination velocity up to 30 cm/s for rough Surfaces. Accordingly, we find that the efficiency of PERC solar cells with Al2O3/SiNx Rear passivation is almost independent of the polishing etch depth with best efficiencies up to 19.7% for 7.5 µm polishing removal whereas the efficiency of SiOx/SiNy Rear passivated PERC cells strongly decreases for rougher Surfaces.
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atomic layer deposited aluminum oxide for the Surface passivation of high efficiency silicon solar cells
Photovoltaic Specialists Conference, 2008Co-Authors: Jan Schmidt, Agnes Merkle, Bram Hoex, M C M Van De Sanden, W M M Kessels, Rolf BrendelAbstract:We present independently confirmed efficiencies above 20% for PERC-type solar cells with the point-contacted Rear being either passivated by atomic-layer-deposited Al 2 O 3 or by stacks consisting of an ultrathin Al 2 O 3 film and a thicker PECVD-SiO x layer. Internal quantum efficiency measurements reveal that the effective Rear Surface recombination velocities of the single-layer Al 2 O 3 -passivated cells are comparable to those measured on reference cells passivated by an aluminum-annealed thermal SiO 2 , while those of the Al 2 O 3 /SiOx-passivated cells are even lower. Very low effective Rear Surface recombination velocities of only 70 cm/s are reported for the Al 2 O 3 /SiO x stacks, including metalized areas on the cell Rear.
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20 1 efficient crystalline silicon solar cell with amorphous silicon Rear Surface passivation
Progress in Photovoltaics, 2005Co-Authors: Martin Schaper, Jan Schmidt, Heiko Plagwitz, Rolf BrendelAbstract:We have developed a crystalline silicon solar cell with amorphous silicon (a-Si:H) Rear-Surface passivation based on a simple process. The a-Si:H layer is deposited at 225°C by plasma-enhanced chemical vapor deposition. An aluminum grid is evaporated onto the a-Si:H-passivated Rear. The base contacts are formed by COSIMA (contact formation to a-Si:H passivated wafers by means of annealing) when subsequently depositing the front silicon nitride layer at 325°C. The a-Si:H underneath the aluminum fingers dissolves completely within the aluminum and an ohmic contact to the base is formed. This contacting scheme results in a very low contact resistance of 3.5 ±0.2 mΩ cm2 on low-resistivity (0.5 Ω cm) p-type silicon, which is below that obtained for conventional Al/Si contacts. We achieve an independently confirmed energy conversion efficiency of 20.1% under one-sun standard testing conditions for a 4 cm2 large cell. Measurements of the internal quantum efficiency show an improved Rear Surface passivation compared with reference cells with a silicon nitride Rear passivation. Copyright © 2005 John Wiley & Sons, Ltd.
Marika Edoff - One of the best experts on this subject based on the ideXlab platform.
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Rear Surface Optimization of CZTS Solar Cells by Use of a Passivation Layer With Nanosized Point Openings
IEEE Journal of Photovoltaics, 2016Co-Authors: Bart Vermang, Olivier Donzel-gargand, Christopher Frisk, Jonathan Joel, Pedro Salomé, Jérôme Borme, Sascha Sadewasser, Charlotte Platzer-björkman, Marika EdoffAbstract:Previously, an innovative way to reduce Rear interface recombination in Cu(In,Ga)(S,Se)2 (CIGSSe) solar cells has been successfully developed. In this work, this concept is established in Cu2 (Zn,Sn)(S,Se)4 (CZTSSe) cells to demonstrate its potential for other thin-film technologies. Therefore, ultrathin CZTS cells with an Al2 O3 Rear Surface passivation layer having nanosized point openings are fabricated. The results indicate that introducing such a passivation layer can have a positive impact on open-circuit voltage (VOC ; +17%rel.), short-circuit current (JSC ; +5%rel.), and fill factor (FF; +9%rel.), compared with corresponding unpassivated cells. Hence, a promising efficiency improvement of 32%rel. is obtained for the Rear passivated cells.
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highly reflective Rear Surface passivation design for ultra thin cu in ga se2 solar cells
Thin Solid Films, 2015Co-Authors: Marika Edoff, Bart Vermang, Viktor Fjallstrom, Jorn Timo Watjen, Fredrik Rostvall, Rickard Gunnarsson, Iris Pilch, Ulf Helmersson, Raja Venkata Ratan KotipalliAbstract:Al2O3 Rear Surface passivated ultra-thin Cu(In,Ga)Se2 (CIGS) solar cells with Mo nano-particles (NP) as local Rear contacts are developed to demonstrate their potential to improve optical confinement in ultra-thin CIGS solar cells. The CIGS absorber layer is 380 nm thick and the Mo NP are deposited uniformly by an up-scalable technique and have typical diameters of 150 to 200 nm. The Al2O3 layer passivates the CIGS Rear Surface between the Mo NP, while the Rear CIGS interface in contact with the Mo NP is passivated by [Ga]/([Ga] + [In]) (GGI) grading. It is shown that photon scattering due to the Mo NP contributes to an absolute increase in short circuit current density of 3.4 mA/cm2; as compared to equivalent CIGS solar cells with a standard back contact.
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improved Rear Surface passivation of cu in ga se _ bf 2 solar cells a combination of an al _ bf 2 o _ bf 3 Rear Surface passivation layer and nanosized local Rear point contacts
IEEE Journal of Photovoltaics, 2014Co-Authors: Bart Vermang, Viktor Fjallstrom, Marika EdoffAbstract:An innovative Rear contacting structure for copper indium gallium (di) selenide (CIGS) thin-film solar cells is developed in an industrially viable way and demonstrated in tangible devices. The idea stems from the silicon (Si) industry, where Rear Surface passivation layers are combined with micron-sized local point contacts to boost the open-circuit voltage (VOC) and, hence, cell efficiency. However, compared with Si solar cells, CIGS solar cell minority carrier diffusion lengths are several orders lower in magnitude. Therefore, the proposed CIGS cell design reduces Rear Surface recombination by combining a Rear Surface passivation layer and nanosized local point contacts. Atomic layer deposition of Al2O3 is used to passivate the CIGS Surface and the formation of nanosphere-shaped precipitates in chemical bath deposition of CdS to generate nanosized point contact openings. The manufactured Al2O3 Rear Surface passivated CIGS solar cells with nanosized local Rear point contacts show a significant improvement in VOC compared with unpassivated reference cells.
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development of Rear Surface passivated cu in ga se2 thin film solar cells with nano sized local Rear point contacts
Solar Energy Materials and Solar Cells, 2013Co-Authors: Bart Vermang, Viktor Fjallstrom, Jonas Pettersson, P M P Salome, Marika EdoffAbstract:For the first time, a novel Rear contacting structure for copper indium gallium (di)selenide (CIGS) thin film solar cells is discussed theoretically, developed in an industrially viable way, and demonstrated in tangible devices. The proposed cell design reduces back contacting area by combining a Rear Surface passivation layer and nano-sized local point contacts. Atomic layer deposition (ALD) of Al2O3 is used to passivate the CIGS Surface and the formation of nano-sphere shaped precipitates in chemical bath deposition (CBD) of CdS to generate point contact openings. The Al2O3 Rear Surface passivated CIGS solar cells with nano-sized local Rear point contacts show a significant improvement in open circuit voltage (VOC) compared to unpassivated reference cells. Comparing the passivated devices to solar cell capacitance simulator (SCAPS) modeling indicates that this increase is attributed to a decrease in Rear Surface recombination of a few orders.
Martin A Green - One of the best experts on this subject based on the ideXlab platform.
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enhanced light trapping for high efficiency crystalline solar cells by the application of Rear Surface plasmons
Solar Energy Materials and Solar Cells, 2012Co-Authors: Y Yang, Supriya Pillai, Hamid Mehrvarz, Henner Kampwerth, Anita Hobaillie, Martin A GreenAbstract:Abstract In this article, a novel Rear structure using Ag nanoparticles to create Surface plasmons to enhance light trapping is applied on the Rear of planar high efficiency PERT (Passivated Emitter and Rear Totally Diffused) silicon wafer cells, targeting the spectrum range from 1000 nm to 1200 nm. Variations of this Rear structure that combine Ag nanoparticles, dielectric layers and back metal reflectors were studied and analysed. Thickness of the Rear Surface passivation SiO 2 spacer layer was optimised to achieve maximum optical enhancement using Surface plasmons but with minimum electronic losses due to recombination effects. The effect of the precursor evaporated Ag film thickness was also studied as a means to vary the size/shape of the nanoparticles. The measured external quantum efficiency ( EQE ) of the best performing Rear reflector shows a maximum enhancement of more than 4-fold at 1160 nm. This corresponds to a 16% photocurrent increase (calculated from 900 nm to 1200 nm) compared to the cell with conventional Al Rear reflector. Moreover, from the measured spectral response and optical absorption data, we successfully separated and analysed the electrical and optical properties of the novel Rear light trapping designs. Light trapping features were quantified using optical parameters characterised by an effective optical path length factor Z , while electrical parameters such as Surface recombination velocity S (cm/s) and effective minority charge carrier lifetime τ bulk (μs) were also extracted. Relative errors for these parameters were also calculated. For the cell with the best performing Rear structure, we report a maximum Z factor enhancement of around 6-fold using Ag nanoparticles in conjunction with a detached Ag reflector, in comparison to the reference at 1200 nm.
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efficiency enhancement of solar cells by luminescent up conversion of sunlight
Solar Energy Materials and Solar Cells, 2006Co-Authors: Thorsten Trupke, Avi Shalav, Bryce S Richards, Peter Wurfel, Martin A GreenAbstract:Significant improvements in the efficiency of solar cells by combination with luminescent up- or down-converters have recently been predicted theoretically. Here, we extend the theoretical analysis of the limiting efficiency of the up-conversion (UC)-system to realistic Airmass spectra and analyse the spectral robustness of the UC-system. We also present initial experimental results from prototypes involving bifacial silicon solar cells with UC-phosphors attached to the Rear Surface, and discuss the possibility of realizing efficient UC with low-band-gap solar cells in combination with a light emitting diode.
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high efficiency silicon solar cells full factor limitations and non ideal diode behaviour due to voltage dependent Rear Surface recombination velocity
Progress in Photovoltaics, 1993Co-Authors: Armin G Aberle, S R Wenham, Aihua Wang, Jianhua Zhao, Stephen J Robinson, Martin A GreenAbstract:Despite exceptionally high open-circuit voltages, record high-efficiency PERL (passivated emitter, Rear locally diffused) silicon solar cells recently developed at the University of New South Wales demonstrate relatively low fill factors. This behaviour is shown to result from a Surface recombination velocity at the Rear Si-SiO2 interface that increases with reducing voltage across the cell, leading to non-ideal I-V curves with high ideality factors (>1.3) near the maximum power point. When corrected for series resistance losses, the Air Mass 1.5 (AM1.5) fill factor of actual PERL cells is found to be limited to values below 82.9%, as opposed to the ideal theoretical limit of 85-86% for silicon cells operating in low injection conditions. Relatively large series resistance losses (Rs > 0.35 ω cm2) further reduce this value to the experimentally observed fill factors below 81.4%. Analysis of measured illuminated and dark I-V characteristics of PERL cells reveals that the AM1.5 efficiency is mainly limited by recombination losses at the Rear oxidized Surface. Optimum PERL cell resistivity is about 2 ω cm. Owing to increased Rear Surface recombination velocity, lower resistivity material shows no advantage in open-circuit voltage and suffers from short-circuit current losses, while a strong reduction in the Surface recombination velocity above the maximum power point results in smaller fill factors. High-resistivity cells do show an improved short-cuircuit current but suffer from voltage and fill factor losses.
J John - One of the best experts on this subject based on the ideXlab platform.
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approach for al2o3 Rear Surface passivation of industrial p type si perc above 19
Progress in Photovoltaics, 2012Co-Authors: Bart Vermang, Hans Goverde, Loic Tous, A Lorenz, Patrick Choulat, Jorg Horzel, J JohnAbstract:Atomic layer deposition (ALD) of thin Al2O3 (≤10 nm) films is used to improve the Rear Surface passivation of large-area screen-printed p-type Si passivated emitter and Rear cells (PERC). A blister-free stack of Al2O3/SiOx/SiNx is developed, leading to an improved back reflection and a Rear recombination current (J0,Rear) of 92 ± 6 fA/cm2. The Al2O3/SiOx/SiNx stack is blister-free if a 700°C anneal in N2 is performed after the Al2O3 deposition and prior to the SiOx/SiNx capping. A clear relationship between blistering density and lower open-circuit voltage (VOC) due to increased Rear contacting area is shown. In case of the blister-free Al2O3/SiOx/SiNx Rear Surface passivation stack, an average cell efficiency of 19.0% is reached and independently confirmed by FhG-ISE CalLab. Compared with SiOx/SiNx-passivated PERC, there is an obvious gain in VOC and short-circuit current (JSC) of 5 mV and 0.2 mA/cm2, respectively, thanks to improved Rear Surface passivation and Rear internal reflection. Copyright © 2012 John Wiley & Sons, Ltd.
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approach for al2o3 Rear Surface passivation of industrial p type si perc above 19
Progress in Photovoltaics, 2012Co-Authors: Bart Vermang, Hans Goverde, Loic Tous, A Lorenz, Patrick Choulat, Jorg Horzel, J JohnAbstract:Atomic layer deposition (ALD) of thin Al2O3 (≤10 nm) films is used to improve the Rear Surface passivation of large-area screen-printed p-type Si passivated emitter and Rear cells (PERC). A blister-free stack of Al2O3/SiOx/SiNx is developed, leading to an improved back reflection and a Rear recombination current (J0,Rear) of 92 ± 6 fA/cm2. The Al2O3/SiOx/SiNx stack is blister-free if a 700°C anneal in N2 is performed after the Al2O3 deposition and prior to the SiOx/SiNx capping. A clear relationship between blistering density and lower open-circuit voltage (VOC) due to increased Rear contacting area is shown. In case of the blister-free Al2O3/SiOx/SiNx Rear Surface passivation stack, an average cell efficiency of 19.0% is reached and independently confirmed by FhG-ISE CalLab. Compared with SiOx/SiNx-passivated PERC, there is an obvious gain in VOC and short-circuit current (JSC) of 5 mV and 0.2 mA/cm2, respectively, thanks to improved Rear Surface passivation and Rear internal reflection. Copyright © 2012 John Wiley & Sons, Ltd.
