Laser induced non-monotonic degradation in short-circuit current of triple-junction solar cells

In this study, a mechanical stacking technique has been used to bond together the GaInP/GaAs and poly-silicon (Si) solar wafers. A GaInP/GaAs/poly-Si triple-junction solar cell has mechanically stacked using a low-temperature bonding process which involves micro metal In balls on a metal line using a high-optical-transmission spin-coated glue material. Current–voltage measurements of the GaInP/GaAs/poly-Si triple-junction solar cells have carried out at room temperature both in the dark and under 1 sun with 100 mW/cm2 power density using a solar simulator. The GaInP/GaAs/poly-Si triple-junction solar cell has reached an efficiency of 24.5% with an open-circuit voltage of 2.68 V, a short-circuit current density of 12.39 mA/cm2, and a fill-factor of 73.8%. This study demonstrates a great potential for the low-temperature micro-metal-ball mechanical stacking technique to achieve high conversion efficiency for solar cells with three or more junctions.

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Damp-Heat Induced Performance Degradation for InGaP/GaAs/Ge Triple-Junction Solar Cell

Journal of Nanomaterials ◽

10.1155/2014/410717 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Hwen-Fen Hong ◽

Tsung-Shiew Huang ◽

Wu-Yih Uen ◽

Yen-Yeh Chen

Keyword(s):

Solar Cells ◽

Solar Cell ◽

Conversion Efficiency ◽

Triple Junction ◽

Fill Factor ◽

Open Circuit Voltage ◽

Short Circuit ◽

Short Circuit Current ◽

Energy Conversion Efficiency ◽

Open Circuit

We performed accelerated tests on sealed and nonsealed InGaP/InGaAs/Ge triple-junction (TJ) solar cells in a complex high temperature and high humidity environment and investigated the electrical properties over time. The degradation of energy conversion efficiency in nonsealed cells was found to be more serious than that in sealed cells. The short-circuit current (ISC), open-circuit voltage (VOC), and fill factor (FF) of sealed cells changed very slightly, though the conversion efficiency decreased 3.6% over 500 h of exposure. This decrease of conversion efficiency was suggested to be due to the deterioration of silicone encapsulant. TheISC,VOC, and FF of nonsealed cells decreased with increasing exposure time. By EL and SEM analysis, the root causes of degradation can be attributed to the damage and cracks near the edge of cells induced by the moisture ingress. It resulted in shunt paths that lead to a deterioration of the conversion efficiency of solar cell by increasing the leakage current, as well as decreasing open-circuit voltage and fill factor of nonsealed solar cells.

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Triple Junction n-i-p Solar Cells with Hot-Wire Deposited Protocrystalline and Microcrystalline Silicon

MRS Proceedings ◽

10.1557/proc-0989-a15-03 ◽

2007 ◽

Vol 989 ◽

Cited By ~ 6

Author(s):

Ruud E.I. Schropp ◽

Hongbo Li ◽

Ronald H.J. Franken ◽

Jatindra K. Rath ◽

Karine van der Werf ◽

...

Keyword(s):

Stainless Steel ◽

Solar Cells ◽

Current Density ◽

Triple Junction ◽

Short Circuit ◽

Short Circuit Current ◽

Hot Wire ◽

Single Junction ◽

Long Wavelength ◽

Back Reflector

AbstractWe have implemented a number of methods to improve the performance of proto-Si/proto-SiGe/μc-Si:H triple junction n-i-p solar cells in which the top and bottom cell i-layers are deposited by Hot-Wire CVD. Firstly, a significant current enhancement is obtained by using textured Ag/ZnO back contacts developed in house instead of plain stainless steel. We studied the correlation between the integrated current density in the long wavelength range (650-1000 nm) with the back reflector surface roughness and clarified that the rms roughness from 2D AFM images correlates well with the long wavelength response of the cell when weighted with a Power Spectral Density function. For single junction 2-μm thick μc-Si:H n-i-p cells we improved the short circuit current density from the value of 15.2 mA/cm2 for plain stainless steel to 23.4 mA/cm2 for stainless steel coated with a textured Ag/ZnO back reflector.Secondly, we optimized the μc-Si:H n-type doped layer on this rough back reflector, the n/i interface, and in addition used a profiling scheme for the H2/SiH4 ratio during i-layer deposition. The H2 dilution during growth was stepwise increased in order to prevent a transition to amorphous growth. The efficiency that was reached for a single junction μc-Si:H n-i-p cell was 8.5%, which is the highest reported value for hot-wire deposited cells of this kind, whereas the deposition rate of 2.1 Å/s is about twice as high as in record cells of this type so far. Moreover, these cells show to be totally stable under light-soaking tests.Combining the above techniques, a rather thin triple junction cell (total silicon thickness 2.5 μm) has been obtained with an efficiency of 10.9%. Preliminary light-soaking tests show that this type of triple cells degrades by less than 4%.

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Увеличение фототока Ga(In)As-субэлемента в многопереходных солнечных элементах GaInP/Ga(In)As/Ge

Письма в журнал технической физики ◽

10.21883/pjtf.2019.24.48802.17996 ◽

2019 ◽

Vol 45 (24) ◽

pp. 41

Author(s):

С.А. Минтаиров ◽

В.М. Емельянов ◽

Н.А. Калюжный ◽

М.З. Шварц ◽

В.М. Андреев

Keyword(s):

Solar Cells ◽

Potential Barrier ◽

Triple Junction ◽

Theoretical Study ◽

Short Circuit ◽

Spectral Characteristics ◽

Short Circuit Current ◽

Wide Bandgap ◽

Window Layer ◽

Wide Gap

An experimental and theoretical study of the spectral characteristics of the Ga(In)As subcell of the GaInP/Ga(In)As/Ge triple-junction solar cells has been carried out. It is shown that the use of a wide-gap “window” layer with an optimized thickness (Ga0.51In0.49P - 100 nm, Al0.4Ga0.6As - 110 nm, Al0.8Ga0.2As - 115 nm) for the Ga(In)As subcell allows increasing its photocurrent by about 0.5 mA/cm2, replacing the material of the back potential barrier of the GaInP subcell from Al0.53In0.47P to p+-Ga0.51In0.49P or AlGaAs allows increasing the short circuit current of Ga(In)As subcell by about 0.8 mA/cm2, and the use of the wide-bandgap Ga0.51In0.49P n++-layer in the tunnel diode instead of n++-GaAs increases the photocurrent by about 1 mA/cm2.

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Determining the exciton diffusion length of copper phthalocyanine in operating planar-heterojunction organic solar cells

The European Physical Journal Applied Physics ◽

10.1051/epjap/2020190322 ◽

2020 ◽

Vol 89 (3) ◽

pp. 30201 ◽

Cited By ~ 1

Author(s):

Xi Guan ◽

Shiyu Wang ◽

Wenxing Liu ◽

Dashan Qin ◽

Dayan Ban

Keyword(s):

Solar Cells ◽

Organic Solar Cells ◽

Diffusion Length ◽

Copper Phthalocyanine ◽

Short Circuit ◽

Thick Layer ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Exciton Diffusion ◽

Exciton Diffusion Length

Organic solar cells based on planar copper phthalocyanine (CuPc)/C60 heterojunction have been characterized, in which a 2 nm-thick layer of bathocuproine (BCP) is inserted into the CuPc layer. The thin layer of BCP allows hole current to tunnel it through but blocks the exciton diffusion, thereby altering the steady-state exciton profile in the CuPc zone (zone 1) sandwiched between BCP and C60. The short-circuit current density (JSC) of device is limited by the hole-exciton scattering effect at the BCP/CuPc (zone 1) interface. Based on the variation of JSC with the width of zone 1, the exciton diffusion length of CuPc is deduced to be 12.5–15 nm. The current research provides an easy and helpful method to determine the exciton diffusion lengths of organic electron donors.

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The Influence of the Thickness of Compact TiO2 Electron Transport Layer on the Performance of Planar CH3NH3PbI3 Perovskite Solar Cells

Materials ◽

10.3390/ma14123295 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3295

Author(s):

Andrzej Sławek ◽

Zbigniew Starowicz ◽

Marek Lipiński

Keyword(s):

Solar Cells ◽

Electron Transport ◽

Short Circuit ◽

Photovoltaic Performance ◽

Perovskite Solar Cells ◽

Precursor Solution ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Transport Layer ◽

Electron Transport Layer

In recent years, lead halide perovskites have attracted considerable attention from the scientific community due to their exceptional properties and fast-growing enhancement for solar energy harvesting efficiency. One of the fundamental aspects of the architecture of perovskite-based solar cells (PSCs) is the electron transport layer (ETL), which also acts as a barrier for holes. In this work, the influence of compact TiO2 ETL on the performance of planar heterojunction solar cells based on CH3NH3PbI3 perovskite was investigated. ETLs were deposited on fluorine-doped tin oxide (FTO) substrates from a titanium diisopropoxide bis(acetylacetonate) precursor solution using the spin-coating method with changing precursor concentration and centrifugation speed. It was found that the thickness and continuity of ETLs, investigated between 0 and 124 nm, strongly affect the photovoltaic performance of PSCs, in particular short-circuit current density (JSC). Optical and topographic properties of the compact TiO2 layers were investigated as well.

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CdTe-Based Thin Film Solar Cells: Past, Present and Future

Energies ◽

10.3390/en14061684 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1684

Author(s):

Alessandro Romeo ◽

Elisa Artegiani

Keyword(s):

Thin Film ◽

Solar Cells ◽

Solar Cell ◽

Short Circuit ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Open Circuit ◽

Early Years ◽

Solar Cell Efficiency ◽

Cell Efficiency

CdTe is a very robust and chemically stable material and for this reason its related solar cell thin film photovoltaic technology is now the only thin film technology in the first 10 top producers in the world. CdTe has an optimum band gap for the Schockley-Queisser limit and could deliver very high efficiencies as single junction device of more than 32%, with an open circuit voltage of 1 V and a short circuit current density exceeding 30 mA/cm2. CdTe solar cells were introduced at the beginning of the 70s and they have been studied and implemented particularly in the last 30 years. The strong improvement in efficiency in the last 5 years was obtained by a new redesign of the CdTe solar cell device reaching a single solar cell efficiency of 22.1% and a module efficiency of 19%. In this paper we describe the fabrication process following the history of the solar cell as it was developed in the early years up to the latest development and changes. Moreover the paper also presents future possible alternative absorbers and discusses the only apparently controversial environmental impacts of this fantastic technology.

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Ultrathin Cu(In,Ga)Se2 Solar Cells with Ag/AlOx Passivating Back Reflector

Energies ◽

10.3390/en14144268 ◽

2021 ◽

Vol 14 (14) ◽

pp. 4268

Author(s):

Jessica de Wild ◽

Gizem Birant ◽

Guy Brammertz ◽

Marc Meuris ◽

Jef Poortmans ◽

...

Keyword(s):

Surface Roughness ◽

Solar Cells ◽

Short Circuit ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Open Circuit ◽

Electron Microscopic ◽

Current Increase ◽

Time Resolved ◽

Cigs Solar Cells

Ultrathin Cu(In,Ga)Se2 (CIGS) absorber layers of 550 nm were grown on Ag/AlOx stacks. The addition of the stack resulted in solar cells with improved fill factor, open circuit voltage and short circuit current density. The efficiency was increased from 7% to almost 12%. Photoluminescence (PL) and time resolved PL were improved, which was attributed to the passivating properties of AlOx. A current increase of almost 2 mA/cm2 was measured, due to increased light scattering and surface roughness. With time of flight—secondary ion mass spectroscopy, the elemental profiles were measured. It was found that the Ag is incorporated through the whole CIGS layer. Secondary electron microscopic images of the Mo back revealed residuals of the Ag/AlOx stack, which was confirmed by energy dispersive X-ray spectroscopy measurements. It is assumed to induce the increased surface roughness and scattering properties. At the front, large stains are visible for the cells with the Ag/AlOx back contact. An ammonia sulfide etching step was therefore applied on the bare absorber improving the efficiency further to 11.7%. It shows the potential of utilizing an Ag/AlOx stack at the back to improve both electrical and optical properties of ultrathin CIGS solar cells.

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Improved Metal Oxide Electrode for CIGS Solar Cells: The Application of an AgOX Wetting Layer

Nanoscale Research Letters ◽

10.1186/s11671-021-03506-1 ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Nils Neugebohrn ◽

Norbert Osterthun ◽

Maximilian Götz-Köhler ◽

Kai Gehrke ◽

Carsten Agert

Keyword(s):

Thin Film ◽

Solar Cells ◽

Metal Oxide ◽

Metal Layer ◽

Short Circuit ◽

Short Circuit Current ◽

Thin Film Solar Cells ◽

Wetting Layer ◽

Transparent Conductive Oxides ◽

Effective Measure

AbstractOxide/metal/oxide (OMO) layer stacks are used to replace transparent conductive oxides as front contact of thin-film solar cells. These multilayer structures not only reduce the overall thickness of the contact, but can be used for colouring of the cells utilizing interference effects. However, sheet resistance and parasitic absorption, both of which depend heavily on the metal layer, should be further reduced to reach higher efficiencies in the solar cells. In this publication, AgOX wetting layers were applied to OMO electrodes to improve the performance of Cu(In,Ga)Se2 (CIGS) thin-film solar cells. We show that an AgOX wetting layer is an effective measure to increase transmission and conductivity of the multilayer electrode. With the presented approach, we were able to improve the short-circuit current density by 18% from 28.8 to 33.9 mA/cm2 with a metal (Ag) film thickness as low as 6 nm. Our results highlight that OMO electrodes can be an effective replacement for conventional transparent conductive oxides like aluminium-doped zinc oxide on thin-film solar cells.

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Improvement of Radiation Resistance of Multijunction GaInP/Ga(In)As/Ge Solar Cells with Application of Bragg Reflectors

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.74.225 ◽

2010 ◽

Vol 74 ◽

pp. 225-230 ◽

Cited By ~ 3

Author(s):

Vladimir M. Lantratov ◽

Viktor M. Emelyanov ◽

Nikolay A. Kalyuzhnyy ◽

Sergey A. Mintairov ◽

Maxim Z. Shvarts

Keyword(s):

Solar Cells ◽

Radiation Resistance ◽

Radiation Treatment ◽

Short Circuit ◽

Short Circuit Current ◽

Charge Carriers ◽

Bragg Reflectors ◽

Multijunction Solar Cells ◽

Operation Period ◽

Long Operation

Feasibility to increase the radiation resistance of multijunction solar cells in using Bragg reflectors has been shown. Two designs of Bragg reflectors for multijunction solar cells, which allow ensuring in the Ga(In)As subcell base an effective collection of minority charge carriers at the decrease of their diffusion length caused by radiation treatment, have been investigated. Influence of subcells’ thicknesses of n-p GaInP/Ga(In)As/Ge solar cell under 1 MeV electron irradiation with fluences up to 3•1015 cm–2 on short circuit current was considered. Optimal thicknesses of GaInP and GaInAs subcells with Bragg reflectors, depending on the rated operation period on the geostationary orbit, were estimated. It has been shown that such an optimization allows to achieve efficiency at long operation of solar cells on the orbit noticeably higher than that of non-optimized cells.

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