Concentrator Multijunction Solar Cells

Rey‐Stolle, Ignacio; Olson, J. M.; Algora, Carlos

doi:10.1002/9781118755655.ch02

Cited by 15 publications

(12 citation statements)

References 133 publications

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“…In these devices, which lack an antireflection coating, there is a ~4% difference between the top GaInP subcell and the middle Ga(In)As subcell short circuit currents. It is known that current mismatch can lead to artificially high fill factors, so in order to quantify how much of the high FF measured can be attributed to a highly conductive grid and how much is the result of current mismatch, we decided to simulate the FF of solar cells with top and middle cells perfectly current matched. These are plotted as dashed lines in the FF curve in Figure .…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, the struggle against series resistance is one of the most important factors when tackling the optimization of solar cell performance, especially in the ultra‐high concentration realm (>1000 suns). In a multijunction solar cell, the series resistance mainly stems from (a) the metal grid sheet resistance ( R M‐sheet ) and the metal/semiconductor specific contact resistance of the front metallization ( R C ); (b) the top cell window and emitter sheet resistance ( R E‐sheet ); and (c) the vertical resistance across the solar cell ( R V ) including that of barriers formed at heterojunctions and tunnel junctions . Among them, components (b) and (c) are related to the semiconductor structure of the multijunction solar cell and are therefore impacted by other compromises and trade‐offs typically aiming at maximizing carrier collection.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced performance of GaInP/GaAs/Ge solar cells under high concentration through Pd/Ge/Ti/Pd/Al grid metallization

Huo

Lombardero

García

2019

Progress in Photovoltaics

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Series resistance is the key limiting factor that constrains the electrical performance of solar cells under ultra‐high concentration. Typically, the most critical component of the series resistance is that stemming from the front contact, and therefore, the formation of front metal grids with low metal–semiconductor specific contact resistance and low metal sheet resistance is vital for high concentrator solar cells. Consequently, in this study, a novel Pd/Ge/Ti/Pd/Al metal stack has been proposed and implemented on a GaInP/GaAs/Ge triple junction solar cell. This system exhibits low metal resistivity due to the middle Ti/Pd barrier layer hindering the diffusion and contamination between the GaAs semiconductor and top conductive metal layer, and very low specific contact resistance because of the Pd/Ge layer forming an interfacial layer with the GaAs cap which increases the electron tunneling probability. As a result, the fill factor of the solar cell remains almost constant and close to 90% in the 250× to 1500× range, while efficiency keeps on increasing even at the maximum concentration measured of 1500×. Its performance and cost‐effectiveness make this contact a compelling solution to extend solar cell operation in the ultra‐high concentration regime.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Enhanced performance of GaInP/GaAs/Ge solar cells under high concentration through Pd/Ge/Ti/Pd/Al grid metallization

Huo

Lombardero

García

2019

Progress in Photovoltaics

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“…Then the company applied the InGaP/GaAs/Ge triple junction solar cell into high concentrated photovoltaic power system, the results shows that the efficiency is up to 41.6%. Besides, GaInP/InGaAs/InGaNAs/Ge four-junction solar cell has been produced by the utilisation of epitaxial growth technology, which expresses the highest conversion efficiency in the world [41].…”

Section: Multi-junction Solar Cellmentioning

confidence: 99%

A Review on Recent Development of Cooling Technologies for Concentrated Photovoltaics (CPV) Systems

et al. 2018

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Concentrated Photovoltaics (CPV) technology, as an energy saving method which can directly generate electricity from the Sun, has attracted an ever-increasing attention with the deepening worldwide energy crisis. However, operating temperature is one of the main concerns that affect the CPV system. Excess cell temperature causes electrical conversion efficiency loss and cell lifespan decrease. Thus, reasonable cooling methods should decrease the operating temperature and balance the flare inhomogeneity. They also need to display high reliability, low power consumption, and convenient installation. This paper presented the architectural, commercial, and industrial usage of CPV system, reviewed the recent research developments of different cooling techniques of CPV systems during last few years, including the spectral beam splitting technology, cogeneration power technology, commonly used and promising cooling techniques, active and passive cooling methods. It also analysed the design considerations of the cooling methods in CPV systems, introduced the classification and basic working principles and provided a thorough compilation of different cooling techniques with their advantages, current research limitations, challenges, and possible further research directions. The aim of this work is to find the research gap and recommend feasible research direction of cooling technologies for CPV systems.

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“…[1] These devices are manufactured monolithically and consist of series-connected subcells of different materials, using tunnel diodes as interconnects between subcells. The workhorse of this technology is the GaInP/Ga(In)As/Ge triple-junction solar cell, [2] with AlGaInP/AlGaInAs/Ga(In)As/Ge four-junction upright metamorphic starting to reach the market and other designs based on inverted metamorphic growth (IMM) being used in limited applications. [3,4] One common problem faced by these devices is the degradation related to the operation under reverse bias.…”

Section: Introductionmentioning

confidence: 99%

“…The complete response of the multijunction device is obtained by the series connection of the subcells with the tunnel diodes being modelled by an additional contribution to the series resistance. [2] Likewise, to model the reverse behavior of the devices and given the moderate dopant concentrations used in the base of the three subcells, we assume that the breakdown region of the solar cell is dominated by avalanche multiplication and, to account for this effect, we have followed the model proposed by Spirito and Albergamo (also referred to as S-A model in this work). [9] This approach considers that under reverse bias the primary currents of Equation (1) are multiplied by a certain multiplication factor M(V):…”

mentioning

confidence: 99%

Study of the reverse I–V in component subcells of III–V multijunction space solar cells

Martín

González

García

et al. 2021

Progress in Photovoltaics

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The reverse bias operation of triple-junction solar cells (GaInP/Ga(In)As/Ge), typically used for space photovoltaics, is poorly understood. In this work, we conduct reverse bias stress tests on both isotype subcells (GaInP, Ga(In)As and Ge) as well as in the complete triplejunction solar cell. After each reverse bias step, forward dark and lighted I-Vs are measured and modelled using Shockley and Spirito and Albergamo models to fit the characteristic parameters of each individual subcell and quantify the variations evolution caused by the stress. The changes in these parameters are thoroughly analyzed in order to comprehend the basic physical processes behind the degradation observed after the reverse bias is applied.Finally, we demonstrate that the individual parameters obtained from each subcell can be combined to simulate the final I-V curve of the complete triple junction and understand how it is affected when reverse bias is applied, linking the changes observed to a sudden degradation of the GaInP top subcell at low reverse voltages.

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Concentrator Multijunction Solar Cells

Cited by 15 publications

References 133 publications

Enhanced performance of GaInP/GaAs/Ge solar cells under high concentration through Pd/Ge/Ti/Pd/Al grid metallization

Enhanced performance of GaInP/GaAs/Ge solar cells under high concentration through Pd/Ge/Ti/Pd/Al grid metallization

A Review on Recent Development of Cooling Technologies for Concentrated Photovoltaics (CPV) Systems

Study of the reverse I–V in component subcells of III–V multijunction space solar cells

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