A comparison of different module configurations for multi-band-gap solar cells

Gee, J.M.

doi:10.1016/0379-6787(88)90044-0

Cited by 65 publications

(50 citation statements)

References 4 publications

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“…The model introduced so far (with R IBC = 0 and R FB = 0) in Figure 6A is intuitive and therefore commonly used for mid-contacted 3T tandem solar cells, 25,28,34,35,39 as shown in Figure 6B,C (with R IBC = 0 and R FB = 0). The BJT solar cell, which has the same architecture as reported earlier by several authors, [25][26][27][28][29][30][31][32][33][34][35][36]41 was modeled by Martí and Luque using Ebers-Moll model 54 and turns out to be still describable by Figure 6C (without resistors).…”

Section: Equivalent Circuit Modelmentioning

confidence: 99%

“…A mid-contacted 3T tandem enables a monolithic tandem solar cell, which combines the monolithic design of 2T tandems and the flexibility of 4T tandem cells. Furthermore, Gee, 29,39 and Schulte-Huxel et al 40 studied module integration schemes for 3T tandem cells in voltage-matched 2T modules by means of simple equivalent circuit modeling and proved nearly loss-free integration and higher energy yields compared with seriesconnected 2T tandem cell modules. 17,20 However, fabricating the transparent and highly conductive middle electrode is challenging and can reduce device area.…”

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confidence: 99%

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Back‐contacted bottom cells with three terminals: Maximizing power extraction from current‐mismatched tandem cells

Rienäcker

Warren

Schnabel

et al. 2019

Progress in Photovoltaics

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Multi‐junction cells can significantly improve the energy yield of photovoltaic systems over a single‐junction cell. The internal interconnection scheme of the subcells is an important aspect in determining the resulting levelized cost of electricity. For a dual‐junction cell, two approaches are commonly discussed: series‐connected tandem cells with two terminals or independently working subcells in a four‐terminal (4T) tandem device. In this paper, we explore the working principle and the operation modes of a third, rarely discussed option: a three‐terminal (3T) tandem cell using a back‐contacted bottom cell with 3Ts. We use current–voltage measurements of illuminated 3T interdigitated back contact cells and confirm that the front and rear base contacts are at similar quasi‐Fermi level positions, which enables the bottom cell to either efficiently collect surplus carriers, in the case of a current‐limiting or carrier injecting top cell, or inject majority carriers, in the case of a current‐limiting bottom cell. As a result, no current matching is needed. The power output of an idealized 3T bottom cell without resistive effects is independent of the current density applied from the top cell. These characteristics of the 3T bottom cells enable a 3T tandem to operate as efficiently as a 4T tandem, while being compatible with monolithic design and not requiring intermediate grids. We propose a simple equivalent circuit model including additional resistive effects, which describes a real 3T bottom cell and achieves excellent agreement to the experiment. We deduce design guidelines for a 3T bottom cell in different operation regimes.

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Section: Equivalent Circuit Modelmentioning

confidence: 99%

mentioning

confidence: 99%

Back‐contacted bottom cells with three terminals: Maximizing power extraction from current‐mismatched tandem cells

Rienäcker

Warren

Schnabel

et al. 2019

Progress in Photovoltaics

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“…Traditionally, tandem solar cells have been fabricated in either 2- or 4-terminal configurations, 14 representing different extrema in the space of optical and electronic coupling. The 2-terminal (2-T) design is monolithic and requires series interconnected cells, while the 4-terminal (4-T) design is mechanically stacked and enables independently connected cells.…”

mentioning

confidence: 99%

Nanoscale Back Contact Perovskite Solar Cell Design for Improved Tandem Efficiency

2017

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Tandem photovoltaics, combining absorber layers with two distinct band gap energies into a single device, provide a practical solution to reduce thermalization losses in solar energy conversion. Traditionally, tandem devices have been assembled using two-terminal (2-T) or four-terminal (4-T) configurations; the 2-T limits the tandem performance due to the series connection requiring current matching, while the standard 4-T configuration requires at least three transparent electrical contacts, which reduce the total collected power due to unavoidable parasitic absorption. Here, we introduce a novel architecture based on a nanoscale back-contact for a thin-film top cell in a three terminal (3-T) configuration. Using coupled optical–electrical modeling, we optimize this architecture for a planar perovskite-silicon tandem, highlighting the roles of nanoscale contacts to reduce the required perovskite electronic quality. For example, with an 18% planar silicon base cell, the 3-T back contact design can reach a 32.9% tandem efficiency with a 10 μm diffusion length perovskite material. Using the same perovskite quality, the 4-T and 2-T configurations only reach 30.2% and 24.8%, respectively. We also confirm that the same 3-T efficiency advantage applies when using 25% efficient textured silicon base cells, where the tandems reach 35.2% and 32.8% efficiency for the 3-T, and 4-T configurations, respectively. Furthermore, because our design is based on the individual subcells being back-contacted, further improvements can be readily made by optimizing the front surface, which is left free for additional antireflective coating, light trapping, surface passivation, and photoluminescence outcoupling enhancements.

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“…However, in the case the structure is used to implement a solar cell, after the transistor effect should be avoided. A and B represent the two terminals of the module (adapted from Gee [11] ).…”

Section: Discussionmentioning

confidence: 99%

“…When cells exhibit several terminals, how to interconnect them at module level is a non-trivial problem. In particular, in the case of a three terminal solar cell, Gee [11] provided a solution for the cell interconnection which is illustrated in Figure 5.…”

Section: Implementation At Module Levelmentioning

confidence: 99%

Potential of the three-terminal heterojunction bipolar transistor solar cell for space applications

Martı́

García‐Linares

Zehender

et al. 2019

2019 European Space Power Conference (ESPC)

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The three terminal heterojunction bipolar transistor solar cell (3T-HBTSC) is characterized by a muti-junction solar cell structure that resembles that of a (npn or pnp) bipolar transistor. The top cell consists of the top np (pn) layers which are made of a high bandgap semiconductor. The bottom n(p) layer is made of a low bandgap semiconductor and, together with the middle p(n) layer, forms the bottom solar cell. The transistor structure allows some simplifications in the layer structure with respect to that of conventional multi-junction solar cells since, for example, tunnel junctions are not necessary. In spite of the name, in the 3T-HBTSC the transistor effect has to be avoided since, in the limit, this would result in the voltage of the top cell being limited by the voltage of the bottom cell.

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A comparison of different module configurations for multi-band-gap solar cells

Cited by 65 publications

References 4 publications

Back‐contacted bottom cells with three terminals: Maximizing power extraction from current‐mismatched tandem cells

Back‐contacted bottom cells with three terminals: Maximizing power extraction from current‐mismatched tandem cells

Nanoscale Back Contact Perovskite Solar Cell Design for Improved Tandem Efficiency

Potential of the three-terminal heterojunction bipolar transistor solar cell for space applications

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