1.
M Rienäcker; E L Warren; M Schnabel; H Schulte-Huxel; R Niepelt; R Brendel; P Stradins; A C Tamboli; R Peibst
In: Progress in Photovoltaics: Research and Applications, Bd. 27, Nr. 5, S. 410-423, 2019.
@article{Rienäcker2019,
title = {Back-contacted bottom cells with three terminals: Maximizing power extraction from current-mismatched tandem cells},
author = {M Rienäcker and E L Warren and M Schnabel and H Schulte-Huxel and R Niepelt and R Brendel and P Stradins and A C Tamboli and R Peibst},
doi = {10.1002/pip.3107},
year = {2019},
date = {2019-05-01},
journal = {Progress in Photovoltaics: Research and Applications},
volume = {27},
number = {5},
pages = {410-423},
abstract = {Abstract 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.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract 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.
2.
M Schnabel; H Schulte-Huxel; T R Klein; M Rienaecker; J F Giesz; B G Lee; R Niepelt; S Kajari-Schroeder; M. F. A. M. Hest; E L Warren; R Brendel; R Peibst; P Stradins; A C Tamboli
Three-Terminal III-V/Si Tandem Solar Cells Fabricated Using a Transparent, Conductive Adhesive Vortrag
Waikoloa, HI, USA, 15.06.2018, (2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC)).
@misc{Schnabel2018,
title = {Three-Terminal III-V/Si Tandem Solar Cells Fabricated Using a Transparent, Conductive Adhesive},
author = {M Schnabel and H Schulte-Huxel and T R Klein and M Rienaecker and J F Giesz and B G Lee and R Niepelt and S Kajari-Schroeder and M. F. A. M. Hest and E L Warren and R Brendel and R Peibst and P Stradins and A C Tamboli},
editor = {IEEE},
year = {2018},
date = {2018-06-15},
booktitle = {7th World Conference on Photovoltaic Energy Conversion (WCPEC-7)},
address = {Waikoloa, HI, USA},
abstract = {Multijunction architectures provide a crosscutting solution for increasing solar cell efficiency for a variety of material types and combinations. We discuss a three-terminal tandem cell demonstrated using a III-V/Si platform. High efficiencies have been achieved in two and four terminal designs, but two-terminal cells require current matching, and four-terminal cells require intermediate grids to transport current laterally from in between the cells to the edges, which can lead to optical and resistive losses. Our three-terminal architecture utilizes a modified interdigitated back contact Si bottom cell, enabling maximized power extraction for any band gap combination, without intermediate grids. We demonstrate a >25% efficient GaInP/Si 3T cell which is bonded using a transparent, conductive adhesive material to enable optical and electrical coupling between the subcells.},
note = {2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC)},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Multijunction architectures provide a crosscutting solution for increasing solar cell efficiency for a variety of material types and combinations. We discuss a three-terminal tandem cell demonstrated using a III-V/Si platform. High efficiencies have been achieved in two and four terminal designs, but two-terminal cells require current matching, and four-terminal cells require intermediate grids to transport current laterally from in between the cells to the edges, which can lead to optical and resistive losses. Our three-terminal architecture utilizes a modified interdigitated back contact Si bottom cell, enabling maximized power extraction for any band gap combination, without intermediate grids. We demonstrate a >25% efficient GaInP/Si 3T cell which is bonded using a transparent, conductive adhesive material to enable optical and electrical coupling between the subcells.