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Title: Hybrid Tandem Photovoltaics

Abstract

Tandem solar cell structures are the only strategy demonstrated to surpass the detailed balance efficiency limit of high-quality single-junction solar cells. To continue to improve the efficiencies of cost-effective terrestrial solar power, hybrid tandems of dissimilar subcells are being considered by many around the world, especially designs that incorporate silicon solar cells as a bottom subcell. In this project, we studied a wide variety of tandem design possibilities including those with three-terminal (3T) and four-terminal (4T) configurations. The use of 3T and 4T designs could be useful for efficient and economical hybrid tandem designs that utilize the best available subcell materials such as emerging perovskite materials. Three-terminal configurations, in particular, have not been sufficiently studied previously. We have laid the foundational groundwork in this project for understanding the operation of 3T tandems: developing a taxonomy for naming, a methodology for measuring and interconnecting, and models for simply characterizing 3T tandems. Electrical and optical subcell coupling between the subcells was also measured and modeled. An important part of this work was the fabrication of novel example tandem structures, including 4T GaAs/Si, 3T GaInP/Si, 3T GaAs/Si, and 3T GaInP/GaAs devices. Using these high-quality tandem cells, we have been able to clearly demonstratemore » the achievability of high-efficiencies, and subtle physical effects such as photon recycling and luminescent coupling. We have developed and demonstrated essential building-block tools such as transparent conductive adhesives (TCA) and 3T silicon bottom cells with interdigitated back contacts (IBC) that can also be used in many other tandem designs. We have tested the reliability of these tools and devices under standardized testing and outdoor measurements. We have found 4T GaAs/Si tandems to be relatively straightforward to fabricate and robust in real-world outdoor conditions. While we have demonstrated working hybrid 3T III-V/TCA/Si IBC tandems, we experienced low yields even with our best process flows yet. Further work is still needed to improve the processing yield of these devices. We therefore also created tandem cells using an all-III-V 3T tandem process which was very robust with high yields, allowing for the creation of voltage-matched strings in many different configurations using 8 nearly identical 3T tandems. Using these robust 3T tandem examples, we were able measure and precisely characterize 3T tandem behaviors to predict their operation under changing spectrum and temperature. The optoelectronic equivalent-circuit model was shown to be very general and applicable to hybrid tandems, and encompassed the operation 3T Si IBC cells. This general model has been distributed to the public in as open-source Python-based software called PVcircuit. We have calculated the implications of these new tandem device designs on the real-world energy production and shown how the relative performance of different tandem configurations is situational and can be engineered using the tools developed here.« less

Authors:
ORCiD logo [1]; ORCiD logo [1];  [1];  [1];  [1]; ORCiD logo [1];  [1];  [2];  [1];  [1];  [1];  [1]
  1. National Renewable Energy Laboratory (NREL), Golden, CO (United States)
  2. National Renewable Energy Laboratory (NREL), Golden, CO (United States); Colorado School of Mines, Golden, CO (United States)
Publication Date:
Research Org.:
National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
OSTI Identifier:
1963068
Report Number(s):
NREL/TP-5900-84173
MainId:84946;UUID:98ed9f6d-ae43-4d5e-a11a-09ecf8b68aea;MainAdminID:67750
DOE Contract Number:  
AC36-08GO28308
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 14 SOLAR ENERGY; hybrid; tandem; three-terminal

Citation Formats

Warren, Emily, Geisz, John, Buencuerpo, Jeronimo, Klein, Talysa, McMahon, Bill, Silverman, Tim, Stradins, Paul, VanSant, Kaitlyn, Young, Michelle, Whitehead, Riley, Wilson, Mickey, and Tamboli, Adele. Hybrid Tandem Photovoltaics. United States: N. p., 2023. Web. doi:10.2172/1963068.
Warren, Emily, Geisz, John, Buencuerpo, Jeronimo, Klein, Talysa, McMahon, Bill, Silverman, Tim, Stradins, Paul, VanSant, Kaitlyn, Young, Michelle, Whitehead, Riley, Wilson, Mickey, & Tamboli, Adele. Hybrid Tandem Photovoltaics. United States. https://doi.org/10.2172/1963068
Warren, Emily, Geisz, John, Buencuerpo, Jeronimo, Klein, Talysa, McMahon, Bill, Silverman, Tim, Stradins, Paul, VanSant, Kaitlyn, Young, Michelle, Whitehead, Riley, Wilson, Mickey, and Tamboli, Adele. 2023. "Hybrid Tandem Photovoltaics". United States. https://doi.org/10.2172/1963068. https://www.osti.gov/servlets/purl/1963068.
@article{osti_1963068,
title = {Hybrid Tandem Photovoltaics},
author = {Warren, Emily and Geisz, John and Buencuerpo, Jeronimo and Klein, Talysa and McMahon, Bill and Silverman, Tim and Stradins, Paul and VanSant, Kaitlyn and Young, Michelle and Whitehead, Riley and Wilson, Mickey and Tamboli, Adele},
abstractNote = {Tandem solar cell structures are the only strategy demonstrated to surpass the detailed balance efficiency limit of high-quality single-junction solar cells. To continue to improve the efficiencies of cost-effective terrestrial solar power, hybrid tandems of dissimilar subcells are being considered by many around the world, especially designs that incorporate silicon solar cells as a bottom subcell. In this project, we studied a wide variety of tandem design possibilities including those with three-terminal (3T) and four-terminal (4T) configurations. The use of 3T and 4T designs could be useful for efficient and economical hybrid tandem designs that utilize the best available subcell materials such as emerging perovskite materials. Three-terminal configurations, in particular, have not been sufficiently studied previously. We have laid the foundational groundwork in this project for understanding the operation of 3T tandems: developing a taxonomy for naming, a methodology for measuring and interconnecting, and models for simply characterizing 3T tandems. Electrical and optical subcell coupling between the subcells was also measured and modeled. An important part of this work was the fabrication of novel example tandem structures, including 4T GaAs/Si, 3T GaInP/Si, 3T GaAs/Si, and 3T GaInP/GaAs devices. Using these high-quality tandem cells, we have been able to clearly demonstrate the achievability of high-efficiencies, and subtle physical effects such as photon recycling and luminescent coupling. We have developed and demonstrated essential building-block tools such as transparent conductive adhesives (TCA) and 3T silicon bottom cells with interdigitated back contacts (IBC) that can also be used in many other tandem designs. We have tested the reliability of these tools and devices under standardized testing and outdoor measurements. We have found 4T GaAs/Si tandems to be relatively straightforward to fabricate and robust in real-world outdoor conditions. While we have demonstrated working hybrid 3T III-V/TCA/Si IBC tandems, we experienced low yields even with our best process flows yet. Further work is still needed to improve the processing yield of these devices. We therefore also created tandem cells using an all-III-V 3T tandem process which was very robust with high yields, allowing for the creation of voltage-matched strings in many different configurations using 8 nearly identical 3T tandems. Using these robust 3T tandem examples, we were able measure and precisely characterize 3T tandem behaviors to predict their operation under changing spectrum and temperature. The optoelectronic equivalent-circuit model was shown to be very general and applicable to hybrid tandems, and encompassed the operation 3T Si IBC cells. This general model has been distributed to the public in as open-source Python-based software called PVcircuit. We have calculated the implications of these new tandem device designs on the real-world energy production and shown how the relative performance of different tandem configurations is situational and can be engineered using the tools developed here.},
doi = {10.2172/1963068},
url = {https://www.osti.gov/biblio/1963068}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2023},
month = {Wed Mar 01 00:00:00 EST 2023}
}