Monolithic thin-film chalcogenide–silicon tandem solar cells enabled by a diffusion barrier

Alireza Hajijafarassar*, Filipe Mesquita Alves Martinho, Fredrik Stulen, Sigbjørn Grini, Simón López Mariño, Moises Espindola Rodriguez, Max Döbeli, Stela Canulescu, Eugen Stamate, Mungunshagai Gansukh, Sara Lena Josefin Engberg, Andrea Crovetto, Lasse Vines, Jørgen Schou, Ole Hansen

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Following the recent success of monolithically integrated Perovskite/Si tandem solar cells, great interest has been raised in searching for alternative wide bandgap top-cell materials with prospects of a fully earth-abundant, stable and efficient tandem solar cell. Thin film chalcogenides (TFCs) such as the Cu2ZnSnS4 (CZTS) could be suitable top-cell materials. However, TFCs have the disadvantage that generally at least one high temperature step (>500 °C) is needed during the synthesis, which could contaminate the Si bottom cell. Here, we systematically investigate the monolithic integration of CZTS on a Si bottom solar cell. A thermally resilient double-sided Tunnel Oxide Passivated Contact (TOPCon) structure is used as bottom cell. A thin (<25 nm) TiN layer between the top and bottom cells, doubles as diffusion barrier and recombination layer. We show that TiN successfully mitigates in-diffusion of CZTS elements into the c-Si bulk during the high temperature sulfurization process, and find no evidence of electrically active deep Si bulk defects in samples protected by just 10 nm TiN. Post-process minority carrier lifetime in Si exceeded 1.5 ms, i.e., a promising implied open-circuit voltage (i-Voc) of 715 mV after the high temperature sulfurization. Based on these results, we demonstrate a first proof-of-concept two-terminal CZTS/Si tandem device with an efficiency of 1.1% and a Voc of 900 mV. A general implication of this study is that the growth of complex semiconductors on Si using high temperature steps is technically feasible, and can potentially lead to efficient monolithically integrated two-terminal tandem solar cells.
Original languageEnglish
Article number110334
JournalSolar Energy Materials and Solar Cells
Volume207
Number of pages11
ISSN0927-0248
DOIs
Publication statusPublished - 2020

Keywords

  • Tandem
  • Photovoltaric
  • Silicon
  • TOPCon
  • CZTS
  • Titanium nitride

Cite this

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title = "Monolithic thin-film chalcogenide–silicon tandem solar cells enabled by a diffusion barrier",
abstract = "Following the recent success of monolithically integrated Perovskite/Si tandem solar cells, great interest has been raised in searching for alternative wide bandgap top-cell materials with prospects of a fully earth-abundant, stable and efficient tandem solar cell. Thin film chalcogenides (TFCs) such as the Cu2ZnSnS4 (CZTS) could be suitable top-cell materials. However, TFCs have the disadvantage that generally at least one high temperature step (>500 °C) is needed during the synthesis, which could contaminate the Si bottom cell. Here, we systematically investigate the monolithic integration of CZTS on a Si bottom solar cell. A thermally resilient double-sided Tunnel Oxide Passivated Contact (TOPCon) structure is used as bottom cell. A thin (<25 nm) TiN layer between the top and bottom cells, doubles as diffusion barrier and recombination layer. We show that TiN successfully mitigates in-diffusion of CZTS elements into the c-Si bulk during the high temperature sulfurization process, and find no evidence of electrically active deep Si bulk defects in samples protected by just 10 nm TiN. Post-process minority carrier lifetime in Si exceeded 1.5 ms, i.e., a promising implied open-circuit voltage (i-Voc) of 715 mV after the high temperature sulfurization. Based on these results, we demonstrate a first proof-of-concept two-terminal CZTS/Si tandem device with an efficiency of 1.1{\%} and a Voc of 900 mV. A general implication of this study is that the growth of complex semiconductors on Si using high temperature steps is technically feasible, and can potentially lead to efficient monolithically integrated two-terminal tandem solar cells.",
keywords = "Tandem, Photovoltaric, Silicon, TOPCon, CZTS, Titanium nitride",
author = "Alireza Hajijafarassar and Martinho, {Filipe Mesquita Alves} and Fredrik Stulen and Sigbj{\o}rn Grini and Mari{\~n}o, {Sim{\'o}n L{\'o}pez} and {Espindola Rodriguez}, Moises and Max D{\"o}beli and Stela Canulescu and Eugen Stamate and Mungunshagai Gansukh and Engberg, {Sara Lena Josefin} and Andrea Crovetto and Lasse Vines and J{\o}rgen Schou and Ole Hansen",
year = "2020",
doi = "10.1016/j.solmat.2019.110334",
language = "English",
volume = "207",
journal = "Solar Energy Materials & Solar Cells",
issn = "0927-0248",
publisher = "Elsevier",

}

Monolithic thin-film chalcogenide–silicon tandem solar cells enabled by a diffusion barrier. / Hajijafarassar, Alireza; Martinho, Filipe Mesquita Alves; Stulen, Fredrik; Grini, Sigbjørn; Mariño, Simón López; Espindola Rodriguez, Moises; Döbeli, Max; Canulescu, Stela; Stamate, Eugen; Gansukh, Mungunshagai; Engberg, Sara Lena Josefin; Crovetto, Andrea; Vines, Lasse; Schou, Jørgen; Hansen, Ole.

In: Solar Energy Materials and Solar Cells, Vol. 207, 110334, 2020.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Monolithic thin-film chalcogenide–silicon tandem solar cells enabled by a diffusion barrier

AU - Hajijafarassar, Alireza

AU - Martinho, Filipe Mesquita Alves

AU - Stulen, Fredrik

AU - Grini, Sigbjørn

AU - Mariño, Simón López

AU - Espindola Rodriguez, Moises

AU - Döbeli, Max

AU - Canulescu, Stela

AU - Stamate, Eugen

AU - Gansukh, Mungunshagai

AU - Engberg, Sara Lena Josefin

AU - Crovetto, Andrea

AU - Vines, Lasse

AU - Schou, Jørgen

AU - Hansen, Ole

PY - 2020

Y1 - 2020

N2 - Following the recent success of monolithically integrated Perovskite/Si tandem solar cells, great interest has been raised in searching for alternative wide bandgap top-cell materials with prospects of a fully earth-abundant, stable and efficient tandem solar cell. Thin film chalcogenides (TFCs) such as the Cu2ZnSnS4 (CZTS) could be suitable top-cell materials. However, TFCs have the disadvantage that generally at least one high temperature step (>500 °C) is needed during the synthesis, which could contaminate the Si bottom cell. Here, we systematically investigate the monolithic integration of CZTS on a Si bottom solar cell. A thermally resilient double-sided Tunnel Oxide Passivated Contact (TOPCon) structure is used as bottom cell. A thin (<25 nm) TiN layer between the top and bottom cells, doubles as diffusion barrier and recombination layer. We show that TiN successfully mitigates in-diffusion of CZTS elements into the c-Si bulk during the high temperature sulfurization process, and find no evidence of electrically active deep Si bulk defects in samples protected by just 10 nm TiN. Post-process minority carrier lifetime in Si exceeded 1.5 ms, i.e., a promising implied open-circuit voltage (i-Voc) of 715 mV after the high temperature sulfurization. Based on these results, we demonstrate a first proof-of-concept two-terminal CZTS/Si tandem device with an efficiency of 1.1% and a Voc of 900 mV. A general implication of this study is that the growth of complex semiconductors on Si using high temperature steps is technically feasible, and can potentially lead to efficient monolithically integrated two-terminal tandem solar cells.

AB - Following the recent success of monolithically integrated Perovskite/Si tandem solar cells, great interest has been raised in searching for alternative wide bandgap top-cell materials with prospects of a fully earth-abundant, stable and efficient tandem solar cell. Thin film chalcogenides (TFCs) such as the Cu2ZnSnS4 (CZTS) could be suitable top-cell materials. However, TFCs have the disadvantage that generally at least one high temperature step (>500 °C) is needed during the synthesis, which could contaminate the Si bottom cell. Here, we systematically investigate the monolithic integration of CZTS on a Si bottom solar cell. A thermally resilient double-sided Tunnel Oxide Passivated Contact (TOPCon) structure is used as bottom cell. A thin (<25 nm) TiN layer between the top and bottom cells, doubles as diffusion barrier and recombination layer. We show that TiN successfully mitigates in-diffusion of CZTS elements into the c-Si bulk during the high temperature sulfurization process, and find no evidence of electrically active deep Si bulk defects in samples protected by just 10 nm TiN. Post-process minority carrier lifetime in Si exceeded 1.5 ms, i.e., a promising implied open-circuit voltage (i-Voc) of 715 mV after the high temperature sulfurization. Based on these results, we demonstrate a first proof-of-concept two-terminal CZTS/Si tandem device with an efficiency of 1.1% and a Voc of 900 mV. A general implication of this study is that the growth of complex semiconductors on Si using high temperature steps is technically feasible, and can potentially lead to efficient monolithically integrated two-terminal tandem solar cells.

KW - Tandem

KW - Photovoltaric

KW - Silicon

KW - TOPCon

KW - CZTS

KW - Titanium nitride

U2 - 10.1016/j.solmat.2019.110334

DO - 10.1016/j.solmat.2019.110334

M3 - Journal article

VL - 207

JO - Solar Energy Materials & Solar Cells

JF - Solar Energy Materials & Solar Cells

SN - 0927-0248

M1 - 110334

ER -