Control over Ligand Exchange Reactivity in Hole Transport Layer Enables High-Efficiency Colloidal Quantum Dot Solar Cells

Margherita Biondi; Min Jae Choi; Seungjin Lee; Koen Bertens; Mingyang Wei; Ahmad R. Kirmani; Geonhui Lee; Hao Ting Kung; Lee J. Richter; Sjoerd Hoogland; Zheng Hong Lu; F. Pelayo García De Arquer; Edward H. Sargent

doi:10.1021/acsenergylett.0c02500

Control over Ligand Exchange Reactivity in Hole Transport Layer Enables High-Efficiency Colloidal Quantum Dot Solar Cells

Margherita Biondi, Min Jae Choi, Seungjin Lee, Koen Bertens, Mingyang Wei, Ahmad R. Kirmani, Geonhui Lee, Hao Ting Kung, Lee J. Richter, Sjoerd Hoogland, Zheng Hong Lu, F. Pelayo García De Arquer, Edward H. Sargent^*

^*Corresponding author for this work

Chemistry

Research output: Contribution to journal › Article › peer-review

37 Scopus citations

Abstract

Colloidal quantum dot (CQD) solar cells are solution-processed photovoltaic devices that exhibit promise in harvesting the infrared solar spectrum. Solid-state ligand exchange is the method employed to fabricate the CQD hole transport layer (HTL) in these cells: insulating oleic acid ligands are substituted with short thiol ligands (1,2-ethanedithiol) to create conductive p-type CQD solids. Thiols' high reactivity with the CQD surface results in rapid exchange, giving rise to aggregates of dots and unpassivated sites on dots, each contributing to sub-bandgap trap states. Here we report a strategy to minimize trap states in the CQD HTL by controlling the solvent type in the exchange. By employing a less volatile solvent, we achieve a slower reaction, leading to increased order and a 2 times reduced trap density in CQD solids. These improvements enable a power conversion efficiency of 13.1 ± 0.1% in CQD solar cells compared to control devices showing 12.4 ± 0.1%.

Original language	English (US)
Pages (from-to)	468-476
Number of pages	9
Journal	ACS Energy Letters
Volume	6
Issue number	2
DOIs	https://doi.org/10.1021/acsenergylett.0c02500
State	Published - Feb 12 2021

ASJC Scopus subject areas

Chemistry (miscellaneous)
Renewable Energy, Sustainability and the Environment
Fuel Technology
Energy Engineering and Power Technology
Materials Chemistry

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1021/acsenergylett.0c02500

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Biondi, M., Choi, M. J., Lee, S., Bertens, K., Wei, M., Kirmani, A. R., Lee, G., Kung, H. T., Richter, L. J., Hoogland, S., Lu, Z. H., García De Arquer, F. P., & Sargent, E. H. (2021). Control over Ligand Exchange Reactivity in Hole Transport Layer Enables High-Efficiency Colloidal Quantum Dot Solar Cells. ACS Energy Letters, 6(2), 468-476. https://doi.org/10.1021/acsenergylett.0c02500

@article{3bc843bd148a4e9780345040e92c418e,

title = "Control over Ligand Exchange Reactivity in Hole Transport Layer Enables High-Efficiency Colloidal Quantum Dot Solar Cells",

abstract = "Colloidal quantum dot (CQD) solar cells are solution-processed photovoltaic devices that exhibit promise in harvesting the infrared solar spectrum. Solid-state ligand exchange is the method employed to fabricate the CQD hole transport layer (HTL) in these cells: insulating oleic acid ligands are substituted with short thiol ligands (1,2-ethanedithiol) to create conductive p-type CQD solids. Thiols' high reactivity with the CQD surface results in rapid exchange, giving rise to aggregates of dots and unpassivated sites on dots, each contributing to sub-bandgap trap states. Here we report a strategy to minimize trap states in the CQD HTL by controlling the solvent type in the exchange. By employing a less volatile solvent, we achieve a slower reaction, leading to increased order and a 2 times reduced trap density in CQD solids. These improvements enable a power conversion efficiency of 13.1 ± 0.1% in CQD solar cells compared to control devices showing 12.4 ± 0.1%.",

author = "Margherita Biondi and Choi, {Min Jae} and Seungjin Lee and Koen Bertens and Mingyang Wei and Kirmani, {Ahmad R.} and Geonhui Lee and Kung, {Hao Ting} and Richter, {Lee J.} and Sjoerd Hoogland and Lu, {Zheng Hong} and {Garc{\'i}a De Arquer}, {F. Pelayo} and Sargent, {Edward H.}",

note = "Funding Information: This work was supported by the Ontario Research Fund-Research Excellence program (ORF7 ministry of Research and Innovation, Ontario Research Fund-Research Excellence Round 7) and by the Natural Sciences and Engineering Research Council (NSERC) of Canada. This work was also supported by the Dongguk University Research Fund of 2020. The authors acknowledge the financial support from QD Solar. This research used resources of the National Synchrotron Light Source II, which are U.S. DOE Office of Science Facilities, at Brookhaven National Laboratory under contract no. DE-SC0012704. We thank D. Kopilovic, E. Palmiano, L. Levina, and R. Wolowiec for the technical support. Publisher Copyright: {\textcopyright} 2021 American Chemical Society.",

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Biondi, M, Choi, MJ, Lee, S, Bertens, K, Wei, M, Kirmani, AR, Lee, G, Kung, HT, Richter, LJ, Hoogland, S, Lu, ZH, García De Arquer, FP & Sargent, EH 2021, 'Control over Ligand Exchange Reactivity in Hole Transport Layer Enables High-Efficiency Colloidal Quantum Dot Solar Cells', ACS Energy Letters, vol. 6, no. 2, pp. 468-476. https://doi.org/10.1021/acsenergylett.0c02500

TY - JOUR

T1 - Control over Ligand Exchange Reactivity in Hole Transport Layer Enables High-Efficiency Colloidal Quantum Dot Solar Cells

AU - Biondi, Margherita

AU - Choi, Min Jae

AU - Lee, Seungjin

AU - Bertens, Koen

AU - Wei, Mingyang

AU - Kirmani, Ahmad R.

AU - Lee, Geonhui

AU - Kung, Hao Ting

AU - Richter, Lee J.

AU - Hoogland, Sjoerd

AU - Lu, Zheng Hong

AU - García De Arquer, F. Pelayo

AU - Sargent, Edward H.

N1 - Funding Information: This work was supported by the Ontario Research Fund-Research Excellence program (ORF7 ministry of Research and Innovation, Ontario Research Fund-Research Excellence Round 7) and by the Natural Sciences and Engineering Research Council (NSERC) of Canada. This work was also supported by the Dongguk University Research Fund of 2020. The authors acknowledge the financial support from QD Solar. This research used resources of the National Synchrotron Light Source II, which are U.S. DOE Office of Science Facilities, at Brookhaven National Laboratory under contract no. DE-SC0012704. We thank D. Kopilovic, E. Palmiano, L. Levina, and R. Wolowiec for the technical support. Publisher Copyright: © 2021 American Chemical Society.

PY - 2021/2/12

Y1 - 2021/2/12

N2 - Colloidal quantum dot (CQD) solar cells are solution-processed photovoltaic devices that exhibit promise in harvesting the infrared solar spectrum. Solid-state ligand exchange is the method employed to fabricate the CQD hole transport layer (HTL) in these cells: insulating oleic acid ligands are substituted with short thiol ligands (1,2-ethanedithiol) to create conductive p-type CQD solids. Thiols' high reactivity with the CQD surface results in rapid exchange, giving rise to aggregates of dots and unpassivated sites on dots, each contributing to sub-bandgap trap states. Here we report a strategy to minimize trap states in the CQD HTL by controlling the solvent type in the exchange. By employing a less volatile solvent, we achieve a slower reaction, leading to increased order and a 2 times reduced trap density in CQD solids. These improvements enable a power conversion efficiency of 13.1 ± 0.1% in CQD solar cells compared to control devices showing 12.4 ± 0.1%.

AB - Colloidal quantum dot (CQD) solar cells are solution-processed photovoltaic devices that exhibit promise in harvesting the infrared solar spectrum. Solid-state ligand exchange is the method employed to fabricate the CQD hole transport layer (HTL) in these cells: insulating oleic acid ligands are substituted with short thiol ligands (1,2-ethanedithiol) to create conductive p-type CQD solids. Thiols' high reactivity with the CQD surface results in rapid exchange, giving rise to aggregates of dots and unpassivated sites on dots, each contributing to sub-bandgap trap states. Here we report a strategy to minimize trap states in the CQD HTL by controlling the solvent type in the exchange. By employing a less volatile solvent, we achieve a slower reaction, leading to increased order and a 2 times reduced trap density in CQD solids. These improvements enable a power conversion efficiency of 13.1 ± 0.1% in CQD solar cells compared to control devices showing 12.4 ± 0.1%.

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U2 - 10.1021/acsenergylett.0c02500

DO - 10.1021/acsenergylett.0c02500

M3 - Article

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VL - 6

SP - 468

EP - 476

JO - ACS Energy Letters

JF - ACS Energy Letters

IS - 2

ER -

Control over Ligand Exchange Reactivity in Hole Transport Layer Enables High-Efficiency Colloidal Quantum Dot Solar Cells

Abstract

ASJC Scopus subject areas

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