Mechanisms of Ultrafast Charge Separation in a PTB7/Monolayer MoS2 van der Waals Heterojunction

Chengmei Zhong, Vinod K. Sangwan, Chen Wang, Hadallia Bergeron, Mark C Hersam, Emily A Weiss

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Mixed-dimensional van der Waals heterojunctions comprising polymer and two-dimensional (2D) semiconductors have many characteristics of an ideal charge separation interface for optoelectronic and photonic applications. However, the photoelectron dynamics at polymer-2D semiconductor heterojunction interfaces are currently not sufficiently understood to guide the optimization of devices for these applications. This Letter reports a systematic exploration of the time-dependent photophysical processes that occur upon photoexcitation of a type-II heterojunction between the polymer PTB7 and monolayer MoS2. In particular, photoinduced electron transfer from PTB7 to electronically hot states of MoS2 occurs in less than 250 fs. This process is followed by a 1-5 ps exciton diffusion-limited electron transfer from PTB7 to MoS2 and a sub-3 ps photoinduced hole transfer from MoS2 to PTB7. The equilibrium between excitons and polaron pairs in PTB7 determines the charge separation yield, whereas the 3-4 ns lifetime of photogenerated carriers is probably limited by MoS2 defects.

Original languageEnglish
Pages (from-to)2484-2491
Number of pages8
JournalJournal of Physical Chemistry Letters
Volume9
Issue number10
DOIs
Publication statusPublished - May 17 2018

Fingerprint

polarization (charge separation)
Heterojunctions
heterojunctions
Monolayers
Polymers
Excitons
electron transfer
polymers
excitons
Semiconductor materials
Gene Conversion
Electrons
Photoexcitation
Photoelectrons
photoexcitation
Optoelectronic devices
Photonics
photoelectrons
photonics
life (durability)

ASJC Scopus subject areas

  • Materials Science(all)

Cite this

Mechanisms of Ultrafast Charge Separation in a PTB7/Monolayer MoS2 van der Waals Heterojunction. / Zhong, Chengmei; Sangwan, Vinod K.; Wang, Chen; Bergeron, Hadallia; Hersam, Mark C; Weiss, Emily A.

In: Journal of Physical Chemistry Letters, Vol. 9, No. 10, 17.05.2018, p. 2484-2491.

Research output: Contribution to journalArticle

Zhong, Chengmei ; Sangwan, Vinod K. ; Wang, Chen ; Bergeron, Hadallia ; Hersam, Mark C ; Weiss, Emily A. / Mechanisms of Ultrafast Charge Separation in a PTB7/Monolayer MoS2 van der Waals Heterojunction. In: Journal of Physical Chemistry Letters. 2018 ; Vol. 9, No. 10. pp. 2484-2491.
@article{224b32d3fd104cf9bd3b969a32e694ec,
title = "Mechanisms of Ultrafast Charge Separation in a PTB7/Monolayer MoS2 van der Waals Heterojunction",
abstract = "Mixed-dimensional van der Waals heterojunctions comprising polymer and two-dimensional (2D) semiconductors have many characteristics of an ideal charge separation interface for optoelectronic and photonic applications. However, the photoelectron dynamics at polymer-2D semiconductor heterojunction interfaces are currently not sufficiently understood to guide the optimization of devices for these applications. This Letter reports a systematic exploration of the time-dependent photophysical processes that occur upon photoexcitation of a type-II heterojunction between the polymer PTB7 and monolayer MoS2. In particular, photoinduced electron transfer from PTB7 to electronically hot states of MoS2 occurs in less than 250 fs. This process is followed by a 1-5 ps exciton diffusion-limited electron transfer from PTB7 to MoS2 and a sub-3 ps photoinduced hole transfer from MoS2 to PTB7. The equilibrium between excitons and polaron pairs in PTB7 determines the charge separation yield, whereas the 3-4 ns lifetime of photogenerated carriers is probably limited by MoS2 defects.",
author = "Chengmei Zhong and Sangwan, {Vinod K.} and Chen Wang and Hadallia Bergeron and Hersam, {Mark C} and Weiss, {Emily A}",
year = "2018",
month = "5",
day = "17",
doi = "10.1021/acs.jpclett.8b00628",
language = "English",
volume = "9",
pages = "2484--2491",
journal = "Journal of Physical Chemistry Letters",
issn = "1948-7185",
publisher = "American Chemical Society",
number = "10",

}

TY - JOUR

T1 - Mechanisms of Ultrafast Charge Separation in a PTB7/Monolayer MoS2 van der Waals Heterojunction

AU - Zhong, Chengmei

AU - Sangwan, Vinod K.

AU - Wang, Chen

AU - Bergeron, Hadallia

AU - Hersam, Mark C

AU - Weiss, Emily A

PY - 2018/5/17

Y1 - 2018/5/17

N2 - Mixed-dimensional van der Waals heterojunctions comprising polymer and two-dimensional (2D) semiconductors have many characteristics of an ideal charge separation interface for optoelectronic and photonic applications. However, the photoelectron dynamics at polymer-2D semiconductor heterojunction interfaces are currently not sufficiently understood to guide the optimization of devices for these applications. This Letter reports a systematic exploration of the time-dependent photophysical processes that occur upon photoexcitation of a type-II heterojunction between the polymer PTB7 and monolayer MoS2. In particular, photoinduced electron transfer from PTB7 to electronically hot states of MoS2 occurs in less than 250 fs. This process is followed by a 1-5 ps exciton diffusion-limited electron transfer from PTB7 to MoS2 and a sub-3 ps photoinduced hole transfer from MoS2 to PTB7. The equilibrium between excitons and polaron pairs in PTB7 determines the charge separation yield, whereas the 3-4 ns lifetime of photogenerated carriers is probably limited by MoS2 defects.

AB - Mixed-dimensional van der Waals heterojunctions comprising polymer and two-dimensional (2D) semiconductors have many characteristics of an ideal charge separation interface for optoelectronic and photonic applications. However, the photoelectron dynamics at polymer-2D semiconductor heterojunction interfaces are currently not sufficiently understood to guide the optimization of devices for these applications. This Letter reports a systematic exploration of the time-dependent photophysical processes that occur upon photoexcitation of a type-II heterojunction between the polymer PTB7 and monolayer MoS2. In particular, photoinduced electron transfer from PTB7 to electronically hot states of MoS2 occurs in less than 250 fs. This process is followed by a 1-5 ps exciton diffusion-limited electron transfer from PTB7 to MoS2 and a sub-3 ps photoinduced hole transfer from MoS2 to PTB7. The equilibrium between excitons and polaron pairs in PTB7 determines the charge separation yield, whereas the 3-4 ns lifetime of photogenerated carriers is probably limited by MoS2 defects.

UR - http://www.scopus.com/inward/record.url?scp=85046397829&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85046397829&partnerID=8YFLogxK

U2 - 10.1021/acs.jpclett.8b00628

DO - 10.1021/acs.jpclett.8b00628

M3 - Article

VL - 9

SP - 2484

EP - 2491

JO - Journal of Physical Chemistry Letters

JF - Journal of Physical Chemistry Letters

SN - 1948-7185

IS - 10

ER -