On Optical Dipole Moment and Radiative Recombination Lifetime of Excitons in WSe2

Chenhao Jin, Jonghwan Kim, Kedi Wu, Bin Chen, Edward S. Barnard, Joonki Suh, Zhiwen Shi, Steven G. Drapcho, Junqiao Wu, Peter James Schuck, Sefaattin Tongay, Feng Wang

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Optical dipole moment is the key parameter of optical transitions, as it directly determines the strength of light-matter interaction such as intrinsic radiative lifetime. However, experimental determination of these fundamental properties of excitons in monolayer WSe2 is largely limited, because the commonly used measurement, such as (time-resolved) photoluminescence, is inherently difficult to probe the intrinsic properties. For example, dark states below bright exciton can change the photoluminescence emission rate by orders of magnitude and gives an "effective" radiative lifetime distinctive from the intrinsic one. On the other hand, such "effective" radiative lifetime becomes important itself because it describes how dark states affect exciton dynamics. Unfortunately, the "effective" radiative lifetime in monolayer WSe2 is also not determined as it requires photoluminescence measurement with resonant excitation, which is technically difficult. These difficulties are overcome here to obtain both the "intrinsic" and "effective" radiative lifetime experimentally. A framework is developed to determine the dipole moment and "intrinsic" radiative lifetime of delocalized excitons in monolayer WSe2 from the absorption measurements. In addition, the "effective" radiative lifetime in WSe2 is obtained through time-resolved photoluminescence and absolute quantum-yield measurement at resonant excitation. These results provide helpful information for fundamental understanding of exciton light-matter interaction in WSe2.

Original languageEnglish (US)
JournalAdvanced Functional Materials
DOIs
StateAccepted/In press - 2016

Fingerprint

Dipole moment
radiative lifetime
radiative recombination
Excitons
dipole moments
excitons
Photoluminescence
life (durability)
Monolayers
photoluminescence
Optical transitions
Quantum yield
LDS 751
optical transition
excitation
interactions
probes

Keywords

  • Dark states
  • Delocalized excitons
  • Dipole moments
  • Radiative lifetimes
  • WSe

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Condensed Matter Physics
  • Electrochemistry

Cite this

On Optical Dipole Moment and Radiative Recombination Lifetime of Excitons in WSe2 . / Jin, Chenhao; Kim, Jonghwan; Wu, Kedi; Chen, Bin; Barnard, Edward S.; Suh, Joonki; Shi, Zhiwen; Drapcho, Steven G.; Wu, Junqiao; Schuck, Peter James; Tongay, Sefaattin; Wang, Feng.

In: Advanced Functional Materials, 2016.

Research output: Contribution to journalArticle

Jin, C, Kim, J, Wu, K, Chen, B, Barnard, ES, Suh, J, Shi, Z, Drapcho, SG, Wu, J, Schuck, PJ, Tongay, S & Wang, F 2016, 'On Optical Dipole Moment and Radiative Recombination Lifetime of Excitons in WSe2 ', Advanced Functional Materials. https://doi.org/10.1002/adfm.201601741
Jin, Chenhao ; Kim, Jonghwan ; Wu, Kedi ; Chen, Bin ; Barnard, Edward S. ; Suh, Joonki ; Shi, Zhiwen ; Drapcho, Steven G. ; Wu, Junqiao ; Schuck, Peter James ; Tongay, Sefaattin ; Wang, Feng. / On Optical Dipole Moment and Radiative Recombination Lifetime of Excitons in WSe2 In: Advanced Functional Materials. 2016.
@article{4279fb8724b541fe9d18bfea22acecd1,
title = "On Optical Dipole Moment and Radiative Recombination Lifetime of Excitons in WSe2",
abstract = "Optical dipole moment is the key parameter of optical transitions, as it directly determines the strength of light-matter interaction such as intrinsic radiative lifetime. However, experimental determination of these fundamental properties of excitons in monolayer WSe2 is largely limited, because the commonly used measurement, such as (time-resolved) photoluminescence, is inherently difficult to probe the intrinsic properties. For example, dark states below bright exciton can change the photoluminescence emission rate by orders of magnitude and gives an {"}effective{"} radiative lifetime distinctive from the intrinsic one. On the other hand, such {"}effective{"} radiative lifetime becomes important itself because it describes how dark states affect exciton dynamics. Unfortunately, the {"}effective{"} radiative lifetime in monolayer WSe2 is also not determined as it requires photoluminescence measurement with resonant excitation, which is technically difficult. These difficulties are overcome here to obtain both the {"}intrinsic{"} and {"}effective{"} radiative lifetime experimentally. A framework is developed to determine the dipole moment and {"}intrinsic{"} radiative lifetime of delocalized excitons in monolayer WSe2 from the absorption measurements. In addition, the {"}effective{"} radiative lifetime in WSe2 is obtained through time-resolved photoluminescence and absolute quantum-yield measurement at resonant excitation. These results provide helpful information for fundamental understanding of exciton light-matter interaction in WSe2.",
keywords = "Dark states, Delocalized excitons, Dipole moments, Radiative lifetimes, WSe",
author = "Chenhao Jin and Jonghwan Kim and Kedi Wu and Bin Chen and Barnard, {Edward S.} and Joonki Suh and Zhiwen Shi and Drapcho, {Steven G.} and Junqiao Wu and Schuck, {Peter James} and Sefaattin Tongay and Feng Wang",
year = "2016",
doi = "10.1002/adfm.201601741",
language = "English (US)",
journal = "Advanced Functional Materials",
issn = "1616-301X",
publisher = "Wiley-VCH Verlag",

}

TY - JOUR

T1 - On Optical Dipole Moment and Radiative Recombination Lifetime of Excitons in WSe2

AU - Jin, Chenhao

AU - Kim, Jonghwan

AU - Wu, Kedi

AU - Chen, Bin

AU - Barnard, Edward S.

AU - Suh, Joonki

AU - Shi, Zhiwen

AU - Drapcho, Steven G.

AU - Wu, Junqiao

AU - Schuck, Peter James

AU - Tongay, Sefaattin

AU - Wang, Feng

PY - 2016

Y1 - 2016

N2 - Optical dipole moment is the key parameter of optical transitions, as it directly determines the strength of light-matter interaction such as intrinsic radiative lifetime. However, experimental determination of these fundamental properties of excitons in monolayer WSe2 is largely limited, because the commonly used measurement, such as (time-resolved) photoluminescence, is inherently difficult to probe the intrinsic properties. For example, dark states below bright exciton can change the photoluminescence emission rate by orders of magnitude and gives an "effective" radiative lifetime distinctive from the intrinsic one. On the other hand, such "effective" radiative lifetime becomes important itself because it describes how dark states affect exciton dynamics. Unfortunately, the "effective" radiative lifetime in monolayer WSe2 is also not determined as it requires photoluminescence measurement with resonant excitation, which is technically difficult. These difficulties are overcome here to obtain both the "intrinsic" and "effective" radiative lifetime experimentally. A framework is developed to determine the dipole moment and "intrinsic" radiative lifetime of delocalized excitons in monolayer WSe2 from the absorption measurements. In addition, the "effective" radiative lifetime in WSe2 is obtained through time-resolved photoluminescence and absolute quantum-yield measurement at resonant excitation. These results provide helpful information for fundamental understanding of exciton light-matter interaction in WSe2.

AB - Optical dipole moment is the key parameter of optical transitions, as it directly determines the strength of light-matter interaction such as intrinsic radiative lifetime. However, experimental determination of these fundamental properties of excitons in monolayer WSe2 is largely limited, because the commonly used measurement, such as (time-resolved) photoluminescence, is inherently difficult to probe the intrinsic properties. For example, dark states below bright exciton can change the photoluminescence emission rate by orders of magnitude and gives an "effective" radiative lifetime distinctive from the intrinsic one. On the other hand, such "effective" radiative lifetime becomes important itself because it describes how dark states affect exciton dynamics. Unfortunately, the "effective" radiative lifetime in monolayer WSe2 is also not determined as it requires photoluminescence measurement with resonant excitation, which is technically difficult. These difficulties are overcome here to obtain both the "intrinsic" and "effective" radiative lifetime experimentally. A framework is developed to determine the dipole moment and "intrinsic" radiative lifetime of delocalized excitons in monolayer WSe2 from the absorption measurements. In addition, the "effective" radiative lifetime in WSe2 is obtained through time-resolved photoluminescence and absolute quantum-yield measurement at resonant excitation. These results provide helpful information for fundamental understanding of exciton light-matter interaction in WSe2.

KW - Dark states

KW - Delocalized excitons

KW - Dipole moments

KW - Radiative lifetimes

KW - WSe

UR - http://www.scopus.com/inward/record.url?scp=84989216755&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84989216755&partnerID=8YFLogxK

U2 - 10.1002/adfm.201601741

DO - 10.1002/adfm.201601741

M3 - Article

AN - SCOPUS:84989216755

JO - Advanced Functional Materials

JF - Advanced Functional Materials

SN - 1616-301X

ER -