Enhanced spin-orbit coupling driven by state mixing in organic molecules for OLED applications

Tzu Ting Huang, Elise Yu-Tzu Li

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

We investigate the energy gap variation as well as spin-orbit coupling (SOC) integrals between various low-lying singlet and triplet excited states for a series of fluorescein derivatives. We find that when the electron-donating property of the substituent group on the benzene moiety of fluorescein is gradually increased, the charge transfer states are lowered in energy and a mixing with nearby ππ* or nπ* states occurs, which causes a twisting in the p orbital on the carbonyl group and a non-zero SOC integral between the originally non-coupled 1ππ* and 3ππ* states. We also find an enhancement of about 3–4 times in the SOC integrals upon sulfur substitution for the oxygen in the carbonyl groups, and that with substantial energy lowering in ππ* and especially in nπ* states, the SOC between the S1 state with energetically close triplet states is also increased significantly, signifying the possibility of enhanced phosphorescence or thermally-delayed fluorescence emission.

Original languageEnglish
Pages (from-to)311-317
Number of pages7
JournalOrganic Electronics
Volume39
DOIs
Publication statusPublished - 2016 Dec 1

Fingerprint

Organic light emitting diodes (OLED)
Orbits
orbits
Molecules
Fluorescein
molecules
Phosphorescence
twisting
phosphorescence
Benzene
Sulfur
Excited states
atomic energy levels
Charge transfer
Energy gap
Substitution reactions
sulfur
Fluorescence
benzene
charge transfer

Keywords

  • Organic light-emitting diodes
  • Spin-orbit coupling
  • Thermally activated delayed fluorescence

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering

Cite this

Enhanced spin-orbit coupling driven by state mixing in organic molecules for OLED applications. / Huang, Tzu Ting; Li, Elise Yu-Tzu.

In: Organic Electronics, Vol. 39, 01.12.2016, p. 311-317.

Research output: Contribution to journalArticle

@article{0328328eeb1544fba3001c406d4f4a9d,
title = "Enhanced spin-orbit coupling driven by state mixing in organic molecules for OLED applications",
abstract = "We investigate the energy gap variation as well as spin-orbit coupling (SOC) integrals between various low-lying singlet and triplet excited states for a series of fluorescein derivatives. We find that when the electron-donating property of the substituent group on the benzene moiety of fluorescein is gradually increased, the charge transfer states are lowered in energy and a mixing with nearby ππ* or nπ* states occurs, which causes a twisting in the p orbital on the carbonyl group and a non-zero SOC integral between the originally non-coupled 1ππ* and 3ππ* states. We also find an enhancement of about 3–4 times in the SOC integrals upon sulfur substitution for the oxygen in the carbonyl groups, and that with substantial energy lowering in ππ* and especially in nπ* states, the SOC between the S1 state with energetically close triplet states is also increased significantly, signifying the possibility of enhanced phosphorescence or thermally-delayed fluorescence emission.",
keywords = "Organic light-emitting diodes, Spin-orbit coupling, Thermally activated delayed fluorescence",
author = "Huang, {Tzu Ting} and Li, {Elise Yu-Tzu}",
year = "2016",
month = "12",
day = "1",
doi = "10.1016/j.orgel.2016.10.026",
language = "English",
volume = "39",
pages = "311--317",
journal = "Organic Electronics: physics, materials, applications",
issn = "1566-1199",
publisher = "Elsevier",

}

TY - JOUR

T1 - Enhanced spin-orbit coupling driven by state mixing in organic molecules for OLED applications

AU - Huang, Tzu Ting

AU - Li, Elise Yu-Tzu

PY - 2016/12/1

Y1 - 2016/12/1

N2 - We investigate the energy gap variation as well as spin-orbit coupling (SOC) integrals between various low-lying singlet and triplet excited states for a series of fluorescein derivatives. We find that when the electron-donating property of the substituent group on the benzene moiety of fluorescein is gradually increased, the charge transfer states are lowered in energy and a mixing with nearby ππ* or nπ* states occurs, which causes a twisting in the p orbital on the carbonyl group and a non-zero SOC integral between the originally non-coupled 1ππ* and 3ππ* states. We also find an enhancement of about 3–4 times in the SOC integrals upon sulfur substitution for the oxygen in the carbonyl groups, and that with substantial energy lowering in ππ* and especially in nπ* states, the SOC between the S1 state with energetically close triplet states is also increased significantly, signifying the possibility of enhanced phosphorescence or thermally-delayed fluorescence emission.

AB - We investigate the energy gap variation as well as spin-orbit coupling (SOC) integrals between various low-lying singlet and triplet excited states for a series of fluorescein derivatives. We find that when the electron-donating property of the substituent group on the benzene moiety of fluorescein is gradually increased, the charge transfer states are lowered in energy and a mixing with nearby ππ* or nπ* states occurs, which causes a twisting in the p orbital on the carbonyl group and a non-zero SOC integral between the originally non-coupled 1ππ* and 3ππ* states. We also find an enhancement of about 3–4 times in the SOC integrals upon sulfur substitution for the oxygen in the carbonyl groups, and that with substantial energy lowering in ππ* and especially in nπ* states, the SOC between the S1 state with energetically close triplet states is also increased significantly, signifying the possibility of enhanced phosphorescence or thermally-delayed fluorescence emission.

KW - Organic light-emitting diodes

KW - Spin-orbit coupling

KW - Thermally activated delayed fluorescence

UR - http://www.scopus.com/inward/record.url?scp=84992609000&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84992609000&partnerID=8YFLogxK

U2 - 10.1016/j.orgel.2016.10.026

DO - 10.1016/j.orgel.2016.10.026

M3 - Article

AN - SCOPUS:84992609000

VL - 39

SP - 311

EP - 317

JO - Organic Electronics: physics, materials, applications

JF - Organic Electronics: physics, materials, applications

SN - 1566-1199

ER -