High-color-rendering-index white polymer light-emitting electrochemical cells based on ionic host-guest systems

Utilization of blend films of blue-fluorescent cationic polyfluorenes and red-phosphorescent cationic iridium complexes

Yoshinori Nishikitani, Kotaro Suga, Soichi Uchida, Suzushi Nishimura, Kenichi Oyaizu, Hiroyuki Nishide

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The authors present high-color-rendering-index (CRI) white polymer light-emitting electrochemical cells (PLECs) based on ionic host-guest systems. PLECs were fabricated with blend films composed of a blue fluorescent cationic π-conjugated polymer, poly(9,9-bis[6′-(N,N,N,-trimethylammonium)hexyl]fluorine-co-alt-1,4-phenylene)bromide (PFN+Br), used as a host, and a red phosphorescent cationic iridium complex, [Ir(ppy)2(biq)]+(PF6) (where (ppy) = 2-phenylpyridinate and biq = 2,2′-biquinoline), used as a guest. By optimizing the composition of PFN+Br and [Ir(ppy)2(biq)]+(PF6) in the active layers, white light emission with Commission Internationale de l'Eclairage (CIE) coordinates of (x = 0.28, y = 0.31) and a very high CRI of 95.8 was achieved through mixing of blue and red light at an applied voltage of 4.0 V. The white light emissions were obtained at a low [Ir(ppy)2(biq)]+(PF6) concentration (PFN+Br:[Ir(ppy)2(biq)]+(PF6) = 1:0.01 (mass ratio)), showing that [Ir(ppy)2(biq)]+(PF6) acts as a suitable energy acceptor. The emission mechanism of the ionic host-guest PLECs can be explained by Förster resonance energy transfer (FRET) and Dexter energy transfer (DET) from the excited PFN+Br to [Ir(ppy)2(biq)]+(PF6). Utilization of ionic host-guest PLECs is a very promising method for realizing white light-emitting devices with very high CRI.

Original languageEnglish
Pages (from-to)168-172
Number of pages5
JournalOrganic Electronics: physics, materials, applications
Volume51
DOIs
Publication statusPublished - 2017 Dec 1

Fingerprint

Iridium
Electrochemical cells
electrochemical cells
iridium
Polymers
Color
color
polymers
Light emission
Energy transfer
light emission
energy transfer
Fluorine
Conjugated polymers
Bromides
mass ratios
fluorine
bromides
Electric potential
electric potential

Keywords

  • Energy transfer
  • High-color-rendering-index
  • Ionic host-guest systems
  • White polymer light-emitting electrochemical cells

ASJC Scopus subject areas

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

Cite this

@article{d0833e66f9b84935a676852276216a66,
title = "High-color-rendering-index white polymer light-emitting electrochemical cells based on ionic host-guest systems: Utilization of blend films of blue-fluorescent cationic polyfluorenes and red-phosphorescent cationic iridium complexes",
abstract = "The authors present high-color-rendering-index (CRI) white polymer light-emitting electrochemical cells (PLECs) based on ionic host-guest systems. PLECs were fabricated with blend films composed of a blue fluorescent cationic π-conjugated polymer, poly(9,9-bis[6′-(N,N,N,-trimethylammonium)hexyl]fluorine-co-alt-1,4-phenylene)bromide (PFN+Br−), used as a host, and a red phosphorescent cationic iridium complex, [Ir(ppy)2(biq)]+(PF6)− (where (ppy)− = 2-phenylpyridinate and biq = 2,2′-biquinoline), used as a guest. By optimizing the composition of PFN+Br− and [Ir(ppy)2(biq)]+(PF6)− in the active layers, white light emission with Commission Internationale de l'Eclairage (CIE) coordinates of (x = 0.28, y = 0.31) and a very high CRI of 95.8 was achieved through mixing of blue and red light at an applied voltage of 4.0 V. The white light emissions were obtained at a low [Ir(ppy)2(biq)]+(PF6)− concentration (PFN+Br−:[Ir(ppy)2(biq)]+(PF6)− = 1:0.01 (mass ratio)), showing that [Ir(ppy)2(biq)]+(PF6)− acts as a suitable energy acceptor. The emission mechanism of the ionic host-guest PLECs can be explained by F{\"o}rster resonance energy transfer (FRET) and Dexter energy transfer (DET) from the excited PFN+Br− to [Ir(ppy)2(biq)]+(PF6)−. Utilization of ionic host-guest PLECs is a very promising method for realizing white light-emitting devices with very high CRI.",
keywords = "Energy transfer, High-color-rendering-index, Ionic host-guest systems, White polymer light-emitting electrochemical cells",
author = "Yoshinori Nishikitani and Kotaro Suga and Soichi Uchida and Suzushi Nishimura and Kenichi Oyaizu and Hiroyuki Nishide",
year = "2017",
month = "12",
day = "1",
doi = "10.1016/j.orgel.2017.09.003",
language = "English",
volume = "51",
pages = "168--172",
journal = "Organic Electronics: physics, materials, applications",
issn = "1566-1199",
publisher = "Elsevier",

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TY - JOUR

T1 - High-color-rendering-index white polymer light-emitting electrochemical cells based on ionic host-guest systems

T2 - Utilization of blend films of blue-fluorescent cationic polyfluorenes and red-phosphorescent cationic iridium complexes

AU - Nishikitani, Yoshinori

AU - Suga, Kotaro

AU - Uchida, Soichi

AU - Nishimura, Suzushi

AU - Oyaizu, Kenichi

AU - Nishide, Hiroyuki

PY - 2017/12/1

Y1 - 2017/12/1

N2 - The authors present high-color-rendering-index (CRI) white polymer light-emitting electrochemical cells (PLECs) based on ionic host-guest systems. PLECs were fabricated with blend films composed of a blue fluorescent cationic π-conjugated polymer, poly(9,9-bis[6′-(N,N,N,-trimethylammonium)hexyl]fluorine-co-alt-1,4-phenylene)bromide (PFN+Br−), used as a host, and a red phosphorescent cationic iridium complex, [Ir(ppy)2(biq)]+(PF6)− (where (ppy)− = 2-phenylpyridinate and biq = 2,2′-biquinoline), used as a guest. By optimizing the composition of PFN+Br− and [Ir(ppy)2(biq)]+(PF6)− in the active layers, white light emission with Commission Internationale de l'Eclairage (CIE) coordinates of (x = 0.28, y = 0.31) and a very high CRI of 95.8 was achieved through mixing of blue and red light at an applied voltage of 4.0 V. The white light emissions were obtained at a low [Ir(ppy)2(biq)]+(PF6)− concentration (PFN+Br−:[Ir(ppy)2(biq)]+(PF6)− = 1:0.01 (mass ratio)), showing that [Ir(ppy)2(biq)]+(PF6)− acts as a suitable energy acceptor. The emission mechanism of the ionic host-guest PLECs can be explained by Förster resonance energy transfer (FRET) and Dexter energy transfer (DET) from the excited PFN+Br− to [Ir(ppy)2(biq)]+(PF6)−. Utilization of ionic host-guest PLECs is a very promising method for realizing white light-emitting devices with very high CRI.

AB - The authors present high-color-rendering-index (CRI) white polymer light-emitting electrochemical cells (PLECs) based on ionic host-guest systems. PLECs were fabricated with blend films composed of a blue fluorescent cationic π-conjugated polymer, poly(9,9-bis[6′-(N,N,N,-trimethylammonium)hexyl]fluorine-co-alt-1,4-phenylene)bromide (PFN+Br−), used as a host, and a red phosphorescent cationic iridium complex, [Ir(ppy)2(biq)]+(PF6)− (where (ppy)− = 2-phenylpyridinate and biq = 2,2′-biquinoline), used as a guest. By optimizing the composition of PFN+Br− and [Ir(ppy)2(biq)]+(PF6)− in the active layers, white light emission with Commission Internationale de l'Eclairage (CIE) coordinates of (x = 0.28, y = 0.31) and a very high CRI of 95.8 was achieved through mixing of blue and red light at an applied voltage of 4.0 V. The white light emissions were obtained at a low [Ir(ppy)2(biq)]+(PF6)− concentration (PFN+Br−:[Ir(ppy)2(biq)]+(PF6)− = 1:0.01 (mass ratio)), showing that [Ir(ppy)2(biq)]+(PF6)− acts as a suitable energy acceptor. The emission mechanism of the ionic host-guest PLECs can be explained by Förster resonance energy transfer (FRET) and Dexter energy transfer (DET) from the excited PFN+Br− to [Ir(ppy)2(biq)]+(PF6)−. Utilization of ionic host-guest PLECs is a very promising method for realizing white light-emitting devices with very high CRI.

KW - Energy transfer

KW - High-color-rendering-index

KW - Ionic host-guest systems

KW - White polymer light-emitting electrochemical cells

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