Nanostructure-dependent vertical charge transport in MEH-PPV films

Yi-Fang Huang, Jesuraj Inigo, Chia-Chen Chang, Kang-Chuang Li, Chiao-Tan Liang, Chan-Wei Chang, Tsong-Shin Lim, Su-Hua Chen, Jonathon David White, U-Ser Jeng, An-Chung Su, Ying-Sheng Huang, Kang-Yung Peng, Show-An Chen, Woei-Wu Pai, Chen-Hong Lin, Lexey R. Tameev, Sergey V. Novikov, Anatoly V. Vannikov, Wun-Shain Fann

Research output: Contribution to journalArticle

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Abstract

The correlation between morphology and charge-carrier mobility in the vertical direction in thin films of poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) is investigated by a combination of X-ray reflectivity (XRR), field-emission scanning electron microscopy (FESEM), atomic force rnicroscopy (AFM), fluorescence optical microscopy (FOM), photoluminescence spectroscopy (PL), photoluminescence excitation spectroscopy (PLE), as well as time-of-flight (TOF) and transient electroluminescence (TrEL) techniques. The mobility is about two orders of magnitude greater for drop-cast films than for their spin-cast counterparts. Drop-casting in the presence of a vertical static electric field (E-casting) results in films with an additional increase in mobility of about one order of magnitude. While PL and PLE spectra vary with the method of film preparation, there is no correlation between emission spectra and charge-carrier mobility. Our XRR measurements on spin-cast films indicate layering along the film depth while no such structure is found in drop-cast or E-cast films, whereas FESEM examination indicates that nanodomains within drop-cast films are eliminated in the E-cast case. These observations indicate that carrier transport is influenced by structure on two different length scales. The low mobility observed in spin-cast films is a direct result of a global layered structure with characteristic thickness of ca. 4 nm: in the absence of this layered structure, drop-cast films with inherent nanoscale heterogeneities (ca. 20 nm in size) exhibit much better hole mobility. Elimination of nanodomains via electric-field alignment results in further improved charge mobility.

LanguageEnglish
Pages2902-2910
Number of pages9
JournalAdvanced Functional Materials
Volume17
Issue number15
Early online date28 Aug 2007
DOIs
Publication statusPublished - 15 Oct 2007

Fingerprint

Charge transfer
casts
Nanostructures
Photoluminescence spectroscopy
photoluminescence
Carrier mobility
Charge carriers
Field emission
carrier mobility
Photoluminescence
spectroscopy
Casting
charge carriers
field emission
Electric fields
Spectroscopy
Film preparation
X rays
Scanning electron microscopy
Hole mobility

Keywords

  • Poly(p-phenylene vinylene)s
  • interchain interactions
  • electric-field
  • electroluminescence
  • hole transport
  • carrier mobility
  • device performance
  • light-emitting-diodes
  • morphology
  • conjugated polymers

Cite this

Huang, Y-F., Inigo, J., Chang, C-C., Li, K-C., Liang, C-T., Chang, C-W., ... Fann, W-S. (2007). Nanostructure-dependent vertical charge transport in MEH-PPV films. Advanced Functional Materials, 17(15), 2902-2910. https://doi.org/10.1002/adfm.200600825
Huang, Yi-Fang ; Inigo, Jesuraj ; Chang, Chia-Chen ; Li, Kang-Chuang ; Liang, Chiao-Tan ; Chang, Chan-Wei ; Lim, Tsong-Shin ; Chen, Su-Hua ; White, Jonathon David ; Jeng, U-Ser ; Su, An-Chung ; Huang, Ying-Sheng ; Peng, Kang-Yung ; Chen, Show-An ; Pai, Woei-Wu ; Lin, Chen-Hong ; Tameev, Lexey R. ; Novikov, Sergey V. ; Vannikov, Anatoly V. ; Fann, Wun-Shain. / Nanostructure-dependent vertical charge transport in MEH-PPV films. In: Advanced Functional Materials. 2007 ; Vol. 17, No. 15. pp. 2902-2910.
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abstract = "The correlation between morphology and charge-carrier mobility in the vertical direction in thin films of poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) is investigated by a combination of X-ray reflectivity (XRR), field-emission scanning electron microscopy (FESEM), atomic force rnicroscopy (AFM), fluorescence optical microscopy (FOM), photoluminescence spectroscopy (PL), photoluminescence excitation spectroscopy (PLE), as well as time-of-flight (TOF) and transient electroluminescence (TrEL) techniques. The mobility is about two orders of magnitude greater for drop-cast films than for their spin-cast counterparts. Drop-casting in the presence of a vertical static electric field (E-casting) results in films with an additional increase in mobility of about one order of magnitude. While PL and PLE spectra vary with the method of film preparation, there is no correlation between emission spectra and charge-carrier mobility. Our XRR measurements on spin-cast films indicate layering along the film depth while no such structure is found in drop-cast or E-cast films, whereas FESEM examination indicates that nanodomains within drop-cast films are eliminated in the E-cast case. These observations indicate that carrier transport is influenced by structure on two different length scales. The low mobility observed in spin-cast films is a direct result of a global layered structure with characteristic thickness of ca. 4 nm: in the absence of this layered structure, drop-cast films with inherent nanoscale heterogeneities (ca. 20 nm in size) exhibit much better hole mobility. Elimination of nanodomains via electric-field alignment results in further improved charge mobility.",
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author = "Yi-Fang Huang and Jesuraj Inigo and Chia-Chen Chang and Kang-Chuang Li and Chiao-Tan Liang and Chan-Wei Chang and Tsong-Shin Lim and Su-Hua Chen and White, {Jonathon David} and U-Ser Jeng and An-Chung Su and Ying-Sheng Huang and Kang-Yung Peng and Show-An Chen and Woei-Wu Pai and Chen-Hong Lin and Tameev, {Lexey R.} and Novikov, {Sergey V.} and Vannikov, {Anatoly V.} and Wun-Shain Fann",
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Huang, Y-F, Inigo, J, Chang, C-C, Li, K-C, Liang, C-T, Chang, C-W, Lim, T-S, Chen, S-H, White, JD, Jeng, U-S, Su, A-C, Huang, Y-S, Peng, K-Y, Chen, S-A, Pai, W-W, Lin, C-H, Tameev, LR, Novikov, SV, Vannikov, AV & Fann, W-S 2007, 'Nanostructure-dependent vertical charge transport in MEH-PPV films' Advanced Functional Materials, vol. 17, no. 15, pp. 2902-2910. https://doi.org/10.1002/adfm.200600825

Nanostructure-dependent vertical charge transport in MEH-PPV films. / Huang, Yi-Fang; Inigo, Jesuraj; Chang, Chia-Chen; Li, Kang-Chuang; Liang, Chiao-Tan; Chang, Chan-Wei; Lim, Tsong-Shin; Chen, Su-Hua; White, Jonathon David; Jeng, U-Ser; Su, An-Chung; Huang, Ying-Sheng; Peng, Kang-Yung; Chen, Show-An; Pai, Woei-Wu; Lin, Chen-Hong; Tameev, Lexey R.; Novikov, Sergey V.; Vannikov, Anatoly V.; Fann, Wun-Shain.

In: Advanced Functional Materials, Vol. 17, No. 15, 15.10.2007, p. 2902-2910.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Nanostructure-dependent vertical charge transport in MEH-PPV films

AU - Huang, Yi-Fang

AU - Inigo, Jesuraj

AU - Chang, Chia-Chen

AU - Li, Kang-Chuang

AU - Liang, Chiao-Tan

AU - Chang, Chan-Wei

AU - Lim, Tsong-Shin

AU - Chen, Su-Hua

AU - White, Jonathon David

AU - Jeng, U-Ser

AU - Su, An-Chung

AU - Huang, Ying-Sheng

AU - Peng, Kang-Yung

AU - Chen, Show-An

AU - Pai, Woei-Wu

AU - Lin, Chen-Hong

AU - Tameev, Lexey R.

AU - Novikov, Sergey V.

AU - Vannikov, Anatoly V.

AU - Fann, Wun-Shain

PY - 2007/10/15

Y1 - 2007/10/15

N2 - The correlation between morphology and charge-carrier mobility in the vertical direction in thin films of poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) is investigated by a combination of X-ray reflectivity (XRR), field-emission scanning electron microscopy (FESEM), atomic force rnicroscopy (AFM), fluorescence optical microscopy (FOM), photoluminescence spectroscopy (PL), photoluminescence excitation spectroscopy (PLE), as well as time-of-flight (TOF) and transient electroluminescence (TrEL) techniques. The mobility is about two orders of magnitude greater for drop-cast films than for their spin-cast counterparts. Drop-casting in the presence of a vertical static electric field (E-casting) results in films with an additional increase in mobility of about one order of magnitude. While PL and PLE spectra vary with the method of film preparation, there is no correlation between emission spectra and charge-carrier mobility. Our XRR measurements on spin-cast films indicate layering along the film depth while no such structure is found in drop-cast or E-cast films, whereas FESEM examination indicates that nanodomains within drop-cast films are eliminated in the E-cast case. These observations indicate that carrier transport is influenced by structure on two different length scales. The low mobility observed in spin-cast films is a direct result of a global layered structure with characteristic thickness of ca. 4 nm: in the absence of this layered structure, drop-cast films with inherent nanoscale heterogeneities (ca. 20 nm in size) exhibit much better hole mobility. Elimination of nanodomains via electric-field alignment results in further improved charge mobility.

AB - The correlation between morphology and charge-carrier mobility in the vertical direction in thin films of poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) is investigated by a combination of X-ray reflectivity (XRR), field-emission scanning electron microscopy (FESEM), atomic force rnicroscopy (AFM), fluorescence optical microscopy (FOM), photoluminescence spectroscopy (PL), photoluminescence excitation spectroscopy (PLE), as well as time-of-flight (TOF) and transient electroluminescence (TrEL) techniques. The mobility is about two orders of magnitude greater for drop-cast films than for their spin-cast counterparts. Drop-casting in the presence of a vertical static electric field (E-casting) results in films with an additional increase in mobility of about one order of magnitude. While PL and PLE spectra vary with the method of film preparation, there is no correlation between emission spectra and charge-carrier mobility. Our XRR measurements on spin-cast films indicate layering along the film depth while no such structure is found in drop-cast or E-cast films, whereas FESEM examination indicates that nanodomains within drop-cast films are eliminated in the E-cast case. These observations indicate that carrier transport is influenced by structure on two different length scales. The low mobility observed in spin-cast films is a direct result of a global layered structure with characteristic thickness of ca. 4 nm: in the absence of this layered structure, drop-cast films with inherent nanoscale heterogeneities (ca. 20 nm in size) exhibit much better hole mobility. Elimination of nanodomains via electric-field alignment results in further improved charge mobility.

KW - Poly(p-phenylene vinylene)s

KW - interchain interactions

KW - electric-field

KW - electroluminescence

KW - hole transport

KW - carrier mobility

KW - device performance

KW - light-emitting-diodes

KW - morphology

KW - conjugated polymers

U2 - 10.1002/adfm.200600825

DO - 10.1002/adfm.200600825

M3 - Article

VL - 17

SP - 2902

EP - 2910

JO - Advanced Functional Materials

T2 - Advanced Functional Materials

JF - Advanced Functional Materials

SN - 1616-301X

IS - 15

ER -

Huang Y-F, Inigo J, Chang C-C, Li K-C, Liang C-T, Chang C-W et al. Nanostructure-dependent vertical charge transport in MEH-PPV films. Advanced Functional Materials. 2007 Oct 15;17(15):2902-2910. https://doi.org/10.1002/adfm.200600825