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Title: Measurements of photo-induced changes in conjugated polymers

Abstract

We have used the highly sensitive technique of Photothermal Deflection Spectroscopy (PDS) to measure changes in the infrared absorption spectra of MEHPPV, P3HT and Polydiacetylene-4BCMU induced by pumping these polymers with light above the {pi}--{pi}* transition energy. In contrast to previous chopped light transmission measurements of these effects, the PDS technique can directly measure the buildup or decay of the absorption coefficient, {alpha}, on the time scale of second to days. In the case of MEHPPV we observe that the time scale of seconds to days. In the case of MEHPPV we observe that above-gap light causes the appearance of a broad infrared peak in {alpha}, which continues to grow-in hours after the pump light is first applied. For this polymer the general shape of the absorption spectra in the unpumped state mimics the photo-induced changes, suggesting that remnant photo-induced states determine the maximum transparency observed under normal experimental conditions. For P3HT and to a lesser extent, MEHPPV, we also observe irreversible photo-induced absorption components which we tentatively identify with photo-induced oxidation of the polymer matrix. 10 refs., 8 figs.

Authors:
;  [1]; ;  [2];  [3]
  1. (Sandia National Labs., Albuquerque, NM (USA))
  2. (California Univ., Santa Barbara, CA (USA))
  3. (Bell Communications Research, Inc., Red Bank, NJ (USA))
Publication Date:
Research Org.:
Sandia National Labs., Albuquerque, NM (USA)
Sponsoring Org.:
USDOE; USDOE, Washington, DC (USA)
OSTI Identifier:
5553662
Report Number(s):
SAND-91-1000C; CONF-910406-14
ON: DE91013262
DOE Contract Number:  
AC04-76DP00789
Resource Type:
Conference
Resource Relation:
Conference: Spring meeting of the Materials Research Society (MRS), Anaheim, CA (USA), 29 Apr - 3 May 1991
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; POLYMERS; INFRARED SPECTRA; ABSORPTION; DECAY; EXCITATION; LIGHT TRANSMISSION; OPACITY; POLARONS; WAVEGUIDES; WAVELENGTHS; ENERGY-LEVEL TRANSITIONS; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; QUASI PARTICLES; SPECTRA; 360603* - Materials- Properties

Citation Formats

Seager, C.H., Sinclair, M.B., Mc Branch, D., Heeger, A.J., and Baker, G.L.. Measurements of photo-induced changes in conjugated polymers. United States: N. p., 1991. Web.
Seager, C.H., Sinclair, M.B., Mc Branch, D., Heeger, A.J., & Baker, G.L.. Measurements of photo-induced changes in conjugated polymers. United States.
Seager, C.H., Sinclair, M.B., Mc Branch, D., Heeger, A.J., and Baker, G.L.. Tue . "Measurements of photo-induced changes in conjugated polymers". United States. doi:. https://www.osti.gov/servlets/purl/5553662.
@article{osti_5553662,
title = {Measurements of photo-induced changes in conjugated polymers},
author = {Seager, C.H. and Sinclair, M.B. and Mc Branch, D. and Heeger, A.J. and Baker, G.L.},
abstractNote = {We have used the highly sensitive technique of Photothermal Deflection Spectroscopy (PDS) to measure changes in the infrared absorption spectra of MEHPPV, P3HT and Polydiacetylene-4BCMU induced by pumping these polymers with light above the {pi}--{pi}* transition energy. In contrast to previous chopped light transmission measurements of these effects, the PDS technique can directly measure the buildup or decay of the absorption coefficient, {alpha}, on the time scale of second to days. In the case of MEHPPV we observe that the time scale of seconds to days. In the case of MEHPPV we observe that above-gap light causes the appearance of a broad infrared peak in {alpha}, which continues to grow-in hours after the pump light is first applied. For this polymer the general shape of the absorption spectra in the unpumped state mimics the photo-induced changes, suggesting that remnant photo-induced states determine the maximum transparency observed under normal experimental conditions. For P3HT and to a lesser extent, MEHPPV, we also observe irreversible photo-induced absorption components which we tentatively identify with photo-induced oxidation of the polymer matrix. 10 refs., 8 figs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 01 00:00:00 EST 1991},
month = {Tue Jan 01 00:00:00 EST 1991}
}

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