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Title: Interaction of singlet excitons with polarons in wide band-gap organic semiconductors: A quantitative study

Abstract

The steady-state photoinduced absorption (PA), photoluminescence (PL), PL-detected magnetic resonance (PLDMR), and PA-detected magnetic resonance (PADMR) of poly- and oligo-(para-phenylenes) films is described. In particular, the excitation density (laser power) N{sub 0} dependence of the PA, PL, and PLDMR signals is analyzed by means of a rate equation model, which describes the dynamics of singlet excitons (SE's) and polarons in all three experiments quantitatively with the same set of parameters. The model is based on the observations that mobile SE's are quenched by trapped and free polarons and that the spin-1/2 magnetic resonance conditions reduce the total polaron population. Since the sublinear N{sub 0} dependences of the positive (PL-enhancing) spin-1/2 PLDMR and the polaron PA band are essentially the same, we conclude that PLDMR is due to a reduced quenching of SE's by polarons. The agreement between the model, the current results, and results from other spectroscopic techniques provides strong evidence for this quenching mechanism. This also suggests that it is a very significant process in luminescent {pi}-conjugated materials and organic light-emitting devices. Consequently, the quenching mechanism needs to be taken into account, especially at high excitation densities, which is of great importance for the development of electrically pumped polymermore » laser diode structures.« less

Authors:
; ; ; ; ; ;
Publication Date:
Sponsoring Org.:
(US)
OSTI Identifier:
40277703
DOE Contract Number:  
W-7405-Eng-82
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review B; Journal Volume: 64; Journal Issue: 15; Other Information: DOI: 10.1103/PhysRevB.64.155204; Othernumber: PRBMDO000064000015155204000001; 034139PRB; PBD: 15 Oct 2001
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ABSORPTION; EXCITATION; EXCITONS; LASERS; MAGNETIC RESONANCE; ORGANIC SEMICONDUCTORS; PHOTOLUMINESCENCE; POLARONS; POLYMERS; QUENCHING

Citation Formats

List, E. J. W., Kim, C.-H., Naik, A. K., Scherf, U., Leising, G., Graupner, W., and Shinar, J. Interaction of singlet excitons with polarons in wide band-gap organic semiconductors: A quantitative study. United States: N. p., 2001. Web. doi:10.1103/PhysRevB.64.155204.
List, E. J. W., Kim, C.-H., Naik, A. K., Scherf, U., Leising, G., Graupner, W., & Shinar, J. Interaction of singlet excitons with polarons in wide band-gap organic semiconductors: A quantitative study. United States. doi:10.1103/PhysRevB.64.155204.
List, E. J. W., Kim, C.-H., Naik, A. K., Scherf, U., Leising, G., Graupner, W., and Shinar, J. Mon . "Interaction of singlet excitons with polarons in wide band-gap organic semiconductors: A quantitative study". United States. doi:10.1103/PhysRevB.64.155204.
@article{osti_40277703,
title = {Interaction of singlet excitons with polarons in wide band-gap organic semiconductors: A quantitative study},
author = {List, E. J. W. and Kim, C.-H. and Naik, A. K. and Scherf, U. and Leising, G. and Graupner, W. and Shinar, J.},
abstractNote = {The steady-state photoinduced absorption (PA), photoluminescence (PL), PL-detected magnetic resonance (PLDMR), and PA-detected magnetic resonance (PADMR) of poly- and oligo-(para-phenylenes) films is described. In particular, the excitation density (laser power) N{sub 0} dependence of the PA, PL, and PLDMR signals is analyzed by means of a rate equation model, which describes the dynamics of singlet excitons (SE's) and polarons in all three experiments quantitatively with the same set of parameters. The model is based on the observations that mobile SE's are quenched by trapped and free polarons and that the spin-1/2 magnetic resonance conditions reduce the total polaron population. Since the sublinear N{sub 0} dependences of the positive (PL-enhancing) spin-1/2 PLDMR and the polaron PA band are essentially the same, we conclude that PLDMR is due to a reduced quenching of SE's by polarons. The agreement between the model, the current results, and results from other spectroscopic techniques provides strong evidence for this quenching mechanism. This also suggests that it is a very significant process in luminescent {pi}-conjugated materials and organic light-emitting devices. Consequently, the quenching mechanism needs to be taken into account, especially at high excitation densities, which is of great importance for the development of electrically pumped polymer laser diode structures.},
doi = {10.1103/PhysRevB.64.155204},
journal = {Physical Review B},
number = 15,
volume = 64,
place = {United States},
year = {Mon Oct 15 00:00:00 EDT 2001},
month = {Mon Oct 15 00:00:00 EDT 2001}
}