Influence of Energetic Disorder on Exciton Lifetime and Photoluminescence Efficiency in Conjugated Polymers.

Using time-resolved photoluminescence (TRPL) spectroscopy the exciton lifetime in a range of conjugated polymers is investigated. For poly(p-phenylenevinylene) (PPV)-based derivatives and a polyspirobifluorene copolymer (PSBF) we find that the exciton lifetime is correlated with the energetic disorder. Better ordered polymers exhibit a single exponential PL decay with exciton lifetimes of a few hundred picoseconds, whereas polymers with a larger degree of disorder show multiexponential PL decays with exciton lifetimes in the nanosecond regime. These observations are consistent with diffusion-limited exciton quenching at nonradiative recombination centers. The measured PL decay time reflects the time that excitons need to diffuse toward these quenching sites. Conjugated polymers with large energetic disorder and thus longer exciton lifetime also exhibit a higher photoluminescence quantum yield due to the slower exciton diffusion toward nonradiative quenching sites.

[1]  P. Blom,et al.  Exciton diffusion in organic semiconductors , 2015 .

[2]  P. Blom,et al.  Trap‐Limited Exciton Diffusion in Organic Semiconductors , 2014, Advanced materials.

[3]  S. Haque,et al.  Determining the Exciton Diffusion Length in a Polyfluorene from Ultrafast Fluorescence Measurements of Polymer/Fullerene Blend Films , 2013 .

[4]  S. Gambino,et al.  Photophysical and charge-transporting properties of the copolymer SuperYellow , 2013 .

[5]  H. Bässler,et al.  To Hop or Not to Hop? Understanding the Temperature Dependence of Spectral Diffusion in Organic Semiconductors. , 2013, The journal of physical chemistry letters.

[6]  P. Blom,et al.  Effect of thermal annealing on exciton diffusion in a diketopyrrolopyrrole derivative. , 2012, Physical chemistry chemical physics : PCCP.

[7]  P. Blom,et al.  Unification of trap-limited electron transport in semiconducting polymers. , 2012, Nature materials.

[8]  Shane R. Yost,et al.  Triplet vs Singlet Energy Transfer in Organic Semiconductors: The Tortoise and the Hare , 2012 .

[9]  H. Bässler,et al.  How do Triplets and Charges Move in Disordered Organic Semiconductors? A Monte Carlo Study Comprising the Equilibrium and Nonequilibrium Regime , 2012 .

[10]  Mauro Morana,et al.  Exciton diffusion length in narrow bandgap polymers , 2012 .

[11]  H. Nicolai,et al.  Quantitative analysis of the guest-concentration dependence of the mobility in a disordered fluorene-arylamine host-guest system in the guest-to-guest regime , 2011 .

[12]  G. Scholes,et al.  Electronic Energy Transfer and Quantum-Coherence in π-Conjugated Polymers† , 2011 .

[13]  H. Bässler,et al.  What determines inhomogeneous broadening of electronic transitions in conjugated polymers? , 2010, The journal of physical chemistry. B.

[14]  David Beljonne,et al.  Modelling exciton diffusion in disordered conjugated polymers , 2010, Photonics Europe.

[15]  A. Monkman,et al.  High photoluminescence quantum yield due to intramolecular energy transfer in the Super Yellow conjugated copolymer , 2010 .

[16]  H. Bässler,et al.  Spectral diffusion in poly(para-phenylene)-type polymers with different energetic disorder , 2010 .

[17]  David Beljonne,et al.  Exciton diffusion in energetically disordered organic materials , 2009 .

[18]  S. Clark,et al.  The complex excited-state behavior of a polyspirobifluorene derivative: the role of spiroconjugation and mixed charge transfer character on excited-state stabilization and radiative lifetime. , 2008, The journal of physical chemistry. B.

[19]  P. Blom,et al.  Temperature dependence of exciton diffusion in conjugated polymers. , 2008, The journal of physical chemistry. B.

[20]  I. Samuel,et al.  Exciton Diffusion Measurements in Poly(3‐hexylthiophene) , 2008 .

[21]  David Beljonne,et al.  Trap Limited Exciton Transport in Conjugated Polymers , 2008 .

[22]  A. Monkman,et al.  Spiroconjugation-Enhanced Intramolecular Charge-Transfer State Formation in a Polyspirobifluorene Homopolymer , 2007 .

[23]  R. Friend,et al.  Role of intermolecular coupling in the photophysics of disordered organic semiconductors: aggregate emission in regioregular polythiophene. , 2007, Physical review letters.

[24]  P. Blom,et al.  Anisotropy of exciton migration in poly(p-phenylene vinylene) , 2006 .

[25]  P. Blom,et al.  Dynamics of exciton diffusion in poly( p -phenylene vinylene)/fullerene heterostructures , 2005 .

[26]  Jurjen Wildeman,et al.  Simultaneous enhancement of charge transport and exciton diffusion in poly(p-phenylene vinylene) derivatives , 2005 .

[27]  G. Pourtois,et al.  Exciton migration in rigid-rod conjugated polymers: an improved Förster model. , 2005, Journal of the American Chemical Society.

[28]  T. Pullerits,et al.  Spectroscopic units in conjugated polymers: a quantum chemically founded concept? , 2004, The journal of physical chemistry. B.

[29]  M. Andersson,et al.  Photophysics of thiophene based polymers in solution: The role of nonradiative decay processes , 2003 .

[30]  R. Friend,et al.  Interchain vs. intrachain energy transfer in acceptor-capped conjugated polymers , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[31]  C. Bardeen,et al.  Use of Picosecond Fluorescence Dynamics as an Indicator of Exciton Motion in Conjugated Polymers: Dependence on Chemical Structure and Temperature , 2001 .

[32]  C. Collison,et al.  Conformational Effects on the Photophysics of Conjugated Polymers: A Two Species Model for MEH−PPV Spectroscopy and Dynamics , 2001 .

[33]  Doan,et al.  Control of energy transfer in oriented conjugated polymer-mesoporous silica composites , 2000, Science.

[34]  P. Blom,et al.  Comparative study of hole transport in poly(p-phenylene vinylene) derivatives , 2000 .

[35]  E. List,et al.  Kinetics of singlet and triplet excitons in a wide-band-gap copolymer , 2000 .

[36]  Harrison,et al.  Singlet Intrachain Exciton Generation and Decay in Poly (p-phenylenevinylene). , 1996, Physical review letters.

[37]  Kurz,et al.  Dynamics of singlet excitations in conjugated polymers: Poly(phenylenevinylene) and poly(phenylphenylenevinylene). , 1994, Physical review. B, Condensed matter.

[38]  Miller,et al.  Defect quenching of conjugated polymer luminescence. , 1994, Physical review letters.

[39]  Kurz,et al.  Femtosecond energy relaxation in pi -conjugated polymers. , 1993, Physical review letters.

[40]  A. J. Heeger,et al.  Photoinduced Electron Transfer from a Conducting Polymer to Buckminsterfullerene , 1992, Science.

[41]  F. E. Karasz,et al.  Polaron-pair generation in poly(phenylene vinylenes). , 1992, Physical review. B, Condensed matter.

[42]  Gailberger,et al.  dc and transient photoconductivity of poly(2-phenyl-1,4-phenylenevinylene). , 1991, Physical review. B, Condensed matter.

[43]  Bassler,et al.  Diffusion and relaxation of energy in disordered organic and inorganic materials. , 1986, Physical review. B, Condensed matter.

[44]  B. Movaghar,et al.  Theory of non-equilibrium diffusive transport in disordered materials , 1984 .

[45]  S. Tolbert,et al.  Interchain and intrachain exciton transport in conjugated polymers: ultrafast studies of energy migration in aligned MEH-PPV/mesoporous silica composites , 2001 .

[46]  Hsieh,et al.  Assignment of the picosecond photoinduced absorption in phenylene vinylene polymers. , 1994, Physical review. B, Condensed matter.

[47]  H. Bässler.  Charge Transport in Disordered Organic Photoconductors a Monte Carlo Simulation Study , 1993 .