Interchain vs. intrachain energy transfer in acceptor-capped conjugated polymers.

نویسندگان

  • D Beljonne
  • G Pourtois
  • C Silva
  • E Hennebicq
  • L M Herz
  • R H Friend
  • G D Scholes
  • S Setayesh
  • K Mullen
  • J L Bredas
چکیده

The energy-transfer processes taking place in conjugated polymers are investigated by means of ultrafast spectroscopy and correlated quantum-chemical calculations applied to polyindenofluorenes end-capped with a perylene derivative. Comparison between the time-integrated luminescence and transient absorption spectra measured in solution and in films allows disentangling of the contributions arising from intrachain and from interchain energy-migration phenomena. Intrachain processes dominate in solution where photoexcitation of the polyindenofluorene units induces a rather slow energy transfer to the perylene end moieties. In films, close contacts between chains favors interchain transport of the excited singlet species (from the conjugated bridge of one chain to the perylene unit of a neighboring one); this process is characterized by a 1-order-of-magnitude increase in transfer rate with respect to solution. This description is supported fully by the results of quantum-chemical calculations that go beyond the usual point-dipole model approximation and account for geometric relaxation phenomena in the excited state before energy migration. The calculations indicate a two-step mechanism for intrachain energy transfer with hopping along the conjugated chains as the rate-limiting step; the higher efficiency of the interchain transfer process is mainly due to larger electronic coupling matrix elements between closely lying chains.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Control of energy transfer in oriented conjugated polymer-mesoporous silica composites

Nanoscale architecture was used to control energy transfer in semiconducting polymers embedded in the channels of oriented, hexagonal nanoporous silica. Polarized femtosecond spectroscopies show that excitations migrate unidirectionally from aggregated, randomly oriented polymer segments outside the pores to isolated, aligned polymer chains within the pores. Energy migration along the conjugate...

متن کامل

Charge- and energy-transfer processes at polymer/polymer interfaces: A joint experimental and theoretical study

When an exciton approaches the interface between two conjugated polymers, either energy or charge transfer can take place. We present a detailed experimental investigation of these processes in various binary polymer systems. The results are interpreted in the context of quantum-chemical calculations that provide estimates of the relative energies of intrachain versus interchain excited states ...

متن کامل

Exciton migration in rigid-rod conjugated polymers: an improved Förster model.

The dynamics of interchain and intrachain excitation energy transfer taking place in a polyindenofluorene endcapped with perylene derivatives is explored by means of ultrafast spectroscopy combined with correlated quantum-chemical calculations. The experimental data indicate faster exciton migration in films with respect to solution as a result of the emergence of efficient channels involving h...

متن کامل

Interchain coupling effects on dynamics of photoexcitations in conjugated polymers.

Within an extended Su-Schrieffer-Heeger model including interchain interactions and the extended Hubbard model, the dynamical relaxation of photoexcitations in two coupled conjugated polymer chains is investigated by using a nonadiabatic evolution method. Initially, one of the two chains is photoexcited and the other chain is in the dimerized ground state. Due to the interchain interactions, th...

متن کامل

Interchain and intrachain exciton transport in conjugated polymers: ultrafast studies of energy migration in aligned MEH-PPV/mesoporous silica composites

In this paper, we show how composite samples consisting of chains of the semiconducting polymer MEH-PPV embedded into the channels of oriented, hexagonal nanoporous silica glass allow control over energy transfer and exciton migration in the polymer. The composite samples are characterized by two polymer environments: randomly oriented and ®lm-like segments with short conjugationlength outside ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Proceedings of the National Academy of Sciences of the United States of America

دوره 99 17  شماره 

صفحات  -

تاریخ انتشار 2002