Exciton and biexciton signatures in femtosecond transient absorption of pi-conjugated oligomers

Victor I. Klimov; Duncan W. McBranch; Nikolay N. Barashkov; John P. Ferraris

doi:10.1117/12.295539

1 December 1997 Exciton and biexciton signatures in femtosecond transient absorption of π-conjugated oligomers

Victor I. Klimov, Duncan W. McBranch, Nikolay N. Barashkov, John P. Ferraris

Author Affiliations +

Proceedings Volume 3145, Optical Probes of Conjugated Polymers; (1997) https://doi.org/10.1117/12.295539
Event: Optical Science, Engineering and Instrumentation '97, 1997, San Diego, CA, United States

Abstract

We report femtosecond transient-absorption studies of a five-ring oligomer of polyphenylenevinylene prepared in two different forms: as solid-state films and dilute solutions. Both types of samples exhibit a photoinduced absorption (PA) band with dynamics which closely match those of the stimulated emission (SE), demonstrating unambiguously that these features originate from the same species, namely from intrachain singlet excitons. Photochemical degradation of the solid-state samples is demonstrated to dramatically shorten the SE dynamics above a moderate incident pump fluence, whereupon the dynamics of the SE and the long- wavelength PA no longer coincide. In contrast to solutions, solid-state films exhibit an additional short-wavelength PA band with pump-independent dynamics, indicating the efficient formation of non-emissive inter-chain excitons. Correlations in the subpicosecond dynamics of the two PA features, as well as the pump intensity-dependence provide strong evidence that the formation of inter-chain excitons is mediated by intrachain two-exciton states. At high pump levels, we see a clear indication of interaction between excited states also in dilute solutions. This is manifested as a superlinear pump-dependence and shortening of the decay dynamics of the SE. We attribute this behavior to the formation of biexcitons resulting from coherent interaction between two excitons on a single chain.

Citation Download Citation

Victor I. Klimov, Duncan W. McBranch, Nikolay N. Barashkov, and John P. Ferraris "Exciton and biexciton signatures in femtosecond transient absorption of π-conjugated oligomers", Proc. SPIE 3145, Optical Probes of Conjugated Polymers, (1 December 1997); https://doi.org/10.1117/12.295539

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

;

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE