Optical response of conjugated polymers excited at high intensity

• Published in: Synthetic metals Vol. 102; no. 1; pp. 1008 - 1009
• Main Authors: Denton, G.J., Tessler, N., Stevens, M.A., Friend, R.H.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 01-06-1999; Amsterdam Elsevier Science; New York, NY
• Subjects: Applied sciences; Electrical, magnetic and optical properties; Exact sciences and technology; Organic polymers; Photoconductivity; Physicochemistry of polymers; Poly(phenylene vinylene) and derivatives; Properties and characterization; Time-resolved fast spectroscopy; Time-resolved fast spectroscopy; Photoconductivity; Poly(phenylene vinylene) and derivatives
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/S0379-6779(98)01253-3

The realisation of optically pumped lasing devices using poly(
p-phenylenevinylene) has intensified interest in the optical response of conjugated polymers on ultra-short time-scales and at high optical injection density. We describe an investigation of these properties using time-resolved and time-integrated techniques. We demonstrate the importance of exciton-exciton annihilation at high injection densities and present evidence that this process produces photo-induced absorption (PA) through the generation of charges. We present a model which accounts for PA from both photoexcited singlet excitons and the charge pairs generated by annihilation. This model describes the time-evolution of the PA well and indicates that, in the presence of exciton-exciton annihilation, dissimilar stimulated emission and PA dynamics are consistent with a high quantum yield of excitons as deduced from PL lifetime and efficiency studies.