Nonlinear Exciton Relaxation in Ladder-Type Poly (Para-Phenylene)

Abstract

Nonlinear exciton relaxation processes, exciton-exciton annihilation, and amplified spontaneous emission were investigated in thin films of ladder-type poly-(para-phenylene) under excitation by femtosecond light pulses. Both processes become apparent at similar excitation intensities, however their properties are very different. They cause different exciton relaxation kinetics and their intensity dependences are different.

Keywords:

• annihilation
• ASE
• conjugated polymer
• femtosecond

Acknowledgments

The investigation was partly supported by the Lithuanian State Foundation for Science and Studies. We thank Prof. Scherf for placing MeLPPP at our disposal.