Conjugated polymer-fullerene blend with strong optical limiting in the near-infrared.

Optical-quality, melt processable thick films of a conjugated polymer blend containing poly(2-methoxy-5-(2-ethyl-hexyloxy)-(phenylene vinylene)) (MEH-PPV), a C(60) derivative (PCBM) and a plasticizer (1,2-di-iso-octylphthalate) have been developed and their nonlinear absorption and optical limiting properties have been investigated. These blend materials exhibited strong optical limiting characteristics in the near infrared region (750-900 nm), with broad temporal dynamic range spanning femtosecond to nanosecond pulse widths. The dispersion of the optical limiting figure-of-merit of the MEH-PPV:PCBM:DOP blend shows a peak near the wavelength of the MEH-PPV cation, indicating an important role of one-photon and two-photon induced charge transfer in the nonlinear absorption response.