Ultrafast photo-conductivity in BAMH-PPV polymer thin-films

The carrier life time in poly(2,5-bis[N-methyl-N-hexylamino]phenylene vinylene (BAMH-PPV) is measured by photo-conductive sampling. A systematic study of the influence of both external bias electric field and illumination intensity on the photo-conductance of the polymer is carried out. The photo-conductance remained roughly constant with the applied electric field up to 6 × 105 V/cm. Electric pulsewidths of 2 ps were measured. The transient carrier mobility is calculated. For 93 nm thick film the lower limit is estimated to be 0.24 (cm2/V s) when assuming unity quantum efficiency. This transient mobility value could be 480 (cm2/V s) when taking quantum efficiency to be 0.05% according to Hendry et al. [E. Hendry, M. Koeberg, J. M. Schins, L.D.A. Siebbeles and M. Bonn, Phys. Rev. B. 70 (2004) 033202].