Study on carrier mobility measurement using electroluminescence in frequency domain and electrochemical impedance spectroscopy

In this paper, the two methods, electroluminescence in frequency domain and electrochemical impedance spectroscopy, have been applied to investigate the carrier mobility in single layer polymer light-emitting diode employing the polymer MEH-PPV (Poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]) as the light-emitting layer. The carrier mobility μ is 1.64 × 10−6 cm2/V s under the electric field 8.3 × 105 V/cm measured by the method of electroluminescence in frequency domain. The electrochemical impedance spectroscopy results indicate that the carrier mobility μ is 1.08 × 10−6 cm2/V s under the electric field 7.5 × 105 V/cm. A significant advantage of the two methods is that both of them can be applied to measure the carrier mobility in the thin film.