Charge Transport in Spiro-OMeTAD Investigated through Space-Charge-Limited Current Measurements

Abstract

Measuring space-charge-limited current (SCLC) is a prevalent method for estimating the charge-carrier mobility in an organic semiconductor. Extracting meaningful results can be complicated, though, since here charge transport is usually limited by traps and injection issues, leading to activation energies that must be accounted for. Typical fitting equations cannot handle this, but this study uses a drift-diffusion model to show that the mobility in a sample system is independent of temperature, field, and charge-carrier density. Alongside numerical results, an analytical model for trap-limited current in a single-carrier device is presented, for high accuracy in SCLC analysis.