Transport properties of triarylamine based dendrimers studied by space charge limited current transients

We have studied hole transport in triarylamine based dendrimer using space-charge-limited current transient technique. A mobility of 8 × 10−6 cm2/(V s) and a characteristic detrapping time of about 100 ms have been obtained. We found that quasi-ohmic contact is formed with gold. The obtained mobility differs from the apparent one given by the analysis of stationary current–voltage characteristics because of a limited contact efficiency. The comparison between transients obtained from fresh and aged samples reveals no change in mobility with aging. The deterioration of electrical properties is exclusively caused by trap formation and accumulation of ionic conducting impurities. Finally, repeated transient measurements have been applied to analyze the dynamics of charge trapping process.

► This study concerns organic semi-conductors in general. ► We have performed transient space charge limited current measurements. ► We could estimate contact efficiency. ► We carried out measurement of electrical mobility. ► We showed how to evaluate trapping effects.