Chlorinated indium tin oxide as a charge injecting electrode for admittance spectroscopy

Admittance spectroscopy (AS) is a simple technique to measure the carrier mobility of organic semiconductors, but requires an Ohmic contact for charge injection. Chlorinated indium tin oxide (Cl-ITO) is shown to be a good charge injecting electrode for AS due to its high work function of >6.1 eV. The mobility of N,N′-diphenyl-N,N′-bis-(1-naphthyl)-1-1′-biphenyl-4,4′-diamine (α-NPD) measured with Cl-ITO was found to be in excellent agreement with the value measured by time of flight. Cl-ITO is therefore an ideal electrode for AS since it possesses a high work function, but does not introduce any series impedance into the device structure.

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► Cl-ITO has a high work function and is a good electrode for AS.
► The mobility measured using AS with Cl-ITO is in agreement with TOF measurements.
► Cl-ITO is an ideal electrode for AS as it does not introduce any series impedance.