A metrology perspective on the dark injection transient current method for charge mobility determination in organic semiconductors

Abstract

Charge mobility is a key parameter for understanding the performance of organic semiconductor devices and materials. A range of techniques is available that can measure charge mobility with varying accuracy and precision. In this paper we analyze the dark injection transient current (DITC) method from a metrology perspective. We carried out a systematic study of the sensitivity of single carrier analogues of organic light-emitting diodes (OLEDs) to small changes in electrical input and environmental conditions. We observed that the experimental results depend strongly on the previous history of the device under test, with both long term and short term effects in evidence. Our findings demonstrate the need for caution in interpreting the results of single experiments to determine the charge mobility of OLEDs and the difficulty of associating uncertainty statements with the results of charge mobility measurements.