Electric Field Dependent Carrier Mobility of Quantum Dots Film

Considering the importance of carrier mobility in developing quantum dots based devices, accurately measuring the carrier mobility of nanocrystal films has been of great significance. In this work, we illustrate the electric field dependent carrier mobility of films by developing numerical simulation assisted space charge limited current (NS-SCLC) measurements. We determined current density-voltage (<i>J</i>-<i>V</i>) curves of single carrier devices (hole-only or electron-only). By considering voltage drops of the transport layer, anode electrode, and interface, the voltage drop on quantum dots films in electron- or hole-only devices can be derived to describe the <i>J</i>-<i>V</i> characteristics of quantum dots. Combining the hopping transport mechanism and numerical simulation method, the <i>J</i>-<i>V</i> characteristics of quantum dots films can be fitted to obtain the carrier mobility (μ) under different electric fields. Then, we measured a series of quantum dots and the key materials in quantum dot light-emitting diodes. Our work not only provides a method to accurately measure electric field dependent carrier mobility but also highlights the importance of the electric field dependence of carrier mobility in developing quantum dots based devices.