Affiliation:
1. Institute of Nanoscience and Applications, and Department of Electrical and Electronic Engineering, Southern University of Science and Technology 1 , Shenzhen 518055, China
2. Key Laboratory of Energy Conversion and Storage Technologies (Southern University of Science and Technology), Ministry of Education, and Shenzhen Key Laboratory for Advanced Quantum Dot Displays and Lighting, Southern University of Science and Technology 2 , Shenzhen 518055, China
Abstract
In this work, we report the capacitance recovery behavior in the blue quantum dot light-emitting diode (QLED) by capacitance–voltage (C–V) characterizations. A comprehensive study of the C–V, dC/dV–V, and current density–voltage characteristics of pristine and shelf-aged devices suggests that capacitance recovery is associated with space charge-induced charge accumulation. At lower temperatures, the capacitance recovery in the shelf-aged device is efficiently suppressed due to the difficulty in building up the space charge, which supports our argument. Moreover, the capacitance recovery behavior of QLED only happens at low frequencies (a few hundred hertz), which is related to the time constant for charge accumulation at the selected voltage. Our work shows the effect of space charge on device capacitance and enriches the comprehension of carrier processes in QLED under AC measurement.
Funder
National Key Research and Development Program of China
National Natural Science Foundation of China
Guangdong University Key Laboratory for Advanced Quantum Dot Displays and Lighting
Shenzhen Key Laboratory for Advanced Quantum Dot Displays and Lighting
Shenzhen Science and Technology Program
Development and Reform Commission of Shenzhen Municipality
High Level of Special Fund of SUSTech