A $dC/dV$ Measurement for Quantum-Dot Light-Emitting Diodes
Jingrui Ma1,2, Haodong Tang1,2, Xiangwei Qu1,2, Guohong Xiang1,2, Siqi Jia1,2, Pai Liu1,2, Kai Wang1,2,3, and Xiao Wei Sun1,2,3*
1Key Laboratory of Energy Conversion and Storage Technologies (SUSTech) of Ministry of Education, Guangdong-Hong Kong-Macao Joint Laboratory for Photonic-Thermal-Electrical Energy Materials and Devices, SUSTech-Huawei Joint Lab for Photonics Industry, and Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China 2Institute of Nanoscience and Applications, Southern University of Science and Technology, Shenzhen 518055, China 3Shenzhen Planck Innovation Technologies Co. Ltd., Shenzhen 518173, China
Abstract：We present $dC/dV$ analysis based on the capacitance-voltage ($C$–$V$) measurement of quantum-dot light-emitting diodes (QLEDs), and find that some key device operating parameters (electrical and optical turn-on voltage, peak capacitance, maximum efficiency) can be directly related to the turning points and maximum/minimum of the $dC/dV$ (versus voltage) curve. By the $dC/dV$ study, the behaviors such as low turn-on voltage, simultaneous electrical and optical turn-on process, and carrier accumulation during the device aging can be well explained. Moreover, we perform the $C$–$V$ and $dC/dV$ measurement of aged devices, and confirm that our $dC/dV$ analysis is correct for them. Thus, our $dC/dV$ analysis method can be applied universally for QLED devices. It provides an in-depth understanding of carrier dynamics in QLEDs through simple $C$–$V$ measurement.
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2022, Vol. 39 
