Optical Capacitance/Conductance-Voltage Characteristics of Stored Charges in Organic Light-Emitting Diodes

Molecules

Ahmed Al-Ghamdi¹  Chengwen Zhang¹  S. Wageh¹  Suling Zhao¹  Peng Wang²  Zheng Xu²  Zilun Qin² 

[1] Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia;Key Laboratory of Luminescence and Optical Information, Ministry of Education, Beijing Jiaotong University, Beijing 100044, China;

关键词: organic light-emitting diodes;    interfacial charges;    stored charges;    optical capacitance/conductance-voltage;   

DOI  :  10.3390/molecules25122818

来源: DOAJ

【 摘 要 】

In this paper, capacitance/conductance-voltage characteristics (C/G-V) under illumination was achieved to investigate the dynamic mechanism of stored charges in OLEDs with a structure of ITO/ PEDOT:PSS/PMMA/Alq₃/Al. For all devices, at least two peaks presented in the optical capacitance-voltage curve. Compared to curves of devices under dark, the first peak increased remarkably with a deviation to V_bi, which can be explained in the form of stored charges combined with the optical conductance characteristics. It was also found that a great decrease in capacitance is followed by the collapse of the first peak with PMMA thickness increased. It can account for the presence of interfacial charges, which is proved further by the conductance curves. To the device with 10nm PMMA, a third peak took place in optical capacitance and it was due to the storage of electrons by PMMA. Also, the first capacitance peak enhanced approximate linearly as the illumination power increased, which can verify the contribution of the stored charges. Additionally, it shows the potential for the stored charges in optical detections.

【 授权许可】

Unknown