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

Zhang, Chengwen; Xu, Zheng; Wang, Peng; Qin, Zilun; Wageh, S.; Al-Ghamdi, Ahmed; Zhao, Suling

doi:10.3390/molecules25122818

Open AccessArticle

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

by

Chengwen Zhang

^1,2

,

Zheng Xu

²,

Peng Wang

²,

Zilun Qin

²,

S. Wageh

^1,3,*

,

Ahmed Al-Ghamdi

¹ and

Suling Zhao

^1,2,*

¹

Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia

²

Key Laboratory of Luminescence and Optical Information, Ministry of Education, Beijing Jiaotong University, Beijing 100044, China

³

Physics and Engineering Mathematics Department, Faculty of Electronic Engineering, Menoufia University, Menouf 32952, Egypt

^*

Authors to whom correspondence should be addressed.

Molecules 2020, 25(12), 2818; https://doi.org/10.3390/molecules25122818

Submission received: 26 May 2020 / Revised: 13 June 2020 / Accepted: 16 June 2020 / Published: 18 June 2020

(This article belongs to the Special Issue Organic Light Emitting Diodes II)

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Abstract

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 10 nm 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.

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

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MDPI and ACS Style

Zhang, C.; Xu, Z.; Wang, P.; Qin, Z.; Wageh, S.; Al-Ghamdi, A.; Zhao, S. Optical Capacitance/Conductance-Voltage Characteristics of Stored Charges in Organic Light-Emitting Diodes. Molecules 2020, 25, 2818. https://doi.org/10.3390/molecules25122818

AMA Style

Zhang C, Xu Z, Wang P, Qin Z, Wageh S, Al-Ghamdi A, Zhao S. Optical Capacitance/Conductance-Voltage Characteristics of Stored Charges in Organic Light-Emitting Diodes. Molecules. 2020; 25(12):2818. https://doi.org/10.3390/molecules25122818

Chicago/Turabian Style

Zhang, Chengwen, Zheng Xu, Peng Wang, Zilun Qin, S. Wageh, Ahmed Al-Ghamdi, and Suling Zhao. 2020. "Optical Capacitance/Conductance-Voltage Characteristics of Stored Charges in Organic Light-Emitting Diodes" Molecules 25, no. 12: 2818. https://doi.org/10.3390/molecules25122818

APA Style

Zhang, C., Xu, Z., Wang, P., Qin, Z., Wageh, S., Al-Ghamdi, A., & Zhao, S. (2020). Optical Capacitance/Conductance-Voltage Characteristics of Stored Charges in Organic Light-Emitting Diodes. Molecules, 25(12), 2818. https://doi.org/10.3390/molecules25122818

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

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