Short-diode like diffusion capacitance of organic light emission devices

Mei Na Tsai, T. C. Chang*, Po-Tsun Liu, Chung Wen Ko, Che Jen Chen, Kang Mien Lo

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

30 Scopus citations


A prototypical organic light-emitting diode (OLED), anode/organic layers/cathode, is investigated via bias-dependent capacitance measurement of two-layer (HTL/ETL) and four-layer (HIL/HTL/EML/ETL) structure at low frequency. As applied voltage was larger than the built-in voltage, the capacitance is augmented by diffusion capacitance with increasing the forward bias voltage. In contrast, the capacitance dropped quickly. It is possibly due to the voltage drop in the bulk and conductivity modulation occurred by high carrier concentration for much higher forward biases, eventually showing negative for two-layer OLEDs. We infer that the phenomena were resulted from the extremely thin OLED structure, just like short p-n semiconductor diodes. This diffusion capacitance exhibiting like short-diode behavior also can be measured in C-V curves of single-layer structure OLED.

Original languageEnglish
Pages (from-to)244-248
Number of pages5
JournalThin Solid Films
Issue number1-2
StatePublished - 1 Mar 2006
EventProceedings of the Third Asian Conference on Chemical Vapor Deposition (Third Asian-CVD), Third Asian CVD -
Duration: 12 Nov 200414 Nov 2004


  • Diffusion capacitance
  • Non-combination carriers
  • OLED


Dive into the research topics of 'Short-diode like diffusion capacitance of organic light emission devices'. Together they form a unique fingerprint.

Cite this