Role of the Dielectric Nature of the Transparent Contact in Charge Injection and Collection in Organic Optoelectronic Devices

Dor Gotleyb, Rafi Shikler

Research output: Contribution to journalArticlepeer-review


We report for the first time on the implications of the dielectric nature of transparent electrodes, not only their low conductivity, but also on charge injection and collection. Transparent electrodes are common in organic-based optoelectronic devices because of the small diffusion length of charged carriers that requires complete coverage by the electrode. The commonly reported drawback of transparent electrodes is their low conductivity, which leads to unwanted power dissipation. However, there is no reference to the influence of the dielectric nature on the contact properties. The effect of the dielectric nature is introduced by modifying the expression for the image potential and the resulting barrier lowering at the transparent contact. The model is verified by fabricating and measuring simple unipolar devices, which show excellent agreement with the proposed modification. Without a modification, in order to have a good fitting, there should have been unrealistic values for some parameters, for example, a dielectric constant of 23 for the organic layer. The modified expression is then inspected in numerical simulations to study its nonlinear influence on the device. We find that using our model with typical device parameters, the predicted current density of the device is around half of the value calculated for a metallic electrode. Similar results are obtained by reducing the value of the mobility while keeping the injection condition for a metallic electrode. This explains why this property has been overlooked and is an indication of the extreme care needed when fitting experimental results.

Original languageAmerican English
Article number014029
JournalPhysical Review Applied
Issue number1
StatePublished - 16 Jul 2019

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


Dive into the research topics of 'Role of the Dielectric Nature of the Transparent Contact in Charge Injection and Collection in Organic Optoelectronic Devices'. Together they form a unique fingerprint.

Cite this