Online Seminar Announcement: Wednesday 7 October 2020

Due to the cancellation of many scientific conferences, the AUCAOS committee is pleased to announce an online seminar series. We intend to run seminars on the first Wednesday of every month until normal conferences can resume.

Date: Wednesday 7 October

1pm in QLD
2pm in NSW, ACT, Vic and Tas
11am in WA
12:30pm in NT
1:30pm in SA
4pm in New Zealand

Click this link to join the meeting:

Seminar schedule
Each talk is 20 minutes duration followed by approximately 5 minutes for questions and discussion.

Time (QLD time, adjust as needed): Presentation:
1:00 – 1:25pm Understanding the interplay between charge transport, luminescence efficiency and morphology in OLEDs using a combined computational & experimental approach

Mile Gao
The University of Queensland

Phosphorescent emissive materials in organic light-emitting diodes (OLEDs) manufactured using evaporation are usually blended with host materials at a concentration of 3–15 wt% to avoid concentration quenching of the luminescence. In this work, experimental measurements of hole mobility and photoluminescence are related to the atomic level morphology of films created using atomistic nonequilibrium molecular dynamics simulations mimicking the evaporation process with similar guest concentrations as that used in operational test devices. It was found that the photophysical and charge transport properties of the film have significantly different guest–guest distance dependence.

1:25 – 1:50pm The effect of gate conductance on hygroscopic insulator organic field effect transistors

Joshua Arthur
Queensland University of Technology

Organic thin film transistors (OTFTs), employing a variety of device architectures, materials, and transduction mechanisms, have shown great promise as effective chemical and biological sensors. One such class of OTFT is the hygroscopic insulator field effect transistor (HIFET). HIFETs utilise a hygroscopic polymer dielectric that behaves as a solid-state electrolyte, facilitating low voltage (<1 V) operation, in a simple, solution processable, solid-state form factor. Sensitivity to various analytes can be achieved by modifying the top gate electrode with appropriate porous membranes or recognition elements. However, a change to the electrical properties of the gate electrode can significantly degrade transistor characteristics. To better understand this behaviour, we have explored the effect of gate conductance on HIFET performance, using PEDOT:PSS films of varied thickness as a model gate electrode. As gate conductance increases, key figures of merit including ON/OFF ratio, threshold voltage and transconductance improve until approaching a plateau. We understand this effect in terms of a change in the magnitude of the effective gate voltage. These results imply widely applicable design rules, where good transistor functionality can be achieved with a range of gate conductance values that lie in the plateau region, allowing flexibility to incorporate poorly conducting materials that facilitate sensitivity.

1:50 – 2:00pm Open discussion


During the seminar:

  • Please keep your microphone muted unless you are speaking. This is to reduce the background noise and avoid disrupting the presenter.
  • You will be automatically muted when you join the virtual meeting room. To speak, you will need to unmute yourself by using the audio controls in the lower left of the Zoom window.
  • If you have not used Zoom before, then it is recommended that you join 5 minutes before the starting time to ensure that you have your software set up correctly.

Please be aware that the talks will be recorded and posted on the AUCAOS website.

Previous seminars

Previous seminars can be viewed here:

Call for abstracts

Seminars are held on the first Wednesday of each month.

In the spirit of building a community in these challenging times, you are encouraged to give a talk. Do you have a talk that you would have given at a conference that was cancelled? Please consider adapting that talk for this format.

Submit abstract by email to bronson[dot]philippa[at]jcu[dot]edu[dot]au.