Organic semiconductors find their main application in OLEDs – organic light-emitting diodes – that are becoming the dominant technology for mobile displays, as they are bright, color-pure, and allow curved "infinity" displays that bend around the edge. In today's displays, it is possible to reach a resolution of about 500ppi (pixels per inch). This is not sufficient for the future. In mobile displays, there is a trend to integrate multiple invisible sensors, such as photodetector pixels for fingerprinting, into the display body. These will require area on the display, and as a consequence the OLED pixels should shrink. Also, augmented reality displays will demand a pixel density exceeding 1500ppi to match the retina resolution of the human eye. Therefore, new processes are being explored for scaling down OLED pixel size. For example, some groups work on printed OLEDs, others pattern OLEDs by photolithography and etch. However, these processes have an impact on OLED lifetime. Therefore, fundamentals of OLED degradation mechanisms related to fine pixel patterning need to be understood.
The purpose of this PhD is to research fundamental processes of degradation of organic semiconductors as a result of lithographic patterning of devices such OLEDs, organic photodetectors (OPDs), and quantum-dot photodetectors (QDPDs). Device dimensions of 2 to 5 microns are considered. The killer impurities that are introduced by the patterning process will be identified, and strategies will be invented to avoid them. The systematic investigation will consist of fabricating reference devices, exposing them to a series of controlled environments of chemicals, and perform analysis to map relationships and bring understanding of the phenomena. Specifically, chemical as well as opto-electronic analysis is foreseen, supported by modelling.
You are a highly motivated recent graduate holding a master's degree in chemistry, material science, nano-engineering, or related. You have an interest in organic semiconductor devices, and like a multi-disciplinary subject in which you will relate understanding of processes and chemicals to optical and electrical degradation at device level. You will be expected to work safely in a cleanroom environment and acquire processing and lab skills. You will regularly present your results. You are a team player and have good communication skills as you will work in a multidisciplinary and multicultural team spanning several imec departments. Given the international character of imec, an excellent knowledge of English is a must.
Required background: master’s degree in chemistry, material science, nano-engineering, or (device) physics; interest and/or background in organic semiconductors is a strong plus
Type of work: 10% literature study, 50% processing, 40% characterization
Supervisor: Paul Heremans
Daily advisor: Tung Huei Ke
The reference code for this position is 2020-110. Mention this reference code on your application form.
Chinese nationals who wish to apply for the CSC scholarship, should use the following code when applying for this topic: CSC2020-59.