PhD Position in Molecular Chemistry (M/F): π-Conjugated Systems for Organic Electronics: Synthesis, Properties, and Integration into Simplified OLEDs

Job Description

Thesis Subject

Organic electronics (OE) starts to play a major role in electronics and will undoubtedly become a key player of future technologies. This emerging field is based on the use of organic semiconductors. The Phosphorescent Organic Light Emitting Diode (PhOLED) is currently the flagship device of this technology. A PhOLED is a device in which a light-emitting layer is sandwiched between several other organic material layers, all deposited between two electrodes. Upon application of an electric field, the PhOLED emits light via electroluminescence. In a PhOLED, the emitting layer consists of a host–guest system composed of an organic host matrix and a phosphorescent emitter (organometallic complex). The operating principle relies on the generation and recombination of electron–hole pairs (excitons) within the organic matrix, followed by energy transfer to the phosphorescent emitter. Over the past decade, significant research efforts have focused on improving host materials to better match the electronic properties of phosphorescent emitters. Through molecular engineering of these hosts, PhOLEDs performance have been significantly increase, with external quantum efficiencies now exceeding 35%. Our group, based at the Institut des Sciences Chimiques de Rennes (ISCR), is internationally recognized in the field of host materials and has reported several world-record PhOLED performances in recent years.
However, OLED technology still faces several major challenges. One of the most critical issues is related to the complexity of the multilayer architecture. Indeed, highly efficient OLEDs require the stacking of multiple organic layers to maximize charge recombination. Therefore, simplifying device architecture is a key direction toward more sustainable electronics. Single-layer PhOLEDs (SL-PhOLEDs), consisting only of electrodes and a single emissive layer (host + phosphorescent emitter), represent this new generation of simplified devices. The aim of this PhD project is to take a significant step forward in the field by synthesizing new generations of π-conjugated organic host materials for applications in white-emitting SL-PhOLEDs, which are currently absent from the literature. This project will focus on developing, through innovative molecular design strategies, bipolar host materials with high triplet energy levels (above 2.8 eV). Various pi-conjugated structures will be explored, including those based on bio-sourced materials. The project is built on strong foundations, as the host team currently holds the performance record for this technology, with a green SL-PhOLED exhibiting the highest efficiency reported to date (22%).
This project is at the forefront of international research and will be carried out in collaboration with Soochow University (Prof. Z. Jiang, China) and the Institut d'Electronique et des Technologies du Numérique (IETR, Dr. E. Jacques, Dr. F. Lucas, Rennes) for device fabrication and characterization. The group of Prof Jérôme Cornil at the University of Mons (Belgium) will also be involved. This project is intended for a highly motivated and dynamic student with a strong background in synthetic organic chemistry. Knowledge and/or initial experience in (i) electrochemical and/or photophysical analysis or (ii) molecular modeling would be an asset but is not required. The PhD candidate will join the Condensed Matter and Electroactive Systems team, specifically the group led by Cyril Poriel. The PhD will be supervised by Cyril Poriel (CNRS Research Director) and Cassandre Quinton (CNRS Researcher). Interested candidates are encouraged to contact C. Poriel or C. Quinton for further information about the project.

Your Work Environment

The project will be carried out at ISCR within the Condensed Matter and Electroactive Systems team (Rennes). The PhD will be supervised by Cyril Poriel (CNRS Research Director) and Cassandre Quinton (CNRS Researcher).

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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