PhD Studentship: High-Resolution Imaging of Conjugated Polymers for Greener Synthesis

A fully funded 3.5 years PhD position in the field of molecular imaging of conjugated polymers is available in the group of Prof. Giovanni Costantini at the University of Birmingham.

Conjugated polymers are a class of organic materials that are attracting increasing attention as alternatives to inorganic semiconductors for their tuneable chemical structures, low-cost production, light weight, extreme mechanical flexibility and biocompatibility. They are becoming the material of choice for a number of advanced applications ranging from organic photovoltaics and thermoelectrics, to (bio)medical devices, to neuromorphic computing. However, the most established polymerisation approaches involve expensive and complex reaction procedures that typically require the use of polluting transition metal catalysts and generate hazardous byproducts. Alternative greener and more environmentally-sustainable synthetic pathways are thus actively sought after, with direct arylation polymerisation (DArP) being one of the most promising ones, thanks to its simpler and less toxic chemistry. Unfortunately, conjugated polymers made by DArP often show an increased density of structural defects resulting in lower polymerisation yields and a worse performance in devices. Exactly understanding the nature and frequencies of these defects is, therefore, key to the ability of fine-tuning the DArP synthesis and producing improved polymers. However, since these defects are extremely hard to identify and characterise by means of traditional analytical methodologies, current progress in the field is very much based on inefficient trial and error approaches.

The Costantini Group has recently demonstrated that by combining electrospray deposition (ESD) with scanning tunnelling microscopy (STM) it is possible to deposit intact conjugated polymers in ultrahigh vacuum (UHV) and to acquire sub-molecular resolved images, revealing their composition and structure at a level that is impossible with any other present analytical technique (e.g. Sci. Adv., 2018, 4, eaas9543 ; Adv. Mater., 2020, 32, 2000063 ; J. Am. Chem. Soc., 2021, 143, 11007 ). This breakthrough resulted in a transformative new approach for the characterisation of conjugated polymers based on an unprecedented molecular-scale insight into the microstructural characteristics of these functional macromolecules. This includes the precise sequencing of their backbones, the identification of structural defects and the possible correlations of these defects, the polymer assembly patterns and the acquisition of complete mass distributions. The successful candidate will have access to a worldwide unique ESD-STM equipment to investigate the exact sequence and conformation of a range of DArP-produced conjugated polymers, with the goal of delivering a molecular-scale benchmark for the design principles employed in their synthesis. Through collaborations with world leading synthetic groups at the University of Oxford (UK), University of Cambridge (UK), Chemnitz University of Technology (Germany) and Georgia Tech (USA), this unique insight into the compositional and structural properties of DArP polymers will be fed back into the synthetic pathways in order to fabricate highly performing materials via greener chemistry.

Funding for this position is open to UK applicants and the 3.5 years studentship will commence in October 2023.

Previous hands-on experience in scanning probe microscopy and/or surface science is advantageous but not necessary. Enquiries and informal applications should include a C.V. and be addressed as soon as possible to Prof. Giovanni Costantini ([email protected] ).

References:

Sci. Adv., 2018, 4, eaas9543 Adv. Mater., 2020, 32, 2000063 J. Am. Chem. Soc., 2021, 143, 11007

Funding

This is a fully funded (stipend+fees) 3.5 years PhD position and is open to UK applicants.