Prussian Blue Analogs (PBAs) have been extensively explored in the past two decades because of their remarkable magnetic, optical and electrical properties.

Recently, we developed original photo- and electro-switchable A{Fe4Co4} cubic complexes containing an inserted alkali ion (A). The cubes are composed of three [Fe(II),LS-CN-Co(III),LS] pairs (and only one [Fe(II),LS-CN-Co(II),HS]) which can show photo-induced Electron Transfer coupled to a Spin Transition (ETCST). In addition to their photomagnetic properties, these cubes are ideal candidates for the fabrication of molecular electronic devices because of the multiple electron transfers they offer. Indeed, the cobalt spin change could be exploited for the fabrication of organic field-effect transistors.

In order to develop this aspect, the system needs to be immobilized onto a surface. This strategy requires RTp ligands to be tailored with anchoring groups. The strong versatility of the scorpionate ligands has been recently used by the ERMMES team to develop new materials. This know-how will be used to design Fe-Co cubes functionalized with anchoring functions like thiophene derivatives, thiols or diazonium salts.

In a second stage, this cube will be studied by using ultra-fast electrochemical methods, and the standard potentials as well as the kinetics of spin transitions will be determined.

1- Sujet de thèse proposé par Alain Pailleret

 

     Comportement photo-électrochimique et opto-électronique    

    des nitrures de carbone amorphes (a-CNx) riches en azote   

 

Informations générales: 

Laboratoire d’accueil:

LISE UMR CNRS/SU 8235,

équipe MATTERFEEL : https://www.lise.upmc.fr/theme2

Paris, France

Date de démarrage : Octobre 2019

Durée : 36 mois

Temps de travail : Temps plein

Rémunération nette : 1422 € net / mois

Directeur de thèse : Alain PAILLERET, MCF-HDR à Sorbonne Université

E-mail: alain.pailleret@sorbonne-universite.fr

 

Contexte et objectifs :

Ce projet de thèse vise à définir le comportement photo-électrochimique et opto-électronique de couches minces de nitrures de carbone amorphes riches en azote produites au LISE par pulvérisation réactive, et éventuellement traitées thermiquement. Pour cela, des techniques classiques (carac. I-V et I-t à l’obscurité ou sous éclairement, Mott-Schottky…) ou plus ambitieuses telles que l’AFM photoconducteur, l’IPCE (rendement quantique), ou encore la spectroscopie de photocourant modulée en intensité (IMPS) qui permet d’évaluer les phénomènes de perte par recombinaison de charge, seront exploitées. Les comportements ainsi définis seront ensuite corrélés avec la composition chimique (rapport C/N, autres éléments-traces (Ar, O, H) et l’hybridation des couches qui elles seront déterminées par XPS, FTIR ou des techniques nucléaires telles que l’ERDA, la NRA ou la RBS. En fonction de la vitesse de progression de l’étude et des résultats, des applications dans les domaines de la photo-électrocatalyse, voir du photovoltaïque (jonctions a-CNx/polymère conducteur électronique par exemple), seront abordées.

Profil recherché :

Le candidat devra être titulaire d’un diplôme de Master en chimie ou en physique, voire en ingénierie chimique, obtenu avec mention. Il devra également démontrer un intérêt profond et des compétences évidentes pour la caractérisation chimique, opto-électronique et électrochimique des semi-conducteurs en couches minces et des dispositifs élémentaires qui les intègrent.

Le candidat saura faire preuve de rigueur dans la réalisation, la présentation et l’interprétation d’expériences. Il sera capable de mener à bien un suivi bibliographique sur toute la durée de sa thèse et de rédiger une étude scientifique conséquente tant en français qu’en anglais.

 

Procédure de dépôt de candidature

Les candidat(e)s intéressé(e)s sont invité(e)s à transmettre le plus rapidement possible leur dossier de candidature (lettre de motivation, CV, relevés de notes de Master (1^ère et 2^ème année), et référents) par courrier électronique à Alain Pailleret (alain.pailleret@sorbonne-universite.fr).

     Development of green composite materials centered on    

    (carbonized)polydopamine for energy storage and conversion    

 

General information: 

Host Laboratory: LISE UMR8235 SU, CNRS (MATTERFEEL team), Paris, France

Starting date: October or November 2019

Length: 36 months

Working time: Full time

Thesis supervisor: Catherine Debiemme-Chouvy, DR CNRS

E-mail: catherine.debiemme-chouvy@sorbonne-universite.fr

Co-supervisor: Ozlem Sel, CR CNRS

E-mail: ozlem.sel@sorbonne-universite.fr

Ecole doctorale : Chimie Physique et Chimie Analytique de Paris Centre (ED 388)

 

Context and topic:

Tremendous efforts have been devoted into the design of novel materials for energy, particularly with the association of various functional nanomaterials such as carbon or conducting polymers with metallic nanoparticles (NP) or metal oxides (MO), offering synergic properties. Among the carbon based materials which have been playing a significant role in the development of alternative clean and sustainable energy technologies, graphene or reduced graphene oxide (rGO) has spurred significant interest in energy storage due to its high specific surface area, superior electronic conductivity and chemical resilience.

An emerging polymer in the energy storage or conversion domain is a mimic of the specialized adhesive foot protein secreted from mussels. It is based on dopamine which has a catechol structure and one amine group, and can be (electro)polymerized forming adhesive polydopamine (PDA) coating on various substrates. It can be combined with non-metallic elements and metals nanoparticles; enabling nanomaterials with various components that can be optimized for multi-functional purposes. One remarkable property is obtained by carbonization of PDA (cPDA) which transforms it to a highly conductive N-doped graphene like carbon. Due to these outstanding features, i.e. unmatched adhesive properties, flexible componential tunability, and structural regulation, (c)PDA-derived composite materials are deservedly getting popular in energy domain.

This PhD project aims at exploiting PDA’s suitability for composite material synthesis by developing new materials derived from PDA or cPDA to be able to fabricate materials with tunable functions for a target application (energy storage or conversion). The project will benefit from advanced coupled electrochemical methods developed at LISE lab to shed light on the structure-function and performance relation of the composites for applications such as supercapacitors or fuel cells. Specifically, three main objectives will be pursued during this research project: (i) the synthesis of new composite materials (rGO@(c)PDA, rGO@(c)PDA/MO, rGO@(c)PDA/NP), followed by (ii) the determination of their electrochemical properties and finally (iii) test in device configuration: in Swagelok type cells for their evaluation as supercapacitor electrodes or in the fuel cell configuration for the composites optimized for alcohol electrooxidation reaction.

 

Tasks and Principle Activities:

Task I: (c)PDA-based composite electrode synthesis / Characterizations / Performance evaluation

Task II: Classical electrochemical and in situ coupled advanced analysis (EQCM, electrogravimetric and electroacoustic impedance, DEMS)

Task III: Analysis / Modelling of the advanced electrochemical analysis and cycling performance data

Task IV: Data presentation, manuscript preparation, Ph.D. thesis writing.

 

Profile of the candidate:

The candidate must have a Master’s Degree or an engineering degree in:

• Materials science or physical chemistry obtained with excellent grades.

• Knowledge in electrochemistry and in energy materials’ characterization is required.

• A good command of English (written and oral) is necessary.

 

Application procedure:

Please send your cover letter, CV, masters’ degree grades (transcripts) and the contact information for at least one reference to:

catherine.debiemme-chouvy@sorbonne-universite.fr and ozlem.sel@sorbonne-universite.fr