Self-assembled Active Multichromophoric Monolayers to Tune Interfacial Optoelectronic Properties

**SELF-ASSEMBLED ACTIVE MULTICHROMOPHORIC MONOLAYERS TO TUNE INTERFACIAL OPTOELECTRONIC PROPERTIES**:

- Réf **ABG-128719**
- Sujet de Thèse
- 18/02/2025
- Contrat doctoral
- Institut Matériaux Microélectronique Nanoscience de Provence (IM2NP)
- Lieu de travail- Toulon / Marseille - Provence-Alpes-Côte d'Azur - France
- Intitulé du sujet- SELF-ASSEMBLED ACTIVE MULTICHROMOPHORIC MONOLAYERS TO TUNE INTERFACIAL OPTOELECTRONIC PROPERTIES
- Champs scientifiques- Physique
- Chimie
- Mots clés- Self-assembled molecular monolayers, push-pull chromophores, photovoltaics

**Description du sujet**:

- During the last years, chemists have paid deep attention to “push-pull” organic compounds bearing electron donor (D) and acceptor (A) groups linked by π-conjugated bridges [5] owing to their dipole induced by a charge transfer from D to A, and their appealing non linear optical response. The non linear optical properties of such D-π-A compounds can be finely tuned by selecting appropriate D & A units, and π-bridges at suitable positions. However, very few studies have focused on their adsorption on the surface [6], perhaps due to their uncontrolled orientation.
- Self-assembled monolayers will be obtained by transfer of the molecules from a solution to the surface. First, the deposition parameters (solvent nature, concentration, temperature, duration, ) will be optimized. The quality of the layers produced will then be evaluated by various surface analysis techniques available in the laboratory or at partner’s (ellipsometry, contact angles, quartz crystal microbalance, UV-visible, infrared, XPS, UPS, IPES,spectroscopies), and in particular at the local level by atomic force and electric force microscopy (AFM, EFM) and scanning tunneling microscopy (STM). Then, the electric properties will be studied via capacitance-voltage (C-V) and current-voltage (I-V) analyzes locally by STM/EFM microscopy, and more generally by means of InGa droplet at the eutectic.
- The following goals should be reached:

- Synthesis of a new bi
- or multichromophoric molecule series with various donor and acceptor groups allowing to modulate the dipole moment (achieved by CINaM in Marseille).
- _Ab initio_ calculations to identify the level position of HOMO (highest occupied molecular orbital) & LUMO (lowest unoccupied molecular orbital) of multichromophores (collab. with LPS at Orsay)
- Optimization of the deposition parameters such as temperature, solvent, concentration, to make a dense, compact, and well controlled SAM with oriented dipoles.
- Highlighting the electrical properties versus the structure of the interface. Particularly, we will focus on novel SAMs as ultra-thin weakly resistive interfacial electron & hole transport layers (ETL & HTL) based on new π-conjugated bichromophoric compounds tethered on a unique anchoring unit for organic solar cells. These bichromophoric structures will have added values compared to the simple ones in terms of dipole, charge transport, photoinduced charge transfer, charge recombination hindrance. Their implementation in model organic solar cells (regular-based devices) will be done in order to demonstrate their efficiencies. In addition, studies on the stability and degradation mechanisms of the novel SAMs under operation and damp/heat/light conditions will be performed in order to identify and get deeper insights about structure-property relationships.
- Funding: Doctoral contract from the ministry (MESRI)
- Keywords: Self-assembled molecular monolayers, push-pull bichromophores, dipole
- References:

- 1. A. Ulman,_ An Introduction to Ultrathin Organic Films, Academic Press Ed., Boston_ (1991); R.K. Vijayaraghavan _et al._, _J. Phys. _Chem. C_ 117 (2013) 16820
- 2. J.J. Cartus and al, _ACS Omega_ 6 (2021) 32270-32276
- 3. A. Asyuda _et al_., _J. Phys. _Chem. C_ 124 (2020), 8775-8785
- 4. A. Aster _et al_, _Chem. Sci._ 10 (2019) 10629; J.L. Weber et al. _Chem. Sci_. (2021) doi : 10.1039/d0sc03381b
- 5. V.Malytskyi, J.J.Simon, L.Patrone, J.M.Raimundo,_ RSC Adv. _5 (2015) 354
- 6. V.Malytskyi, J.J.Simon, L.Patrone, J.M.Raimundo,_ RSC Adv. _5 (2015) 26308_, _and_ _Tetrahedron _73 (2017) 57381

**Prise de fonction**:

- 01/09/2025

**Nature du financement**:

- Contrat doctoral

**Précisions sur le financement**:
**Présentation établissement et labo d'accueil**:

- Institut Matériaux Microélectronique Nanoscience de Provence (IM2NP)
- PHANO - Physique à l’échelle nanométrique
- EMONA - Nanostructures fonctionnelles & nano-composants
- MATER - Structure & chimie des matériaux
- DETECT - Détection, rayonnements et fiabilité
- ACSE - Analyse & conception des systèmes électroniques

Les équipes et département de l’IM2NP possèdent une expertise indéniable dans de nombreux domaines expérimentaux et théoriques couvrant la physique du solide, la chimie des matériaux, les dispositifs, circuits et systèmes intégrés, les circuits, la fiabilité, le traitement du signal et l’instrumentation. Cela concerne plus spécifiqu