PHYSICAL CHEMISTRY OF NEW MATERIALS
The course aims to provide to the student an in-depth knowledge of the physical properties of conjugated organic and hybrid/organic systems, that constitute a class of materials with increasing technological interest for their use in photonics, optoelectronics and molecular electronics.
AIMS AND LEARNING OUTCOMES
This teaching, in relation to the acquisition of knowledge in the chemical and physical field, aims to provide the tools for the student to acquire a thorough understanding of the chemical and physical properties of conjugated organic materials and hybrid/organic systems. Since the latter are a class of materials from the growing applicative/technological interest for their use in the field of photonics, optoelectronics and molecular electronics.
In addition, the aim of the course is to develop the skills and competences of the student, enabling him to elaborate in a multidisciplinary approach the basic concepts previously acquired in the chemical and physical field.
Recall for chemical bonds and intermolecular forces.
- Ionic bond: Madelung constant, Ewald sum.
- Covalent bond: description according to MO and VB model, variational theorem, examples.
- Metallic bond.
- Intermolecular forces: Keesom, Debye and London. Development of a simple model for describing dispersive interaction forces.
Theoretical treatment of conjugated systems.
- Effective Hamiltonians: meaning and origin, application of the Huckel model for describing conjugate systems, advantages and limitations.
- Jahn-Teller effect, Symmetry and Electron-phonon interaction (hints).
- Proof of Fermi-Dirac distribution.
- Proof of the theorem of blocks and recalls of concepts typical of solid state physical chemistry (density of states, reciprocal pattern and Brillouin zones).
- Comparison between the "bottom up" and "top down" approach in describing a one-dimensional system (reference to a conjugate 1D system).
- Electronic properties of an infinite polyene / annulene: transition from semiconductor metal. Peierls distortion. SSH model. 2D conjugate system: graphite.
Organic vs inorganic semiconductors.
- General properties, conductivity, effective mass, charge load mobility.
- Deriving the law of mass action.
- Dropping, comparison between the case of organic and inorganic semiconductor.
- Solitones, polarones, bipolar and excitons.
- Charge transport in Organic Semiconductors (hints): Developnet of a simple model to identify the main factors that characterize the transport process (metal / organic interface). Importance of bulk organization and intermolecular interactions.
- Potential contact between organic / metal and organic / semi-conductor interfaces.
- Devices: OLED and Solar Cells. Operation, theoretical criteria for choosing the conjugated system to be used in the device. Examples of modeling.
Depending on the time available in the development of the course, the following topics may also be included:
- Introduction: Jablonski Diagram
- Schroedinger time-dependent equation (hints).
- Equation of liouville and master equation.
- Deriving from Fermi's golden rule: examples.
- Time correlation function: examples.
- Electron-phonon interaction.
Energy or electron transfer processes
- Marcus's theory.
- Foerster and Dexter theory.
Notes (in Italian) will be provided.
For the general part related to the properties of the solid state
- C. Kittel Introduction to solid state physics
Ricevimento: All days, by appointment.
MASSIMO OTTONELLI (President)
It is evaluated the student's ability to apply the methods studied, in the description of the material properties, by discussing specific cases combined with an audit of the depth and coherency of the knowledge and methodology described in the course.
The oral examination is conducted by two faculty members and has a duration of at least 30 minutes.