|SCIENTIFIC DISCIPLINARY SECTOR||CHIM/04|
Organic and polymer semiconductors are revolutioning the consummer electronic market. Nowdays, mobile telephones and TV-sets are often equipped with OLED screens while wearable electronics is more and more important. However, the knowledge of materials allowing for this revolution is poor. Aim of this class is to provide a knowledge of chemistry and physics fundamentals, the understanding of material properties and working principles of electronic devices made by organic semiconductors.
Basic knowledge of chemical and physical properties of conjugated polymers and organic semiconductors. Use of such materials in organic optoelectronics and photonic devices (sensors, transistor, led and photovoltaic cells)
At the end of the class, students are expected to understand:
Main differences between the electronic structure of organic and inorganic semiconductors. Main qualitative differences of the electronic structure of isolated and interacting chains. The concept of energy gap, bandwidth, carrier mobility and intermolecular interactions. The meaning of conjugation length. The qualitative role of disorder in polymer semiconductors on the carrier mobility.
The importance of solubility in pocessing. The qualitative effect of side chains on processability, controlling intermolecular interactions and solubility.
Methods to make conjugated polymers oriented and the qualitative effect on the optical properties
Main synthetic strategies to prepare conjugated polymers. The role of regioregularity. Tuning of the ionization potential, electron affinity and energy gap.
Fundamentals of spectroscopy and photophysics in organic semiconductors. The vibronic structure.
Working principlies of sensors, transistor, led and photovoltaic cells. Material strategies to improve their performances.
They have to be able to extract simple information on physical and chemical properties from absorption/fluorescence spectra of a conjugated polymer/molecule as described during the class with several examples.
Good knowledge of chemistry and physics of materials.
Lectures delivered by Power Point presentations available to students on AulaWeb. Simple classroom experiments on light matter interaction.
In case of emergency and only according to specific indications by the University of Genoa, the assessment method for the exam might be changed, including the possibility of an online procedure.
Section 1: electronic states & spectroscopy
Extended p-electron systems both in molecules and polymers. Conjugation length: ionization potential, electron affinity and HOMO-LUMO gap in the series ranging from ethylene to polyene. Electronic states for the polyene: introduction to the Hückel method for the isolated chain and for interacting macromolecules. Dimerization and Peierls distorsion: metal and semiconducting polymers. Conducting conjugated polymers: doping and applications. Charge transport in semiconducting and conducting polymers. Spectroscopy of conjugated systems: electronic transitions, Franck-Condon principle and vibronic transitions, fluorescence and lifetime, singlet and triplet excitons, Jablonski diagram and photophysics.
Section 2: Synthesis & material processing
Synthesis of main conjugated polymer families (polyacetylene, polythiophene, poly(p-phenylenevinylene)). Functionalization of chemical and physical properties of conjugated materials (solubility, ionization potential, electron affinity). Supramolecolar structure of conjugated polymers and role of aggregation in the solid state. Orientation techniques of conjugated polymers, optical and electronic properties anisotropy.
Section 3: Optoelectronic Devices
Working principles of devices made of conjugated molecules and polymers: sensors, devices for non-linear optics, OLED, PLED, OFET, photovoltaic cells and light harvesting based devices, wearable electronics. Role of the supramolecular structure on the main electronic properties of materials and of devices.
For studentes in Industrial Chemistry, a shorter program holds (4 cfu instead of 6 cfu). In particular, they are allowed to skip the details of electronic structure calculations and light-matter interaction
References & Books
DAVIDE COMORETTO (President)
FRANCESCO BUATIER DE MONGEOT (President Substitute)
MARINA ALLOISIO (Substitute)
MAURIZIO CANEPA (Substitute)
Tentative start will be September 13th.
SINCE IT IS IMPOSSIBLE TO PROVIDE A DEFINITIVE LESSON SCHEDULE NOW DUE TO THE COVID EMERGENCY AND PROVISIONS RELEASED BY UNIGE CONCERNING THE TEACHING ACTIVITY, WE STRONGLY RECCOMMEND STUDENTS TO FREQUENTLY VISIT THE FOLLOWING WEBSITES FOR AN UPDATE https://corsi.unige.it/9020/p/studenti-orario; https://chimica.unige.it/node/390
•Oral exam held by two professors, one of them being D. Comoretto.
•The duration of the exam is no shorter than 30 minutes.
•The student discusses an original power-point presentation or written relation on an item related to the course.
•The student selects the item more suitable to his/her aptitudes/needs with the help of the teacher among those reported in the scientific literature and/or provided on aula-web (usually one or two papers).
•The presentation have to be suitable for understanding by students of the same level.
•The student must show to have understood main physical/chemical/technological fundamentals related to the topics and to use the suitable technical vocabulary (up to 20/30).
•The clarity of presentation (up to 5/30) and ability to answer questions (up 5/30) will be also evaluated.
•Goal of the exam is to verify the achievement of the class aims.
•If aims are not achieved, the student is invited to make a deeper study and to ask the teacher for additional explanations before repeating the exam.
•In order to guarantee the correspondence between aims and exam topics, the detailed program is uploaded to AulaWeb and described at the beginning of the course.