Modeling Semiconducting polymers: Computational Investigation of Rotational Barriers and Electrical Structures of Donor-Acceptor Polymers

• Grant number: 24/21911-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: March 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Florian Steffen Günther
• Grantee: Joabe Calçavara Marins de Miranda
• Host Institution: Instituto de Geociências e Ciências Exatas (IGCE). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil

Abstract

Semiconducting polymers hold promise for a variety of electronic applications due to their flexibility and tunable properties, making them suitable for devices like solar cells and transistors, but more importantly for new types of devices such as organic electrochemical sensors or thermoelectric devices. To optimize these materials, it is essential to understand their geometrical properties at the molecular level, which can be analyzed using quantum mechanics-based methods. The here proposed project aims at evaluating the structural properties of donor-acceptor polymers composed of naphthalene diimide (NDI), thiophene, thiazole, and diketopyrrolopyrrole (DPP) by means of Density Functional based Tight Binding (DFTB), a simplified and computationally efficient approach within Density Functional Theory (DFT). The study's primary objectives are to analyze rotational energy barriers and frontier orbitals and how they are influenced by functionalization through polar sidechains. The specific tasks include generating and optimizing molecular structures for oligomeric and polymeric forms, evaluating rotational barriers, and assessing the effects of polarized side chains. These insights are crucial for understanding the factors that control electronic behavior in functionalized semiconducting polymers. In addition to its research goals, the project aims to introduce the student to computational quantum chemistry by training the use of modeling software, input file setup, and data interpretation. Moreover, the work will provide an introduction into the multidisciplinary research field of organic electronics and build essential skills for future scientific works within a post-graduation program.