Studying organic transistors by charge modulation spectroscopy (CMS)

• Grant number: 15/21872-1
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: January 12, 2016
• End date: December 31, 2016
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Paulo Barbeitas Miranda
• Grantee: Douglas José Correia Gomes
• Supervisor: Guglielmo Lanzani
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Institution abroad: Politecnico di Milano, Italy
• Associated to the scholarship: 13/07328-1 - Investigation of interfaces in polymeric light-emitting diodes (PLEDs) by SFG spectroscopy, BP.DR

Abstract

Electronic devices based on organic semiconducting materials, such as transistors, have attracted much research interest due to their potential for unique applications in the vast field of large area and flexible electronics, including wearable electronics, personal bio-medical devices and distributed sensors. The operation of organic eld-eect transistors (OFETs) depends on the modulation of charge accumulation at the interface between an organic semiconductor and a dielectric material, induced by the voltage applied at the gate electrode. In this proposal we aim at mapping the charge accumulation in the channel of OFETs using charge modulation microscopy (CMM), which offers a non-invasive method to investigate the nanometer thick charge accumulation layer in an actual working device. The use of a polarized probe will also allow investigating the relationship between microstructure and charge transport properties in OFETs. These processes will be investigated in state-of-the-art devices produced at the Italian host institution (POLIMI), using their setup for charge modulation microscopy (CMM). During the one-year stay of the candidate PhD student in Italy, he will be trained in CMM of organic materials, and use it to investigate charge accumulation and transport in organic transistors. These results will be compared with images of the electric field distribution in OFETs obtained at IFSC-USP, using sum-frequency generation (SFG) microscopy. Together, they should yield a better understanding of the charge accumulation and transport processes in OFETs, and possibly suggest ways to improve their fabrication and performance. (AU)