Implementação de experimentos de espectroscopia ultrarrápida em polímeros conjugados

• Grant number: 11/18601-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2011
• End date: November 30, 2012
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Paulo Barbeitas Miranda
• Grantee: Caio Vaz Rimoli
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 07/08688-0 - Electronic and optoelectronic polymer devices, AP.TEM

Abstract

Data acquisition for ultrafast optical processes requires sophisticated instrumentation, capable of acquiring data in the timescales ranging from tens of fs to a few ns. This can be accomplished by ultrafast spectroscopy experiments - for example, measuring the charge and energy (excitons) transfer rate in thin polymer films. This project consists of finalizing the setup and characterizing the performance of an automated ultrafast pump-probe spectroscopy experimental station and also testing two methods for data acquisition. The main difference between them is the way the differential transmittance is obtained and calculated. The student should establish the sensitivity limits of each method and its main causes. The first measurements should be performed with a well-characterized polymer, poly (paraphenylene vinylene) - PPV, in order to verify the performance of the setup. Afterward, the student should learn how to prepare layer-by-layer PPV films, to produce polymeric heterostructures with a gradient in energy gap along the direction perpendicular to the substrate. Ultrafast spectroscopy will then be used to investigate the dynamics of intermolecular energy transfer in heterostructures with various bandgap architectures.(AU)